I'm new to the GN's and this site. My girlfriend has a '87 GN (bought new) and it idles rough and stalls sometimes. She's had it to three mechanics and they all seem to replace the O2 sensor but it doesn't run any better. No engine codes or dummy lights appear.
Any ideas where to look?
Thanks,
John B.
Follow the procedures here to adjust the minimum idle air setting (IAC reset):
http://www.gnttype.org/techarea/maintenance/maintpage.html
Specifically:
http://www.gnttype.org/techarea/faq/IACreset.html
or
http://www.gnttype.org/techarea/faq/IACresetscan.html
Make sure the IAC pintle and housing are clean and the TPS is reset to spec. 9 times out of 10 that cures this type of problem.
Thanks Ken. Are there any instructions here on TPS resetting? I checked Helminc.com to order a manual and they are out of stock.
John B.
Ken:
I found the TPS ajustment page. I did a search for it because I couldn't find any link for it. I'll give it a try (this weekend if it ever stops raining) and let you know how things work out.
Thanks very much for your time.
John B.
I did the IAC reset and TPS adjustment. For idle I set it at 0.44 but couldn't get more than 4.18 for WOT and maintain less than 0.55 for idle. It did run better (not "as" rough) but did stall once when pulling off the interstate. It does this stalling intermittently, about once a week.
A question about Turbo-Link...does it "know" what the correct values of info received should be and automatically compare them with actual values received in the data stream? Then, based on values received, does TL recommend maintenance procedures?
Thanks much for your time,
John B.
I had to elongate the holes in the TPS to get mine in the range. My key on, engine off values are .42-4.88. Engine running .44-4.88.
TL tells you the actual operating readings (and malf codes), that's it.
Dean
There are two ways to adjust TPS up/down & back and forth 418 is not enough you need at least 450-480
Well, I got to drive the girlfriend's '87 GN last night for my first time ever in a GN. WOW.
This thing is running bad and I was still impressed. Gave it just a little throttle pulling away from a stop and the boost kicked in and chirpped the tires shifting to second. I've had some Impalas SS's and Z28's but nothing like this GN.
Now, back to the issues...
I didn't get to re-adjust the TPS because she showed up too late. But I took it for a ride just to get a feel for how it behaves. When I started it, I could smell the gas, way too much gas. At normal driving, it hesitates, chugs, and just runs rough. It didn't stall at all, though it felt like it was going to at times. I didn't feel anything funky with the trans so I'm not going to worry about the TCC solenoid for now. I printed out the Spring Cleaning article and told her that's where we needed to start. She's willing to buy a scan tool, but not for a few weeks. I believe this car has been neglected and needs a lot of work. Nothing major, just a lot of little things. I think it still has the factory spark plug wires on it.
Anyway, I've done a lot of work on cars, but don't know much about these GN's. I'm excited about learning about them and look forward to being a part of this site.
I'll keep you informed during this process and hope you don't mind me asking (many) questions.
Do all or most '87 GNs have the digital tach/boost gage with an otherwise normal analog instrument panel?
Thanks,
John B.
My 87 stock grand national will stall out after a heavy accellaration followed by a quick release of the gas pedal (not abusing but enjoying the turbo power). When I try to restart the motor it starts right up but stalls again when it comes to idle and continues to do this until the motor sits for a long period of time (more than 3-4 hours). After sitting it starts and runs fine??? Any ideas/help would be greatly appreciated!TXS
Start by cleaning the IAC