noise."Inferred Ethanol Content · 2:21am Jan 28th, 2021
This is short and not fully diagnosed, just as a fair warning. So I might not be entirely right in my diagnosis or repair (but I think I am at least close, for reasons we’ll get to).
First, though, I gotta have a picture to lure you all in.
Sometime last year, I was griping about getting less-than-helpful information at all from my manager. You know, like take the car for a drive, listen for a noise. What kind of noise? Who knows.
Thus it was that I found myself holding the keys for a 2013 F-150 with a 3.7L (I think) naturally-aspirated V6. It has an electrical problem.
Now, I’ve talked about networks and electricity and sad Fords that make too much electricity; this is as useful as going to your doctor and telling him you don’t feel good and then not offering any other specifics which might aid in diagnostics.
I could run a full-system scan on the truck, and I could try and control every single electrical device it’s got and see what happens or doesn’t. And, in fact, since the airbag warning light is on and my manager won’t give me any useful information, I might as well. See what pops up, maybe it’ll be the clue to the whole thing.
I get some codes, but they aren’t terribly informative. The deployment loop in the left front seatbelt pretensioner is open (that’s the airbag code), and that won’t really affect anything until the truck crashes. At that point, it might be the difference between walking it off or taking a very long dirt nap; that’s probably not the customer’s immediate concern.
A couple of the body and infotainment modules have codes ‘cause they can’t find the radio. Which is also reasonable; the truck has an aftermarket radio in it. SYNC (technically, the APIM and the FCIM-A) aren’t very happy about that. I talked about the radio and the screen in a Ford some time back.
Also, both the engine control module (ECM) and transmission control module (TCM) have set the same code for losing communication with the body control module (BCM); that’s a history code, which means I can probably ignore it for now.
Which leaves me with no useful information.
Manager came by and asked what I’d found. I said nothing that I didn’t expect.
“Explain.”
So I gave him a rundown of the codes, and the fact that it had an aftermarket radio.
He said he’d call the customer.
Also at some point, I found out that the truck had been at another shop in town because they couldn’t figure out the electrical problem. If they only had the information I had to work with, no wonder they couldn’t figure it out. [Some years back, I reprogrammed an Econoline for them, after the customer installed his own internet-ordered PCM and they installed an instrument panel cluster (in those days, Ford called the IPC the HEC).]
It turns out that the vast majority of the customer’s problems were caused by there being a non-Ford radio that wasn’t networked in the Ford. In many modern cars, the radio does a lot of things besides just play music and maybe show you a picture of what’s behind you when you back up, and all those things won’t work like they should when the radio’s gone.
The other problem was when it was cold, the engine would flood unless the customer held the gas pedal to the floor (putting it in ‘clear flood’ mode). It hadn’t done that for me, but then it hadn’t been cold, either.
That was information, and since I already knew that there wasn’t a code to explain it, and the lack of a radio wouldn’t explain it, I could leave the thing sit until it got cold and see what happened, or I could check Identifix and find out if there was some common failure I could check while it was warm. Maybe a sensor that got biased and only really affected it when the engine (and the outside) was cold, but if I knew to look at it in the scan data, I might find it.
And I got a hit straightaway with symptoms that sounded like what the customer described. A bad mass airflow sensor which caused the truck to think it had too much ethanol in the fuel, which—since ethanol is less energy-dense than gasoline—would mean it would want to have the injectors open for longer on cold start. If that ethanol wasn’t really there, it would flood itself out.
There were two things I could look for to find that out. The first is the ‘inferred ethanol content’ (we’ll get back to why it’s called that), and the second was the MAF readings. Ford, for years, has built the barometric pressure readings into the MAF (altitude also matters for fuel metering), and while what the readings should be at idle kinda vary, the local barometric pressure doesn’t vary that much no matter what engine you’re working on.
I didn’t know where to find the data for the ethanol content, but I did know where to find the baro data, and I was right, it was wrong. It was reading about 27inHg, and it should have been around 29.5. I now know that the mass airflow sensor is bad.
I also checked the inferred ethanol content, and found out that it was at 44%. That’s probably not right; winter blend in Michigan should be at most 10% . . . although, admittedly, I don’t know if the guy puts E85 in his truck. I could check that, but it’s easier to fix the problem I know it has.
Sidebar
In the interests of saving the environment/tax writeoffs/keeping corn prices high (your mileage may vary), many vehicles are ‘flex fuel,’ which means that they can run on up to a 85% ethanol (and gasoline) blend. In Michigan, gas normally has 10% ethanol added.
Because ethanol is less energy-dense than gasoline, fuel injectors need to open for longer to get more fuel through them if there’s more ethanol in the vehicle. And while the automakers could require you to only put E85 in the tank, most customers wouldn’t buy such a car, so instead they’re flexible. You can put none in, you can put a couple gallons in, you can fill the tank with it, doesn’t matter.
Obviously, they can’t rely on the customer to tell the car what just got put in its tank, so the car has to figure it out. There are two ways that I know of. The most obvious is a fuel composition sensor; you stick that in the fuel line and it watches the fuel flowing by, analyzes it, and determines how much alcohol is in there, then tells the PCM.
While that system is the most accurate, it requires an extra sensor, extra wires, and two extra connections in the fuel line (plus a bracket to mount it on, and a place to put it). GM usually does this.
The other option is to use the sensors you’ve already got. The mass airflow sensor knows how much air went into the engine, the injectors know how much fuel they put in the cylinder, and the oxygen sensors analyze how it burned. If programmed with some clever algorithms, the vehicle can determine from that how much ethanol is in the fuel.
In the early 2000s, Chrysler suggested that you never put less than half a tank of different fuel in your tank if you were switching [both of my older minivans are flex-fuel], and I would presume the ‘what’s in the tank’ algorithm got activated whenever it noticed that the fuel level had gone up. This Ford is programmed to think that the fuel/alcohol ratio can change while in motion, which we’ll get to later.
My manager was a skeptic of course, but the new MAF was ordered and installed. I reset keep-alive-memory, which on a Ford resets its learned engine management stuff to default. Interestingly, it also set the inferred ethanol content to 26%.
I took it on a test drive, doing wide-open-throttle passes to re-learn the baro sensor. It took a few before it figured it out, and I also noticed that the inferred ethanol content was all over the place. Better than before, but still ranging up and down which was kind of odd. Pick a number and stick with it, Ford.
I won’t bore you with me trying to explain to my manger that 30% (what it settled at after the test drive) is not half, it’s less than a third, and that E85 is so named because it’s 85% ethanol, and that E30 is also not half of E85. He also insisted that you had to go to ‘the big city’ to get ethanol fuel, apparently not aware that pretty much every Speedway in my neck of the woods has it, along with Meijer . . . but I digress.
I also asked if he knew how much ethanol they normally put in the fuel in Canada, since this was a re-imported Canadian truck (with the cold-weather package). He didn’t know, and I don’t either.
I did a little more digging and discovered that pretty much anything that changes the airflow into the engine might mess up the inferred value, and I also discovered that someone on Identifix had put in the wrong link in the Ford diagnosis without codes flowchart. I clicked on the test for ‘hard start, no codes,’ and it suggested I check to make sure the diesel fuel hadn’t gelled.
Since the kind of customer who might put in an aftermarket radio and black out the Ford emblems on his truck and put on a louder muffler would also be the kind of customer who might have a K&N air filter—which not only will change the airflow, but will also deposit oil onto the MAF and make it fail. Guess what had a K&N filter?
I put in a normal air filter, reset KAM, and noticed on startup the inferred ethanol content was now 24%. I took it for a shorter test drive—it was late in the day—and by the end of the drive, it hadn’t learned the alcohol content, but its range was now between 10% (likely) and 20% (probably not).
Before I forget to mention it, the inferred ethanol content reading was dynamic. Say it started out at 24%, and then I’d do a hard acceleration from the stop sign and it would drop to 13%, then slowly creep up to 18%, then drop down again when I gave it more load. Identifix mentioned in the tech tips that the computer assumes a lean exhaust means that there’s more ethanol in the fuel.
It’s also worth mention that fuel trims in general (how far, percentage-wise, the drift from the default in any given operating condition) can go +/-10% on a normally-functioning engine. It’s only when they get farther off that that you might have a problem.
Also, now that I’ve written the title, I realize that ‘inferred ethanol content’ could also be used to describe field sobriety tests. They don’t give you an actual number, but they give you a good idea, especially with multiple failures.
And I guess they’re kinda dynamic tests, too.
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Ah cars,you have so many things that can fail nowadays and they tend to be hard to reach.
5443164
I have a theory that the reason for this is ease/speed of manufacture.
5443181
What, attaching plastic pieces over the engine so that you can’t access parts of the engine.
5443149
Your problem sounds so very much like a joke I used to tell.
"How much can I drink? I have no idea. I'm a drunk, not a fucking accountant."
5443164
It’s honestly kind of a mixed bag in my experience. There’s stuff that a few decades ago would be horrible, and there’s stuff where I wonder why they did what they did. For example, everything on a 90s/2000s Venture is horrible; I’d rather pull off the intake to put in spark plugs than reach down into the neverland of GM’s bank 1.
True story, I didn’t know what the backside of that engine looked like until we replaced one, but I sure know what it felt like.
And don’t get me started on the valve cover gaskets on Chryslers with Mitsubishi engines of that era.
5443181
That is legit a factor, but there is some thought given to maintainability. Sometimes. If the engineer’s feeling generous.
5443184
That’s just to make it pretty.
And GM had a service bulletin to discard that plastic cover on 3.8L engines because (IIRC) it could cause a fire.
Also they’re great mouse habitats, which isn’t good for the customer, but keeps us in business fixing chewed wires.
5443187
This is true.
So, since we’re on topic, brief funny story from my former career driving tow truck. Got a call to an accident, and the dispatcher (who had a police radio in the office) mentioned that the cops weren’t sure if the driver was drunk or not.
To my mind, that seemed like a simple thing to figure out. Even if they can’t do the normal field tests due to injury, surely a breathalzyler would do the trick.
And then I got to the scene. Jeep Cherokee crashed into a pole, and it had been carrying I don’t know how many cases of wine in the back. During the accident, enough of them had broken that there was literally a lake of wine inside the thing, and every soft surface in the Jeep was saturated with wine . . . I have to imagine that the driver was, as well, and that if they got the brethalyzer anywhere near them, it’d just say ‘100%’. I probably ticked up a few points on the BAC scale just by breathing the fumes as I hooked the thing up.
I read a magazine article about ethanol problems. And one thing they said was that when they get it wrong (and I think they were specifically talking about a Ford) you sometimes have to trick it into resetting itself. And if it doesn't specifically have an ethanol reset in the stuff you can do on the scanner, that you have to make the car think you've put gas in the tank. So either put gas in the tank, or unwire the fuel level sensor and put the appropriate resistor across it to fool the PCM into thinking the tank is full. Then it'll like reevaluate the ethanol content.
Idk, honestly never had to deal with ethanol problems. There's plenty of E85 available, but it's rare that I ever find a customer who uses it. Except for one guy with a flex fuel Impala who'd apparently been using only E85 for several years, the entire time he'd owned the car, because he thought he had to. We were having stubborn misfires with that car, so I got him to put regular gas in it to see if it helped. For the record, I don't think it did. Oh wait, I can't remember what actually fixed it... so maybe it did.
5443242
Yeah, reset isn’t an option on the aftermarket (Snap-On) scanner, and it seems by the data to be dynamic, so a full reset (KAM, or disconnecting the battery and touching terminals together) is going to be of limited value. Putting gas in the tanks, maybe, but it looks dynamic on the scan tool, so that might be of limited use. Don’t honestly know.
None of our customers do AFAIK. I’ve considered it, but I don’t know how a clapped-out Caravan would deal with it (on the plus side, the MIL is already on, and it can’t be more on). I have seen a few GMs with defective fuel composition sensors and ‘fixed’ them by resetting it (I’ve never replaced one). Assuming the engineering and programming is on-point, shouldn’t make a drivability difference if it’s only E85 that goes in the tank or not, although I’ll admit that I don’t know what the long-term consequences are for the spark plugs nor if the engineers considered that. My cynical side says that, for example, GM built and (cheaply!) leased flex-fuel S10s in the late 90s and early 2000s without telling customers that their truck could theoretically run on Everclear; they just did it for the CAFE mileage because as far as the Fed was concerned, customers could put ethanol in it, right? (Now give me the CAFE credit for more Suburbans and Hummers)
5443256 Meh, there's no long term consequences to using ethanol. That's a load of baloney. Actually, E85 would probably keep your spark plugs sparkly clean lol
My old hag of a stepmother keeps saying I should get an IT job. I gave her a demonstration of why I'm just a hobbyist and unemployable.
I was panicking all day after dusting out her ancient mini-atx tower with all her passwords and years of financial and legal documents and there was no video output after plugging it back in again, failing to notice I plugged the monitor into the wrong HDMI port; The onboard one instead of the actual video card. I always miss the most basic things and suffer major anxiety and depression and lack of confidence for it.
Is ethanol fuel any good for 2-stroke mixes? Will some 2-stroke mix that needs to be used at the end of the season (diluted with regular flex fuel gas, of course) mess up the engine or spark plugs?
Thankfully, this turned out to be a lie (the short bit).
What is "‘clear flood’ mode", if you don't mind me asking?
"In Michigan, gas normally has 10% gasoline added."
Was that meant to be "10% ethanol"?
What's special about a K&N air filter here, also if you don't mind me asking?
And the fuel trims are for the amounts of fuel injected per injection? Or something else?
Thanks for the interesting information, as usual!
"#and it hasn't got any batponies in it either"
Well, now you've got one picture in the comments, at least. :)
5443229
"That’s just to make it pretty."
...I mean, if someone's looking under the hood in the first place, what are they expecting to see?
E85, running American cars on renewable solar power for over 20 years?
I wonder how far the fleet could drive if they switched to plant ethanol sources that were actually efficient?
Never mind cathedral diesels on coal slurry or transport vehicles on closed loop algae diesel?
Now for my little bit of relevant trivia from my limited knowledge base: Flex-Fuel vehicles are nothing new. The Ford Model T was designed to be flex-fuel. People had to adjust the timings manually beforehand, of course, since computers hadn't been invented yet, but they made that a relatively simple and easy process if one knew what they were doing. They could even run on up to 100% ethanol.
How is Pony Planet coming?
Fun side note on flex-fuel Caravans: If you only run them on E85 and the battery dies or is disconnected at some point, it'll consistently fail EPA smog check no matter how many or which drive cycles you do, until you tank up with normal gasoline and then run the drive cycles - apaprently there's some sort of tables in memory that the smog check computers will fail you for if they're not populated, and the ECU will only populate them when driven on normal gasoline, not E85.
Also, the techs at the emissions centers (and at the dealership) generally don't seem to know about this, for whatever reason. Maybe it just doesn't come up all that often, who knows?
Still seems funny that actually using the (supposedly) "environmentally friendly" feature would actually cause it to fail the emissions test. (Though I imagine that it'd've passed the old treadmill test easy on E85, even if it failed the OBD-II test that replaced it...)
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5443416
So could my mother's Hillman back in the 1970's. The car was older than that - it still had a hand crank. But just like the old model T, it could run on any mixture of alcohol.
Note - my Daihatsu Charade does not.
I dissolved the fuel pump internals by adding ethanol. It happened very quickly - I only drove a few kilometres before the engine stopped.
Why would a manufacturer build fuel system parts that dissolve on contact with ethanol?
My two cents on the whole ethanol thing.
I´m from Brasil and we had, a couple of decades ago, a program called "Proalcool". As the name infer, yes, it was aimed to make ethanol a viable fuel for the country. The first ethanol engines were made of 100% HELL...they failed a lot and it was near impossible to start the engine in cold (well...as cold as Brasil can get, wich is not much).
Couple of decades ahead and almost ALL vehicules here are now flex cars. Diesel is only used for trucks, buses and some suv´s. The good side is, ethanol is cheaper. And cleaner. And to be able to produce all the ethanol we consume AND export, we devasted a lot, and I mean A LOT of our forests.
Yeah, nice choice there....use diesel or gas and dies from lung cancer, or destroy the whole eco-system.
Also, our cars can run in ANY porcentage of gas and alcool. Hell, our gas have so much ethanol, it would probably blow any non-flex engine you use it. There is no need to have any special procedure, BUT, yes, there is always a but, if you use too much ethanol, the fuel has a tendency of "drying" any rubber in the engine with time. So any connections or plastic that comes in contact with ethanol for too long start to break apart. Sure, this does not happen overnight...but it IS advisable to use use gas every one in a while in order to keep those engine parts running without breaking apart. Other then that, it is all good.
5443268
In most modern engines, and the fuel not kept stored for a long time (although that’s a problem with gasoline, too).
The truck set a new code the day after I posted the blog; a data error in the PCM. It also kicked the ethanol percentage back up to 45% (ish) and then decided it had learned it. Friday, I reprogrammed the computer, took it for another drive, and it settled on around 25% ethanol content, which is still too high IMHO (I checked another FlexFuel car we had just for giggles, which was reading 0%), and we gave the truck back to the customer to drive and see what happens.
5443303
I just got a new computer today (this one is long in the tooth) and had to dig out an old VGA monitor ‘cause it turns out that this one won’t accept a monitor only in the HDMI hole. Now that I’ve set it up, it’s happy with that, but you try going through all the normal setup steps when you don’t have a monitor (as far as the computer knows). Can’t be done.
I also sometimes am referred to as the ‘tech expert’ at the shop because I know more about computers than most everyone else at the shop, but that’s honestly the level of expertise that someone on a Pee-Wee football team might have. I know the basic guidelines and how to make folders in Windows, and you plunk me in IT and I’m gonna flame out quick.
Given that in most places in the US ethanol is added to gasoline as a matter of course, the engine would be designed to accept that. Something really old or in a place where ethanol isn’t used, the engine would probably run, but there might be problems of incompatibility with rubber fuel lines, gaskets, etc. The big killer of a lot of small engines is that they sit with untreated fuel in them (I’m guilty of this) for the whole winter, and they gunk up. I doubt if the ethanol makes it any worse.
I do know a person who’s using leaded AVgas in small two-stroke engines and they seem to like it okay. Most of those engines are honestly simple enough it probably doesn’t matter exactly what you put in the tank, so long as its fresh.
5443318
Well, it was going to be and then I went on and on as I’m wont to do.
5443320
If an engine gets overfueled (flooded), you need a way to make it not add more, and in fuel-injected vehicles, that’s accomplished by holding the gas pedal to the floor as you crank, which makes the injectors not inject more.
That was the same way you’d do it on a carbureted engine, too, which is why they programmed it that way.
it was, yes. Correction made; thank you!
Most air filters are paper, and meant to be replaced when they’re dirty. K&N (and some other aftermarket filters) are cloth and can be washed and re-used; most of them also use a special oil to do something. Too much oil can contaminate the mass airflow sensor, and they also flow better than factory filters (in theory), which is fine except that the computer is programmed to know how much air can get in and might not understand if it’s getting extra.
Back in Ye Olde Times—carburetor days—the engine didn’t know anything, and just took whatever air and fuel it got and did things with it. Modern engines, depending on how they’re programmed, might not be able to recognize that they’re getting more air than they should, or that its coming in with a different flow pattern than designed, and they might not deal with it well. It gets really complex sometimes, and I’m not on the programming end of things or the hot-rodding end of things, so I can’t say for sure what the overall effects are; I can say that changing the K&N air filter with a paper air filter improved things until the computer malfunctioned [and that might be the subject of a further blog post; if it isn’t, assume that me reprogramming the computer ultimately fixed the truck].
Not exactly. In a nutshell, the engine has factory-programmed lookup tables for how much fuel it should inject for various operating conditions (matrixes), and the trim is how much it has to correct those tables. So 10% fuel trim would be a ten percent correction on what the table says it should do . . . for example, if the table said that in this condition, it’s supposed to open the injector for 1 millisecond, ten percent would be it learning it has to open the injector for 1.1 milliseconds (or 0.9 milliseconds; it can go both ways).
It’s a little more complicated that that in real applications, but that’s the basic gist of it.
I do indeed!
I have legit wondered the same thing. And I’m dreading the day when an automaker puts a beauty cover under a beauty cover, so it still looks good when you peel the first layer off.
5443386
I mean, aside from planting the corn and harvesting the corn and hauling the corn to market, then processing the corn and hauling the processed corn to market, yeah, it’s basically like solar power for your fuel tank.
AFAIK there’s some research in that direction. How far, I don’t know. And when we’re not addicted to oil here in the US, we’re addicted to corn. Take both those things out, and a lot of politicians won’t be happy with their donor dollars drying up.
5443416
Oh yeah, it’s hardly new tech. Fact is you could run a lot of the old engines on practically anything that burned; you might have to adjust the jetting and the timing but that was easy and sometimes had in-cab controls. Those engines were also fairly inefficient, and when you got to modern engine controls and materials, they got more sensitive to what went in them. Engines with catalytic convertors (for example) are really picky about what goes through them; you can easily destroy thousands of dollars worth of catalytic convertors in a few hours of driving if things get too far out of whack.
While I appreciated the robust, unkillable design of the straight-six in my old Chevy truck, it would never get more than 10mpg, and always had to be tinkered with, whereas my more modern minivan will go thousands of miles without even opening to hood to add oil or change the fouled spark plugs (I kept two sets for my truck, since in the wintertime it would only go a few weeks of short drives before fouling its plugs).
5443507
Waiting until I have the free time and right mental state to do it justice.
5443584
I could see that. There’s OBD-II reediness monitors, and I’d imagine for smog checks, it has to have no check engine light and have all the readiness monitors passed. And depending on operating conditions and other factors, it might take it a while to pass all those checks (sometimes you can make it do them quicker, sometimes you can’t).
Huh, that’s weird. I know about it, and we don’t even have emission checks in my part of Michigan.
Depending on what kind of tests they do, that actually makes sense. I know some places used to stick a probe up the tailpipe and actually analyze the exhaust gasses, but that equipment was expensive, so now they mostly use the onboard diagnostics to tell them if things are good, and depending on how the vehicle analyzes certain things, there might be some steps you have to take to make sure it passes its tests. For example, a lot of Fords do an overnight small leak test on their fuel system; theoretically, if you did a repair on a Crown Vic that was a taxi, it would never run the small leak test because it isn’t shut off for long enough.
5443630
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5443741
Because they weren’t mean to. Just like my grandma’s ‘63 Buick was meant to run on leaded gasoline.
That was legit a problem with fuel systems in the US as they put ethanol in the gas, and some cars that weren’t meant to have it had problems. Heck, I’ve got to put an additive in the tank of my older diesel Suburban (when it runs) ‘cause it was designed for high-sulphur diesel, and these days it’s all the low-sulphur stuff. And I bet if I had a modern diesel truck and I somehow got my hands on 80s diesel fuel, my modern truck wouldn’t like it very much, because it was never meant to run on something that was fractioned off, strained through a sock, and then sold to the customer.
Engine oils are the same way; what worked in my 70s Chevy (basically, anything slippery) might well destroy a modern engine that runs hotter and with much higher shear loads.
5443781
We sorta went through that whole thing in the early 80s with diesels, which were often ill-designed, rushed to market, and not ready for how customers used to gas engines would expect them to behave. And that’s why diesel cars generally don’t sell in the US. Flex does, but as often as not, the customer isn’t told that they have a flex-fuel vehicle; that’s just so the automaker gets a credit on their fuel economy ratings. Back in the late 90s, my dad got a killer lease on a flex-fuel pickup, which GM was leasing at a loss to make up for all the gas-hungry SUVs they wanted to sell.
Yeah, I don’t know the exact numbers on the actual cost of it (including environmental costs), but how you grow the stuff you turn into ethanol, how you transport it, how you refine it, etc., all factor in to whether it’s actually a better choice than regular gasoline or not.
Best choice is electric, but that depends on how the electricity is generated.
Same likely goes for American cars, to be honest. And that’s not the only material incompatibility issue; GM had a problem in the 90s and early 2000s with gaskets in the cooling system not being compatible with the coolant they were using. Well, they were as long as no oxygen got into the system . . .
Ford also had a problem in the air conditioning in the 80s and early 90s that was nicknamed ‘black death’; the liner of the hoses would dissolve and destroy everything.
Materials incompatibility is a real problem is the takeaway, I guess.
5444839 In a pinch you can test a sample of the fuel. Mix it with 1:1 with water. The ethanol will come out of the gas and mix with the water. However much more 'water' you end up with than you started with is the ethanol. Measure it and use maths for the percentage.
5445030
That was something I was curious about, honestly. It’s not as easy on this engine as some (gotta disconnect the fuel line, ‘cause there isn’t a Schrader valve), but I could. Between the incorrect baro readings and the code for a PCM fault, I focused more in that direction.
The customer says he fuels it up at a local station which doesn’t sell E-85, and we haven’t seen any other cars with fuel issues over the last couple of weeks, so the fuel is probably what it’s supposed to be. . . .
If it does come back still having issues, I will get a fuel sample. The customer might be lying about what he’s putting in the truck, or he might have neighbors who think it’s great fun to pour things into his fuel tank. I doubt either of those are the case, but of course I don’t know that.
5445500 I mean, he could be like the guy from the cabinet company next door to me, who filled the brand new 2018 Sprinter van with E85 - from dead empty all the way full, like 50 gallons or something. Shithead. We had to like coerce him to tell us what he did. He probably pulled up to the pump with the 'other' pump nozzle on it, and filled 'er up without thinking. I had to dispose of 50 gallons of diesel contaminated E85.
Which ultimately wasn't that big of a deal, cuz I just burned it all in my waste oil heater. But it was summer when it happened... although my dad wound up putting some of it in a random car because he was too fucking cheap to buy gasoline. That car smoked like a chimney and ran like shit.
5444857
Huh. Curious. I thought holding the pedal to the floor gave the maximum amount of fuel? It actually cuts it off entirely? Where did the idioms come from, then? And how does that work, if you don't mind me asking, in the mechanical systems?
Ah, thanks, and you're welcome. :)
Ah, thanks! That makes sense.
And good luck with that computer malfunction.
Ahh, neat! Thanks! And I'm guessing that these matrices can have many dimensions to account for many different tracked operating conditions?
:)
(Though it comes with hazards. The bit above, for instance, led to me doing a bit of research on mid-twentieth-century diode technology, then deciding that perhaps generating positive and negative voltages for alternator excitation in a system I've been toying with might not be best done with my then-current idea of a smaller three-phase alternator feeding a pair of half-wave rectifiers (each combining opposite halves of the three waves), and I spent some more time pondering using a pair of generators, with opposite terminals hooked to ground, instead. Then thinking about how, as I was already thinking of having the excitation alternator driven by teeth on the flywheel and the battery charging alternator/generator on the other side, I could instead have the two excitation generators on opposite sides and move the battery charger to opposite the air starter, also using the same teeth. And then I wondered if it might be good to mount the excitation generators on the bottom and the air starter and battery charger on top, rather than the reverse as I'd been thinking, since the excitation generators would likely need more frequent maintenance due to their commutators and harder use. And I really didn't have time for any of that, just like all the other interesting things I've been distracted by today.
Oh well.
Not like I've never had this happen to me before; thanks for, in addition to direct education, sparking some interesting thoughts... even if this was once of the many case where they were inconveniently timed. :D)
:) again.
...Maybe it's for investors? Like, the engineers already know what it looks like, the mechanics need to get in there, the owners who don't want the engine seen already have the hood, and the owners who do want to show their engine off seem pretty likely to want to show off the stuff under the beauty cover, too. But some of the investors might want to see the engine while not being the sort of people who actually want to see engines, or maybe even know how they work, and just want to see that the engine they're paying for looks cool and high-tech and likely to give them a good enough return. Hm, actually, some car buyers might also fall into the "determined to see the engine and more likely to buy the car if the engine looks cooler, despite not knowing much about engines or that the part that makes it look cooler actually just makes it more of a pain to maintain".
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I’m so glad that two of our customers who filled their diesels with gas told us exactly what they did. One guy was smart enough to not even try and start his car; he had it towed from the pumps to our shop, so all I had to do was drain the tank, put in diesel, and it was fixed. The other, I don’t know if they started it or not, but it was an old 7.3 so once again no big problem. They balked at the price a bit until I reminded them that part of the price was a full tank of diesel to soak up whatever gas we hadn’t gotten out of it.
I’ve run two-cycle in an older truck (it burned oil already, so a little bit more wouldn’t hurt). That first one we drained the gas/diesel mix out of? I took five gallons home to use for firestarting, which was interesting—sometimes it would flash like gas, and other times it would burn slow. (Also, not recommended; I read a NTSB report about how the difference between the fuels might make a mix spark themselves and then ignite, which is really bad when it’s a storage tank at a tank farm.)
One day some bastard stole it. I wasn’t mad about the fuel going missing, but I was upset that they took my gas can. The only solace is that they probably poured it into their car—it smelled like gas—and if they did, I bet their car didn’t like it much.
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I think, although I don’t know for sure, that in old carbureted engines, holding the throttle plate all the way while cranking minimized engine vacuum, and thus minimized fuel it pulled in (since as I recall, that’s pulled in by a venturi, and no vacuum means no pull). Which, if I’m right, is why they’d keep the same technique to clear a flooded fuel-injected engine.
[Somewhere I’ve got a driving book from the 50s which might say, and I’ve also got owner’s manuals for carbureted cars; I’d have to go digging to find them, though.]
Yeah, back in the early days you might have had engine load, engine temperature, air temperature and pressure, and RPM; obviously, these days they track a lot more and control a lot more. Some computer guys might also refer to them as ‘lookup tables,’ and I’ve also heard of them referred to as ‘load cells’; the idea is that you can save on processing power if you’ve already told it what it should do for theoretical conditions, and then just stick a modifier or two on it for real-world conditions.
Some of our training classes have covered a tool which kind of interacts with them, and shows if it’s got good fuel control in various matrices. I’d have to really do some hunting to find that on the internet, though.
Been a while since I took a course in how alternators actually work, but from memory, they’re triple-wound, and produce three offset AC waves, which are then run through a Y-bridge (of diodes, I assume) to flip the negative waves to positive so you kind of get a lumpy 14ish volt output. I do know that most of them nowadays are computer controlled to feed the battery what it wants, and a lot of them have clutches in the pulley to unload the belt drive sometimes but I don’t know exactly how that works.
I also know that some of GMs mild hybrids had an alternator that could also be powered to turn the belt and help out and/or start the engine instead of the starter, but I’m not entirely up on that system except to know that they shred belts and belt tensioners.
It happens to all of us, lol
I think for the most part it’s for the buyer, since typically the more luxury the car, the bigger and shinier the engine cover, makes it look futuristic, you know. Instead of a boring internal combustion engine with an intake and wires and stuff. Some of them also have insulation to help mute the engine noises, which you can also do with the radio (IIRC, Honda does this in some models).
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...Granted, I am pretty tired at the moment, but I'm currently wondering if this is how you felt when faced with a valveless opposed-piston two-stroke diesel, sorry. :)
(Maybe it'd help if I looked up some diagrams, or something... some time when I'm less both tired and busy...)
"[Somewhere I’ve got a driving book from the 50s which might say, and I’ve also got owner’s manuals for carbureted cars; I’d have to go digging to find them, though.]"
While I'm still curious, please don't trouble yourself too much on my account. :)
re the lookup tables:
Ah, thanks. Neat.
re alternators:
Ah, at first I was confused, and then I realized that you were talking about automotive alternators specifically. Interesting! I didn't know that they were mostly three phase (or that's what it sounds like, at least). As I was just the other day thinking of using a three phase alternator to reduce post-rectifier ripple, that makes sense.
(I had some trouble trying to look up what exactly a Y-bridge was, though. Do you know?)
Anyway, thanks; neat, this, too. :)
"I also know that some of GMs mild hybrids had an alternator that could also be powered to turn the belt and help out and/or start the engine instead of the starter, but I’m not entirely up on that system except to know that they shred belts and belt tensioners."
Ah; that seems like it'd be a problem. :D
...I wonder why they didn't fix that?
"It happens to all of us, lol
"
:)
re beauty covers:
Ah, yeah, that makes sense; thanks.
(Though by "radio" I assume you mean the unit that's just a radio in the way a modern smartphone just makes telephone calls, not somehow the actual radio-radio?)
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Yeah, kinda
Illustrations or even better a YouTube video explaining it often helps. That having been said, I’ve watched some YT videos about how valveless opposed-piston diesels work and I think I know but I’m not entirely sure I fully comprehend. . . .
I took a quick look and didn’t find it; I’ll try and file that in the back of my mind for the next time it shows up.
re the lookup tables:
Ah, thanks. Neat.
This may or may not be helpful:
lh3.googleusercontent.com/proxy/86SBWrw_-nopgBjmq_PRNWOHcqRQQilFpxBDuJZFPiEytYJ-X9AkaE7Py_70IYKwhobgdX6YswgkD3_bRSczWdAhyNqnr_wdKRUWDVKh49JS2C7REZ_dXZT1p6Pz7jmJBciBWP5FiwE01q0r6IdXVO18NE9_Dg
In the world where I work, we don’t rebuild alternators, so our only diagnosis is if it’s charging like it should or not. So I’ll admit to a lack of familiarity to what’s going on inside the thing (or not, as the case might be). That’s one of those things where I ought to spend a little more time on theory, but for the most part I can leave that to the engineers, and instead rely on comparing what it ought to be doing to what it’s actually doing.
Modern computer-controlled alternators are slightly more complex, but only slightly. The only wrinkle is that instead of doing things on its own, the computer tells it to do a thing, and it either does or doesn’t. As long as the wires are good (it sees what the computer tells it) and the commands are sensible (the computer didn’t go rogue), I can fix a car with ‘something went wrong inside the alternator’ and leave it at that.
My guess is that they didn’t anticipate what would happen to the belt. Probably did okay in field tests but not so well in the real world.
GM isn’t as nice as Ford when it comes to part revision (GM has an eight-digit part number, and what you get is what you get. Ford has an eleven-digit number [usually]; the first four tell you what model car it goes on, the middle five are what part it is, and the last two are what revision it is. AA for original design, AB, AC, etc. for minor redesigns, BA, BC, etc. for major changes. So you get something with a part number ending in -CB [for example], and you know they struggled making it work.) so we never really know. Sometimes computer updates give us clues, but mostly we fly blind.
It is the radio-radio, it has a function like noise-cancelling headphones: it uses a microphone to pick up the ambient noises and is programmed to ‘mute’ some of the engine noises even when the radio isn’t on. I’m not fully up on exactly what they do with it; it was one of those things that came up in a training class briefly. The gist is that one of their engines is a six-cylinder displacement on demand engine, where they save fuel by skipping three cylinders when it’s in light load. The downside is that sounds weird. GM used overengineered mufflers on some of their DOD products, while Honda (or Toyota, can’t remember) used the radio to cancel out the odd engine noises when their V6 becomes an inline 3 for efficiency.
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[shrugs]
Do you have any suggestions for what good search terms might be for the... system, if/when I get around to it? Though I suppose it might just be good to look into carburetor design in general; that seems like it'd probably get to this question at some point, and I imagine that there'd be a variety of other interesting information along the way. :)
[shrugs again]
Well, thanks, and good luck!
"re the lookup tables:
Ah, thanks. Neat."
Was that supposed to be quoting me saying the same thing? If not, I'm not sure what you mean, sorry.
...I'm afraid I'm going to have to go with "not", there, though I'm guessing that a box displaying "Upstream error" was not the image you meant for me to see.
I do not know why some images on FIMFiction seem to be broken that way while others aren't...
Anyway, though, do you have another link, or some way to fix that? I'm curious not only about the topic but about the particular image you meant to include. :D
re not rebuilding alternators:
Aye, fair enough. You work has to start treating components as black boxes at some level of disassembly, after all.
"I can fix a car with ‘something went wrong inside the alternator’ and leave it at that."
I mean, I assume you do also have to put in a working alternator, though, and not that you actual have Magical Mechanic Powers that allow you to fix a problem just by roughly identifying it. :D
...Hm. I wonder if there's a story in a magic user (a unicorn?) working at a repair business and able to fix things by just diagnosing the problem precisely enough for their version of Mend to be applicable, but for some reason having to hide this and come up with stories of more "conventional" repairs.
(Note that I'm not actually accusing you of secretly being a Pony Repair Wizard, as cool as that might be, even if that notion from the phrasing is what led to the idea above. :D)
"My guess is that they didn’t anticipate what would happen to the belt. Probably did okay in field tests but not so well in the real world."
Ah, that seems plausible, depending on what sorts of testing they did. Still can't test for everything, though.
re part numbering:
Oh, neat; thanks.
Though I can see how the GM situation would be difficult for you there, yeah. I can imagine situations where you know that there's a version that works and multiple versions that don't... and it's extremely difficulty to tell which any particular example of the part is.
(If I'm understanding you correctly here, at least.)
How do the computer updates give you clues? ...Though I think I may very vaguely recall that being mentioned once somewhere in your blogs...
re the noise cancelling:
Oh, interesting; the function being some sort of active noise cancellation is what I thought you were talking about, but I still don't see how that's done by the radio-radio; from the more detailed descriptions, I'm now guessing that we have different categorizations for what counts as part of the radio-radio.
(I, for instance, don't think I'd include the car's speakers, or CD or tape player, or the like. The audio controls, maybe. But mostly just the parts actually related to pulling radio waves out of the air and then converting them to whatever signals need to get sent to the speakers to produce the desired sounds.)
I'm guessing that you think of the radio-radio as that whole car-audio-system-console-mounted-central-unit thing, but I'm now wondering what's related to that that you don't classify as the radio-radio. (...And also what the proper name for that car-audio-system-console-mounted-central-unit is. :))
re the displacement on demand technology:
Oh, cool; I don't know whether I knew that was a thing. Thanks! :)
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For carbs, you could start simple with a lawnmower carb or something like that and then work your way up to automotive one-barrels and then four-barrels. Like, at their most basic they’re a flap to control the air and a metered orfice to suck some fuel into the intake as the air rushes by.
That was me being careless in the reply
I should have checked that before I hit reply, or put a link in case that happened.
picoauto.com/images/uploads/case-studies/atl_wiring.png
Try this; here’s the link to the article it’s in.
Yeah, although sometimes the automakers give us not enough to work with. I’d like to know what the black box does, even if I can’t fix what’s inside it. That’s why you’ll occasionally see pics on my blogs of a computer pried open and a picture of the melted guts.
That is true.
I wish I was a repair wizard. Sadly, sometimes like on the Cadillac that needed a priest, I do know what’s wrong but then there’s the matter of fixing it.
Actually, speaking of that Caddy, I ought to write a follow-up. It only needed a starter, and the weird stuff it was doing is weird stuff it was programmed to do, but I didn’t know that because hitting the start button was a black box of sorts.
Yeah, you’ve got it right. Sometimes if it’s a major, major change, they’ll give it a new part number (so you don’t get an old one to put on), but if it’s a minor revision where one’s better than the other, there might be no way of knowing.
On GM, they’ll show you what software version it has and how many updates off that there are. Their update numbers are also incomprehensible to me (it’s not like it’s v1, v2, etc.), but if there’s the factory calibration and then five uninstalled updates, you know that they had a problem.
GM will also often tell you what that addresses; on the horrible inline-5 Colorados and Canyons, when I worked at the dealership there were already three updates to address a rough idle. None of them fixed it, because the problem was GM couldn’t make an inline-5 that didn’t vibrate.
For the sake of discussion, when I say ‘the radio,’ since I’m usually talking to people who aren’t familiar with automotive stuff, I mean a blanket ‘everything radioish’. Like if you imagine a boombox, all the things that it does I’m considering the ‘radio’ Because:
You’re actually right on the money. The Caddy that didn’t need a priest after all has the Radio and also the Digital Radio Receiver (the guy who gets the signals), and it might have a separate disc changer or touchscreen, and if it had an amplifier as a separate module, the speakers would do what the amp said based on what the radio said (or the DRR)
That really depends on the automaker. I couldn’t give a sane answer. That’s the one problem with working with lots of different auto brands; GM might call the instrument cluster the instrument panel cluster (IPC) while Ford calls it the hybrid electronic cluster (HEC) and Chrysler calls it the gateway . . . the Caddy had an IPC and an IPM (instrument panel module) which as far as I could tell from what it did is a re-named body control module . . .
Yeah. Nobody calls it that in marketing, ‘cause Cadillac had Displacement on Demand in the 80s and it was terrible, so now it’s “Active Fuel Management” or some other marketing buzzword. But it’s the same idea.
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...Ah! Mostly just from your description and some things you said earlier (well, and prior knowledge of general related physics and such), I have a hypothesis: the piston-- wait, no, that wouldn't work for two strokes, and I know there are two stroke engines with carburetors. Hm. Well, still might be mostly right... Okay, I am tired and in a hurry again, but it looks like this time my curiosity is overwhelming my drive to keep moving through my queue (and towards the close-ahead "nap"). :)
[researches a bit]
Interesting; clever device, looks like. :)
I mean, I'd definitely not call myself an expert, and might research more at a later time, but I think I've now a better understanding than I did.
...I'm still not sure exactly how the flood clearing works, though. If anything, I've more just gotten a better understanding of what the complexities I don't know are. And possibly there are just still some things I don't understand so much that I don't understand how I don't understand them. Hm. Oh well. I don't have time to keep looking right now, though.
But thank you for your efforts to explain; I do think I know this better now, at least, from what you've said and the research you spurred!
Ah, righto; no problem, then. :)
Heh, no problem. And that image works; thanks!
And thanks; I was able to puzzle out how I think the system in that works. :) (Though I'm not sure why they used nine diodes instead of a different configuration I thought of using either, while trying to figure out how that worked, so I suspect I may still be missing some detail(s).)
(Though thank you for the link anyway.)
And as for the Y in Y-bridge, I'm guessing it refers to the system using a Y configuration instead of a delta configuration, looking at that diagram.
Ah, sorry about that.
"That’s why you’ll occasionally see pics on my blogs of a computer pried open and a picture of the melted guts."
...I don't think I follow they why there, though, sorry.
Yeah, thought so, but thanks for the confirmation. Oh well. :)
"I wish I was a repair wizard. Sadly, sometimes like on the Cadillac that needed a priest, I do know what’s wrong but then there’s the matter of fixing it."
Aye, sorry.
"Actually, speaking of that Caddy, I ought to write a follow-up. It only needed a starter, and the weird stuff it was doing is weird stuff it was programmed to do, but I didn’t know that because hitting the start button was a black box of sorts."
Ah, topical, sounds like. :D
(And I see that that blog post appears to be already up.)
Ah, well, thanks for confirming I was right there, but sorry about what I was right about. That does sound potentially very annoying.
Ah, thanks.
Yeah, if the hardware is bad enough, software updates aren't going to be able to fix it.
(Was the vibration the only thing that made those particular engines "horrible", or was that one of many problems?)
re What Is A Radio:
Ah, thanks!
(What's the difference between the Radio and the Digital Radio Receiver, though? Both connected to the antenna, both receive the same signals, but one converts analog signals to sound and the other digital? Or something else?)
re the names:
Ah, heh, sorry. :D
(Though is the instrument cluster not the cluster of gauges and such right in front of the driver, rather than the cluster of equipment in the center console? I mean, apparently not, but I thought it was, I think.
Oh, and are the climate control controls included in the Cluster Of Many Names, too?)
Ah, heh. Well, thanks. :)
(I don't know if I'd heard of "Active Fuel Management" by that name either.)
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I would guess that with the throttle plate wide open, there isn’t sufficient vacuum through the carb to pull in fuel, but I don’t know for sure.
Ah, righto; no problem, then. :)
Yeah, I don’t know. I remember learning that alternators had a Y-bridge in them but I don’t remember why. And I don’t know why they use the diodes like they do, either. I do know that modern alternators are different than old alternators, but I don’t know how different.
Oh, to peel back the lid on the black box and see what went wrong (if it’s visibly wrong, like a part melted).
Mostly the vibrations. Five-cylinder engines aren’t naturally harmonically balanced, and while the Europeans have figured that out and make some smooth-running inline fives, GM did not.
In the above case, the radio is not connected to the antenna, that’s the Digital Radio Reciever’s job. Who then sends the signals it got to the radio for further processing. If I ever get bored at work, I’ll look up the network diagram for a late model luxury car and see how many different modules do ‘radio’ things.
Yes, the instrument cluster is the lights and gauges in front of the driver. The cluster of equipment in the center console is generically the center stack, and depending on the year and automaker, will typically have the radio and HVAC control head in it, and possibly some other stuff. I think on late-model F150s there are at least five modules in the center stack, maybe more. There’s the radio, the FCIM, the HVAC (which they might still call the EATC), the screen (which I can’t remember the acronym for; I think it’s the FCDIM), the APIM . . . possibly the media hub, too, although I can’t be sure because although I’ve seen it mentioned in Ford documents, they’ve never clarified what it is or what it looks like.
Of course they are. HVAC on GM, EATC or HVAC on Ford, Lord knows what on a Chrysler (anybody who had modules named WIN and SKREEM shouldn’t be allowed to name anything). And like everything else, they’re not the only game in town. HVAC module needs to ask the engine control module and maybe the body control module if it’s okay to turn on the air conditioning, and if you’ve got heated seats, those might actually be controlled by a seat module (and might need permission from the body control module, too, if that’s who handles battery loads). Or if the buttons are on the door like in some older GM SUVs, it’s the door control module who processes the request.
Sometimes finding out which modules handle the request is the biggest hurdle. Or who has the information. Like, on a minivan like mine (2007 Dodge Caravan), it’s the fuse box that knows the outside air temperature and tells the other modules.
There are probably other marketing terms for it, too. I have no idea. I do know that GM, Chrysler, and Honda (or Toyota) all have engines that do it.
If I drink a beer before heading out my bicycle also runs on alcohol.
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And maybe that's true when it's being cranked by the starter, but not when the engine's running and things are moving with more speed and force, and the pull is stronger, explaining why the system doesn't cut off fuel when that happens later on?
"Ah, righto; no problem, then. :)"
...Did you do that deliberately? :D
[shrugs]
Well, I'd guess you still know more than me here, but it sounds like it might not be by that much in this particular instance. Oh well.
Ah. :D
Thanks.
Thanks.
(Do you know what the Europeans did there?)
Ah. :D
Well, thanks. :)
Ahh, okay, so you were just using the instrument cluster as an example there, not saying that that was actually the collection of controls and displays on the center console. Sorry about the confusion.
And thanks for the information!
What are the FCIM and APIM, though? Sorry if I'm forgetting.
re the Mysterious Media Hub: Heh, sorry. :)
Hah, wow. Thanks. :D
...Why is it the fuse box in charge of finding out and disseminating the outside air temperature?
Neat; thanks.
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That’s a reasonable guess. I don’t know for sure, though.
No, just that I’m sometimes bad at cutting/pasting/tagging
Especially on longer replies.
I don’t, honestly. I’d assume both better engineering and more practice. I suspect that most of the European inline-fives are designed that way from the ground up, whereas GM took an inline six and chopped a cylinder off the front. Probably has a different crankshaft, but other than that AFAIK it’s fundamentally the same as the I6 and I4 in that engine family.
Correct. And to be really pedantic, the instrument cluster would generally refer to the one that had the speedometer in it, since some vehicles have separate gauges or warning lights which would likely have a different name in the service information. For example, my Oldsmobile has only a speedometer, odometer, and fuel gauge in the ‘cluster,’ and then above the radio and HVAC, it’s got a bank of warning lights.
Forward Control Interface Module (basically, the center stack buttons and/or screen) and Accessory Protocol Information Module, IIRC (SYNC [Ford’s trademarked name]/the thing you plug your iPod into). I’ll be honest, I use generic terms a lot because the scan tool does and because it’s nearly impossible to remember what each automaker calls each module.
My guess would be because it’s ‘smart’ (i.e., on the network), and because it’s geographically closest to where the sensor is, so it’s cheaper to run a short wire to it instead of a longer wire to the PCM or the BCM or whatever other module. As automakers have gotten smarter with networking, there’s a lot of that—usually the tire pressure monitor is attached to the keyless entry module, since the RKE module is set up to receive radio signals, and that’s what the tire monitors give out. Why add a whole new module when you’ve already got one who can do the job?
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Well, thanks.
Ah, hah, righto. Funny place to have it happen again, though. :D
Ah, thanks. Yeah, that sounds like it could make a difference.
Thanks.
And interesting; thanks.
And thanks. :)
And thanks makes sense! Thanks. :)