Abrupt Stops - Kills it.. TPS Problem?

[TimRTGP77]

Hi,

I really like my TGP but right now there are 2 annoyances that bug me..

 

1) 30 per cent of the time if i come to an abrupt stop.. say a stop sign/light especially after I have been driving it sort of hard.. the car surges and kills .. all the dash lights come on and I have to restart it.. which could be dangerous if not at a stop sign/light.. is this a TPS problem? other cause?

 

2) The transmission seems to do a lot of searching.. and then when it downshifts/upshifts I feel a noticeable thunk when it finds the gear.. been told this is normal but this is the only car that I've driven that does this.. it's a noticeable.. solid feeling catch usually happens on an on ramp where i've slowed up and then have to accelerate again..can this be fixed or is it a characteristic of this transmission? (4 speed auto/w od)

 

 

Thanks... Tim

[Garrett Powered]

the stock chip always does that. dies at stoplights. could be also from vac leaks and exhaust leaks.

 

try and get a top gun chip or custom tune.

 

 

you probably should start with a motor and tranny mount and some new dogbones. see if that firms it up and go from there. check subframe mounts, struts, trans modulator, and tv cable after that.

 

 

dog bones are the easiest, you can find them at the junk yards all day. good luck!

[grandprixnyc]

My car is a 3.4, so this may be totally different... but... I had the stalling at an abrupt stop problem. I never really figured it out but after I put a new battery in the problem seemed to stop. The alternators on these (loaded) cars are a little undersized (if your on the original) and an abrupt stop might be cutting the juice a little too much on these antiques.

[mfewtrail]

My car is a 3.4, so this may be totally different... but... I had the stalling at an abrupt stop problem. I never really figured it out but after I put a new battery in the problem seemed to stop. The alternators on these (loaded) cars are a little undersized (if your on the original) and an abrupt stop might be cutting the juice a little too much on these antiques.

 

That's definitely a possibility, especially with the PMIII brake setup.

 

There are also a number of other things that could cause that problem. I would start by cleaning the throttle body and IAC(idle air control) valve and see if that helps any. When the IAC gets gummed up, it will not move as freely as it should and can cause stalling.

[Garrett Powered]

one of my cars has a stalling problem and only stalls with the stock chip. also, Jims car does the same thing and he has a stock chip. they both have stock alts too, but mine cleared up right away when I stuck in the tg160 chip. the red car never did really stall that much which is weird because the with the other one and jims car, I cleaned out the tb and iac motor and it didnt matter. I guess it is a common problem for tgp's and Jeff supposedly made changes in the chip to fix it.

[TimRTGP77]

Garrett Powered, where do I get that chip, how much does it cost? and was it specifically programmed to fix the killing problem? What other things were adjusted in the chip?

 

-Tim

[killinprixs]

you using delco plugs? new wires? clean throttle body, clean iac, get an aftermarket boost gauge so you can see how much vaccum your running, the stock guague is 100% bogus, um ...should have anywhere from -18 to -21 at idle. An exhuast leak will make the car stall as well. See or hear any exhuast under the hood? Did you check the ecm for codes with paper clip method? All of this is very vital to a properly running TGP. theres no point in getting a chip if you havnt done any of this first. Hard to diagnose without knowing whats original on the car.

[Garrett Powered]

http://www.w-body.com/forum/index.php?topic=71022.msg919398#msg919398

 

 

I would offer him a couple hundred for it since he is selling it for a grand. try and buy the crossover too.

 

the chips used to sell for $375 and the pipes were $425 so you could justify buying the whole car for just those two parts.

 

and yes, many changes were made to the chip to improve driveability. also more boost and power.

[killinprixs]

so your telling him to completely ignore properly diagnosing the problem and just throw a chip at it? Yes replacing the chip has fixed a few stalling issues, but it only masks the real culprit in my opinion. I wouldnt underestimate ASC mclarens tuning capabilities and if it really was a problem, was there a recall?

[krenzy]

Is it possible that the MEMCal itself just needs to be replaced with a different MEMCal? Have you replaced the ECM yet? I'm willing to bet your problem is within that area. Sounds familiar with what my first TGP was doing.

[GP1138]

so your telling him to completely ignore properly diagnosing the problem and just throw a chip at it?

 

I was wondering when someone was going to call this. No, don't buy anything right now, try truly diagnosing the problem. At this point, we don't know much about the car. What's been replaced? It could be coils, it could be a bad fuel filter, it could be plugs/wires, it could be a hell of a lot of things. I'd start with a bad IAC, does it hunt at idle, idle badly or jump at all? Second, starting off, does it have plenty of power? Doesn't chug or shudder?

 

Garrett Powered, I don't know how you can 100% undoubtedly say that this guy's problem is the ECM chip, unless you've seen his car and know that it's 100% exactly like your car that was fixed with the chip. I don't see why you're trying to get him to buy ~$300 chip to fix his problem, which could be anything at this point. I'm glad you're not working on my car.

 

[Garrett Powered]

thats what I would do if I had a stock x-over and chip.

 

I might buy that car for a thousand, take the chip and pipe then put on my old one and sell the car for more than I bought it for.

 

He can do whatever he wants, I am not working on his car even, or yours. just telling him what the chip did for my car. it could be many other problems I agree. In fact I did not say it was set in stone that a chip would solve the stalling problem even though the stock chip sucks like that. you should get a tgp and see for yourself.

[mfewtrail]

so your telling him to completely ignore properly diagnosing the problem and just throw a chip at it? Yes replacing the chip has fixed a few stalling issues, but it only masks the real culprit in my opinion. I wouldnt underestimate ASC mclarens tuning capabilities and if it really was a problem, was there a recall?

 

Some of the early chips were more prone to stalling, but that doesn't necessarily mean that the chip is what is causing the issue on the original poster's vehicle. There are a few different "stock" chips out there as some updated ones were released to correct issues. I believe the AZRC version is the best out of the stock chips.

[Garrett Powered]

I rest my case. I dont work on anything but turbos AND since only the few of us who bought these cars new back in 1989/ 1990 (not me, I got my first in 2000) know when different versions of these chips were released. not that it matters because better stuff is out now, but like I said my red car which was made in 1989 never stalled once on me and the black car I had stall all the time was built in april 1990. literally ALL I had to do was switch the chip to the top gun and no more stall, period.

 

Soooo... If you dont have the latest update, there is no reason not to get it.

 

 

[TimRTGP77]

Hi,

Car is mostly stock.. one coil pack replaced, along with 2 alternators, battery.. needs crossover and maybe a chip. Has 95k on it. Idles fine usually. I don't know I am not mechanic.. I ask questions here and hopefully get good responses. Why not go with replacing the chip first? instead of last? I really like the car but it dying at inopportune times sucks not to mention that it could be dangerous. I'd buy that car on the east coast if I lived on the east coast.. I am in the midwest.. that car sounds like it's a good candidate to be fixed up not canabilized for parts. Where do I find a top gun chip and an aftermarket cross over pipe? Has anyone ever had an engine fire with these cars?

 

-Tim

[Garrett Powered]

you find that chip and that pipe used. period.

 

I would replace your battery cables, there, a cheap possible solution for you. sand off the paint where the ground goes to the core support. clean things up some on the block and chassis ground. very common problem area for me at least.

[TimRTGP77]

Hi,

Could a slightly leaky crossover pipe be causing this? At an abrupt stop it almost feels like it wants to hop forward and then kills.. if I feather the brake and pump it instead of jamming it on.. it is more like to continue running. The only leak I have is the crossover is not too sound.

 

Tim

[Garrett Powered]

wait, what did you just say?

 

wondering if its the crossover, probably is, does it smell like exhaust under the hood or through the vents?

 

are you going to replace any of the battery cables or at least clean up the grounds and try to get 13.5 volts or so?

 

thats what I would shoot for to start with.

 

want me to make a list of to-do stuff for you?

[killinprixs]

haha yea he says he hears the crossover leaking.

[TimRTGP77]

It smells fine. I was wondering if it could possibly be the co.. why does that make it so? Sure, it would probably be helpful to have a list. Thanks.

 

Tim

[Garrett Powered]

first, get new battery cables and get the grounds all cleaned up. new batt side post bolts and everything. make sure the paint is all removed and use the copper colored antiseize grease on the threads. there is a ground from the block-to-battery and another for block-to-chassis. the block-to-battery includes a smaller gauge battery-to-core support, this is where the paint can be scraped. just slop on the copper antiseize over the bare metal and it will never rust.

 

If you are still not getting a good charge we can discuss new fusible links and charge wire upgrades.

 

order some new mounts for the motor. "hydraulic" motor mount and tranny mount and dogbones. this will be a dramatic improvement for the slop you are experiencing. It may clear it up all together!

 

again there more things we can try if this is not enough, but for sure is the first step in the process of elimination depending on what maintenance has been done recently.

 

look every few days in the classified section for tgp parts for used top gun chips and crossovers.