My dad has an 87 GN with a little over 90,000 miles that he bought recently. One of the local Buick tuners replaced the plugs and wires for him, and the coil pack and module (supposedly "good" used) a few months ago (this car is rarely driven), but that had no effect on the problem. When the car is first started, it will idle for a little while, but if you try to put it in gear it usually dies. The engine isn't very responsive off idle either. Once it has warmed up though, it drives normally. My first thought was the TPS voltage, which I adjusted (it was reading .30 at idle, now is at .40; at WOT its just over 4.0). This seemed to help, but the problem is still there. Any ideas? I'm pretty good with F-bodies, but don't have a lot of experience with stuff like this on turbo Buicks. Thanks!
87 GN Idle Problems
- Thread starter Joe Hinds
- Start date
salvageV6
Daily Driver
- Joined
- May 25, 2001
I'd start by seeing what chip is in there then follow the warmup temp.s on a scantool to see if it's the temp. sensor the ECM uses.
Also need to verify proper IACV operation and to see it's set right with the TPS values as they are adjusted together and interact.
Need scantool values at idle.
Also need to verify proper IACV operation and to see it's set right with the TPS values as they are adjusted together and interact.
Need scantool values at idle.
You may want to remove the IAC valve for a 'gentle', but thorough cleaning. Also, pay attention to the condition of the throttle body. For instance, the orifice in the TB where the IAC resides is the seat that the IAC valve closes against, and it can accumulate a lot of carbon, dirt, and debris. The easy way to do this is with carburetor cleaner and a small stiff brush. Go to
this site
Click on 'Basics/tuning', then click IAC adjustment.
HTH
this site
Click on 'Basics/tuning', then click IAC adjustment.
HTH
