Hello all, I have just purchased a 1987 Grand National, and I am having problems, so far I have spent over $1000.00 and the mechanics can not find the problem. The car has a chip ( not sure which one) 48 to 50 psi injectors, TE 60 Turbo, 3" down pipe, and 2.5" Dual exhaust. The problem is that when I get on the car and then slow down the car idles real rough and feels like it wants to die. Once the car settles out it drives fine. Also after (while in the shop) if you accelerate the car will begin to have white smoke which we determined was oil and you will in fact get oil coming out of the tail pipe. We looked at the exhaust where it connects to the turbo and saw a small oil leak the was on the engine side of the exhaust. The car has 98000 hard miles. The mech said that he believes that the rings are worn and oil is leaking by. I check the oil and am not experiencing oil loss. They also said that the rough idle when I slow down is just a characteristic of the car with the large fuel injectors. I have then set at 38psi and the turbo is currently set between 10 and 12 lbs. Any info on what's going on and fuel pressure settings and boost settings would be helpful. I am told that I could set the boost between 15 and 17 lbs and it should not blow the head gasket. Thanks in advance Steven
I moved this topic so that it is easier to find and in a more relavant area.
For the bad idle, I suggest you clean the IAC and do the minimum air setting procedure (IAC reset) as outlined in the web pages. Also, you HAVE to know what chip is in it and get one that's a known commodity. Idle and streetability are greatly affected by the chip programming. You don't have to accept the decelleration stumble if the chip is programmed correctly for the injectors you are running.
As far as the oil, it sounds like your mechanic needs some training on the turbo cars. It is much more likely that you have leaking/bad seal on the turbo (on the hot side). Fairly easy to correct by sending the turbo for a "freshening" to someone like John Craig (Limit Engineering) or Harry Hruska (PTE) or any of the other turbo places.
Before turning up the boost, make sure you know that the car is mechanically sound, or you WILL blow a gasket or worse. Take some time to read all the information available to you, get a scan tool, and understand the relationship of boost vs octane vs chip timing vs air/fuel ratios.
You'll find once you get the tuning tricks figured out, these cars are a blast! Hope that helps!