08 corvette e38 ecm maf disabled causes stumble after start.

as the title says, when I fail my maf to tune map, it cranks and starts normally, does the rpm flair but then stumbles and almost dies. it mostly does OK after that, but sometimes clutch in coming to a stop the rpm drops low enough the steering gets harder.

not a issue tuning maf, but I have a air intake that causes turbulence and surge at light throttle cruise at 70 and I'd just run it on SD if it wasn't for the start and idle issues it causes.

I thought I've read the maf isn't used at low air speeds, but mine definitely effects it, does anyone know how the ecm uses the maf in the code during idle and just after crank? I'd love tune this out and run SD. I've searched every keyword I can think of, but no one seems to talk about what I'm seeing.

Do you have MAF Fail Timers in that tune? Should be right in the same area as MAF FAIL HZ. Set them to 0 if you do, default may be 1 or 2. I say this since I had the same problem with a 2010 LS3. MAF would fail after 1-2 seconds runtime, but until it failed, it would only run off startup fuel/air which is what the flair is from. The flair would end right before the MAF would fail, and it would almost stall, once the MAF failed then it would idle back up and run normal.

I'll check that tonight. I did catch a thread or 2 about that but since I has a random stumble while coming back down clutched to a stop, I kinda disregard it. but I'll try it out. maybe it some how. looks at the maf again on its way down.

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Originally Posted by ???

I'll check that tonight. I did catch a thread or 2 about that but since I has a random stumble while coming back down clutched to a stop, I kinda disregard it. but I'll try it out. maybe it some how. looks at the maf again on its way down.

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oh, you mean while driving. Your post made it sound like after start. "it cranks and starts normally, does the rpm flair but then stumbles and almost dies. it mostly does OK after that,"

The two issues may be separate and unrelated, or the same problem. lol

yeah, it definitely does it when cranked the worst but also has low idle randomly, not always and you can't really tell unless you're looking at the tach, mostly just the ps gets stiffer at all the wrong times haha, so yeah, could be linked, might not be. I will try for sure, even solving the cranking part would be sweet. I can probably work around the other part if it does it still.


thanks

Have you tried increasing base running airflow? Could be low. Add 10% see what happens, keep adding 10% a few times see what happens.

I haven't messed with airflow settings at all, since this is basically a stock car, which I forgot and left out of the first post, only thing it has is a air box and a slightly freer flowing exhaust, I was leaving everything else alone in search of this issue. but if the delay setting fixes the first start stumble, then I will do that to see if it fixes the 2nd part.

the area scaler tables come more into play when the maf is failed and they usually need adjusting to help, main one is the max fail 60 change that to 200 see if it helps

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Originally Posted by 07GTS

the area scaler tables come more into play when the maf is failed and they usually need adjusting to help, main one is the max fail 60 change that to 200 see if it helps

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are you talking about ETC area scaler? mine is step to 4,725.000 stock.

my max fail is 200 already and min fail 5. should I go up to say 260 and try that?

thanks

just to follow up, going from 200 to 300 plus doing the delay to 0 from 1 and it's perfect now. looks like it could use some more tip in ae from watching the wb but you can't really feel it driving. smoothest it's been since I got the car.

now to put the ram air duct back on and do some ve tuning for wot.

thanks again. honestly would have never tried that on my own.