Hey, New 1990 TGP owner, Red/Tan, Having Problems.

[SantaCruzTGP]

I'm new so bear with me. I've scoured the discussion threads but geeze, there is alot to look over w/ dial up connection. I'm so stoked to have come across a deal I couldn't refuse. I have owned my 1990 TGP for 3 days now and am in desperate need of help.

I have an appointment to bring the car into Pontiac next week, They are going to diagnose the problems, at which point I will try and fix myself.

 

So, the guy I bought it from just replaced the IAC and I have the receipt for it, he also put in a new O2 sensor. This happened last week. The car is still idling erratically all over the place, then once I get my foot into the accelerator the car looses power then lurches forward, looses power, then the turbo kicks in and takes off like mad and doesn't want to shift into third, instead it just climbs toward redline. If I let the car just idle while rolling it jerks back and fourth. The smoother I try to drive it the more it wants to lurch.

In cleaning the car last night I found a vacuum line under the passenger seat. It has the rubber piece that attaches to the turbo body, but the smaller connecting hose looks to have been melted and severed right where it should connect above the valve cover. If I get one of those hoses again, could that be the solution? Yes there are 3 outlets above the valve cover, the top left one is open and nothing is attached, the other two are connected but to other locations. I think maybe they are wrong. I'll go home today at lunch and see.

I also read that this could be a possible issue with the xover pipe being cracked? I inspected what I thought to be the crossover pipe and found no cracks to speak of.

I'm going to read up on the transmission issue. I think I want to replace it with a new one. The car clunks when it tries to shift into first under braking, and the shifting issue from second. Also when putting it into gear with the high idle is excruciatingly painful. Heck, maybe it's just a computer issue.

Shit, then the darn thing needs to pass smog!

But, boy does this car take off!!! I have a Honda VTR1000 and it could rival the take off velocity.

So Monday, I'm taking her to the Pontiac Dealer to diagnose the problems for 95 bucks. I don't know if they will know what they are dealing with so I'm going to request their best technician.

BTW, I'm 29, this is my first GM car! I'm so stoked to own American and have this be my project car / everyday driver. I will get involved with the discussion board.

-Jeromy

[Guest Anonymous]

I would say your x-over is your problem.

 

The vacuum lines you're talking about sound right. One port should be open with nothing attached.

[skalor]

I would have to blame the x-over for the eratic idle and if it's original then it leaks. The stock x-over has a heat shield over it so you can't see the cracks without taking it off and taking the heat shield off. On my second TGP you could easily hear the x-over leaking while it was running.

 

The tranny problem could be the vacuum modulator is bad as that would cause hard shifts and it would really clunck when you stop/start out. To check this pull the vacuum line off of the modulator and see if there's tranny fluid in it...if there is then it's bad. Also, there will be a checkvalve in the vacuum line that runs to the modulator(right in front of it). One of the ports is supposed to be open so leave it open, and if it's capped, uncap it.

 

Here a picture of the what the boost control vacuum lines should be like(don't make fun of the dirty engine bay as the car was only $990 and that was the day I got it. ) http://fp.enter.net/~nicolette/images/turboGP/boostsolenoid.jpg

[SantaCruzTGP]

So, I got home and looked at the Vacuum hose connections coming from the turbo, It is supposed to attach above the Cylinder head, but instead, what I found was...

It was connected to another vacuum T line fitting just below the turbo and too the left. I connected them together and boom, I started the engine, the idle problem subsided but a ton of smoke started to appear in the location of the xover pipe, and it was sputtering pretty bad on the quick test drive is just did. Also, alot of smoke from the tail pipes too. So, it looks to be the Crossover pipe! Thanks everybody for your input. Now it's time to replace it.

I'll be coming back for advise shortly, you can bet on that!

-Jeromy