BAD BLACK WS6

well guys, here is the deal. i know it may be something everyone asks, but i am getting to know the TPI all over again with this new 3rd gen. seems the car stumbles and shuts off sometimes at idle in drive. you know, right as it deaccelarates to 0MPH at the stoplight. starts to stumble and dies most of the time. if its in park or neutral it will idle forever w/ no problem. and at cruise or WOT it runs fine, no hesitation. any ideas? similar prob on my LT1 and it was a shorted out MAF (fuse blown). not sure if it may be the same here? looking to find out possible culprits to help track it down. very annoying problem since it shuts the car down. thanks.

PETE

iTrader: (1)

check to see if the ses light comes on before it staalls if it does there is a code in the computer retrieve the code look it up it will give you a starting point to help diagnos the problem

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87 trans am 350 L98 aluminum heads,LT4 hot cam,slp runners,headers,y-pipe,edelbrock base,hi flo cat,air foil,ported plenum,t-5 tranny w/centerforce clutch and a 3.27 9bolt,ads strip chip,relocated iat sensor,hollowed maf

14.10@97mph w/2.01 60' LOOKING TO TRADE?ANYONE

BC86TPI-Z51

My 86 Did this a few years ago...dang MAF sensor was going bad...I also suggest to change the relays anytime a MAF is replaced.

This is also very easy to check with a scanner sometimes..especially if the ecm isnt throwing a code yet.
I watched the IAC counts and the MAF gps on the scanner and seen what happened when the car went to stall.
I also was able to see what the TPS voltage was and etc.

I have a suggestion to try...unplug the maf sensor wire and tie it out of the way...start the car..it may take a few tries...drive it down a empty street for a few miles and come to a stop several times..if it no longer stalls on you or acts up as you described you may be onto something there with the system.
The car wont run that great with the MAF unplugged but it will still run..it will aslo set the check engine light...after you plug the maf back in, disconnect the negative battery for a minute to erase any codes.
I did this before when the MAF did what yours was doing..first it started to stumble and stall at slow downs and idle...then it got worse and wouldnt start up or run...unplugged the maf and it got me home.

Just dont go out and buy all them new parts until its all tested first..them things aint cheap eh?

bjankuski

I would suspect your minimium idle speed is set to low. There was a service bulletion from GM on this problem. The car should idle at 450 RPM in drive with the IAC in the closed position. If the minimium speed is set too low the car will stall at stop lights after it has been running on the highway at a sutained cruising speed. What happens is the car pulls up to the light and the IAC does not respond quick enough and the engine dies. To fix the problem you need to find the article in the tech section on minimium idle speed procedure.

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1988 Formula 5L/5sp 3.45 gears, SLP cold air kit, MAS gutted, TPIS air foil, TPIS AFPR, MAC headers, Mac under drive pulleys, MAC cat back, Relocated MAT.
Best ET street tires 13.85
Best 60 FT street tires 1.930
Best MPH street tires 99.29

Velocity

Not sure, but you might check the IAC valve. I had a problem similar to this and it turned out to be the idle air control. As soon as I changed it out, everything ran gorgeously, and its a butt load cheaper than an MAF.

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'87 GTA
Automatic 350 TPI
2 3/4" Flowmasters
K&N filtercharger
4 3/4" Glasstech Cowl induction hood
TPI intake air foil

Coming Soon...
Hmmm...Perhaps a new bird...pro street????

System:
Panasonic DFX-99
2 12" RF DVC's
RF 250.2 (Custom
RF 200.4 Painted)
Sony 10 disc changer
Clarion Pro Audio 4x6's

BAD BLACK WS6

thanks guys. one thing: WHERE THE HECK IS THE CHECK ENGINE LIGHT ON A DIGITAL DASH!!!!!!!!!!! i am lost. i know its location on third and fourth gen dashes, but not the digital. i figure i would see it if it lit up.....but it may NOT be lighting up. funny enough thing is, it does idle sort of low. looks like under 400RPM, again hard to read the digial dash for precise readings. I will try to figure it out precisely to see the true idle. so i suppose it could be the idle/IAC problem OR the MAF problem. the guy who sold it to me was harping on the MAF was replaced. mentioned it several times for no reason. maybe he was hinting that he didn't replace it and it needed to be replaced. people do that for some reason instead of being honest. not sure, really weird guy. toughest part is that i hide the car at work, cause if i brought home a third car i would get lynched! (i got a '96 LT1 WS.6 and a '80 TA, both modded out the ying-yang). so its tough to "check" it out since it sits at work. but i will be able to bring it home next week all week, so i will be able to spend some time diagnosing it. as for the article mentioned, i can find it in the tech section on this board i assume? thanks again.

BAD BLACK WS6

also.....again i don't have the car here....is the MAF inbetween the air induction system and the throttle body like on the LT1? or is it placed elsewhere. i remeber looking at the TB, and don't remember an MAF in front of it. but i may be wrong, i was after all dealing with the cooling system at that time. if anyone has a good overview pic of the TPI, that would be appreciated. thanks.

BAD BLACK WS6

figured it out after opening the hood to replace a dead battery this afternoon. seems someone decided not to connect the air box above the radiator the the ribbed piece that connects to the TB. can you say massive vacuum leak! it was loose, and the right jostling pushed it looser and the car would start to stumble as i moved the pieces away from each other. simply stuck them together and tightened the clamp. all fixed, no stumble. not my fault though! remember i am hiding the car at work, so i can't run outside and check it out whenever i want. i didn't even notice this till now. well, thanks for the help anyway, turned out to be something easy for once.

Ben87GTA

black. the way that the L98 setup on the gta is setup is like this... throttle body -> connecting baffle tubing (ribbed piece of sh*t) to plastic air baffle box which is then connected to the MAF which then leads to the air filter canister... dont know if that helps you, but it's worth a shot

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87 5.7 gta - UsBody Src Ram Air II hood, all the ghetto mods, cam, 1.6 roller rockers, chip, exhaust, functional ram air, blah blah, all that stuff. best et: 13.64 @ 104.38mph r/t .601
my baby

BAD BLACK WS6

Ok, that makes me feel better. i found the problem as stated (the tubing and box weren't even connected and bumpy dirt roads the night before busted them loose, wondered why it happened the day after being on dirt roads). but i still didn't see the MAF, but i will look for it today when i go to connect the battery. seems something is staying on and draining the battery. i found out by hearing a whirring/hiss from the rear end. i pulled fuses one by one, but it didn't stop. so i pulled the battery cable and it went away. maybe the fuel pump??? what else is back by the middle/rearend that is electric that may stay on while the car is off?? it is definetaly at the rear end. you can hear it best and loudest there. sounds like a tire going down accompanied by a whirring sound. man, if this car gave me one day of peace i would be a happy man. is the fuel pump connected to a fuse? how about the A/C motor? i believe it is not in the fusebox since i tried them all and still heard the noise.