trans problems related to maf help please

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Originally Posted by airdeano

MAF has a direct effect on shifting. your shifting problem is light throttle
or just WOT throttle?
check to verify the wiring to the MAF is not damaged.. did you get a MIL
when it was unplugged? or have you always had a MIL on?
DTC 101-102-103 are MAF codes plus you should have had some IAT DTC.
the MAF also contains the IAT (intake air temperature sensor) unplugged
the computer thinks its -40° intake air... fuels and timing accordingly
seeing as your disconnected the cables (incorrectly) you now probably
need a transmission relearn as well as a full system relearn.
try this procedure...
disconnect the negative cable (only) lead from battery
disconnect any and all cell phones from the cig lighter jacks
press the horn and brake pedal for one-minute or longer.
reconnect the negative battery lead to battery.
youll need appox 200mi to relearn all the adaptive learning sequences

airdeano

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This is good info, My truck always ran better when it was warming up. So now I see why I was told to disconnect the maf. :nono: fool it into thinking it was cold only its humid 100. Thats a few pieces of the puzzel.
I got no MIL or codes at that time nor have i since. I did get a chance to speek with Allen ( what a great dude ! ) and there is no way of knowing what was turned off in that tune so Mil or Mil means nothing without knowing.
Shifting problem is at any throttle I must back off the gas the for the trans to upshift. but 30% throttle(guess) at any speed down shifts trany to first and reves the motor like your foot is in the radiator. BAMM that fast bounce of the rev limiter. That's scary since the rear wheels are connected to the phsyco drive train.

I cleaned the Maf yesterday no change the Poss cable off all night- not been out to check yet, but from what this post says, That is incorrect so I haven't been in a hurry to find out it didn't work,

The relearn proceedures (that take 200 mins) is there a link or site that I can go to to study them, then I can learn all the adaptive learning sequences. I did a search but not to much luck, Lots of info On CASE learn but i dont know if that is just v-6??

My truck is a conversion trans plant so if the horn and brake have some thing to do with BCM and other electronic wizardry I dont have it. May be its so you take a ONE FULL MINUTE sitting in your broken truck to realize how much you appreciated it when it was running, well that will work. With the propper cable removed of course.

Thanks to all

The transmission problem sounds like a common one that many guys with a larger than 3000 RPM stall face, P0757 I think it is. You have to program the PCM to fix it. Allen is very familiar with this issue. I'm not sure how he fixes it but he's fixed mine.

Finally some good news, Allen will send out a new computer monday,
Left the positive off all night , No change. no code no light,
Thanks guys, Ill let you know if the new computer fixes it, or if i broke someting What an a$$ ache!!!!!!!!!!!!!!!!!:whack:

no DTC's... interesting.. was this first setup to use MAF?
i know before i converted to SD tuning, if i removed the MAF, but left
the wiring connected (IAT still functional) if get a P0101 or 0102.
do you have a MIL setup? usually also a P1870 FMC error occurs as the
"load" isnt complete so default full force (bang) shift to protect from
slippage. id get a stock no vats tune (leave the DTC's alone) to verify
issues.. and run the DTC's out in batches.

airdeano

Quote:

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Originally Posted by airdeano

no DTC's... interesting.. was this first setup to use MAF?
i know before i converted to SD tuning, if i removed the MAF, but left
the wiring connected (IAT still functional) if get a P0101 or 0102.
do you have a MIL setup? usually also a P1870 FMC error occurs as the
"load" isnt complete so default full force (bang) shift to protect from
slippage. id get a stock no vats tune (leave the DTC's alone) to verify
issues.. and run the DTC's out in batches.

airdeano

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That is exactly Allens plan. 99% only tune for the mods that I have so that it will run, I guess a proven tune file that he knows is good. My mods are pretty mild and common. CAI, shortie headers, cam,spring p rods & shift kit / stall converter to match.

The ony time I ever got a bang shift or code was when the vss wire got pinched.
That was also interesting, because without the vss input that truck had so much more power, LOTTS more. It wound up pretty tight shifted hard (bang)
into third and stayed there. no down shift no tc lock. Shut it off....start back in first... repeat.
You could leave a stop in third gear no problem. But the increase in power off the stop in first gear was dramatic and also in third. I fixed it asap, but always wondered why it was so strong only then.. and not always... obviously it was/is capable.

so ???? no vss signal.. truck has more power????
and???No maf signal.. truck has WAY more power. (its gonna break the seat mounts) starts better, idles smoother.:eek: WTF I dont understand how its running at all. :duh:

I"m guessing that the file that is in the pcm now is junk or at least way way wrong for my truck. And the truck is a lot stronger than I thought. I can not imagine how great its gonna be when its tuned right. This bi polar electronic stuff has got to go.
I drove it with this tune for 18k miles and no issues till the other day, My buddy drove a brand new company pickup with a 5.3 , I let him use my truck to move and he could not believe how much better mine ran than the one he drove for months, he's a gearhead so he knows. Wait till i tell him my rig's been running like shit since i put it on the road.

Any new news on your shifting problems? I'm running into the same thing w/ my swap. Shifts fine at normal but WOT the truck just red lines and won't shift. I'm getting the p1870 code though. Just wondering if your new tune fixed it?

JBR, check this out... P1870 Trouble Code; "Transmission Componet Slippage" - Automotive Message Forums

and this ... My3cents.com - General Motors Informative - GM service bulletin about code p1870, GM service bulliten about code P1870

Red,
I've done the normal search for the code but I think I remember reading somewhere that the code can be kicked by a tune that's not right on the money. I could be wrong..... It's just something I read. New news on the truck though, I went for a drive today and now the trucks dead on the side of the road. It was driving fine down the highway and then nothing. Park works and every other gear is like neutral. At 1st look it's like the trans pump went out, like there's no pressure in the valve body. Now I'm wondering if a tune can be out far enough to kill a trans? I guess I'll be pulling that apart this week. Good thing I have vacation time saved!

I don't know about the tune crapping the transmission out. The first indication was you have a bad valve body. It could have killed the transmission. How many miles did you have on the transmission?

Quote:

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Originally Posted by duckmanjbr

Any new news on your shifting problems? I'm running into the same thing w/ my swap. Shifts fine at normal but WOT the truck just red lines and won't shift. I'm getting the p1870 code though. Just wondering if your new tune fixed it?

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Several things have happened, I got my new tune from Nelson Performance and that did not solve the shifting problem , the truck performs better, pulls very hard, bit will not shift properly, Different Maf minimal change and new problem.
At a normal driving part throttle (no let up) It will only shift out of first at well over 4000 by it self.
It will shift to second sooner if I let off the gas.
It seems to shift 2-3 & 3-4 a bit high rpm but reasonable , much better if i let of the gas , drive it like a stick shift.
Down shifts back to first at 20mph.
Wot from a stop- good launch, pulls hard, red lines, bounces off the rev limiter no shift till I let off the gas - some times right to 3rd
Wot from the speed limit - down shift to first , pulls crazy hard till redline, no shift.
Definitely not slipping.
Running, starting, idling, cruising, all better & pulling harder with new tune
I spoke with Allen and he said to substitute a KNOWN good MAF and try that.
I BOUGHT ONE FROM A BONE YARD (bc i couldnt find a donor) not a KNOWN good one. and I still have most of the same problems, and a new one.
Hard to start. but the 2-3 3-4 shift is much better. that was today 8-23

So IDK WTF. other than my wallet is 50 lighter.

Keep in mind that I had ZERO problems with this truck ((other than only minimal performance gains based on the mods I have)) till I unpluged the MAF.

I thought and correctly that the truck should have more umph. Per opinion of other person, I unplugged the MAF, for a diagnostic check. Based on the results, They also said leave it un-pluged. The truck really came to life, had fun for that day and now just A$$ ache.