85 Idle Problem
Thread Starter
3rd Gear
Joined: Jul 2015
Posts: 3
Likes: 0
85 Idle Problem
My 85 Corvette that has an idle problem. Some time ago when the engine warms up and I'm stopped at a traffic light it would seem that the car would stall out but it never did. The idle was increased. Shortly after increasing the idle, I found a problem with the vacuum hoses leading to the Charcoal Canister so the vacuum hoses were replaced and the canister was cleaned. The car now runs alot smoother now but if I ride it locally for about one (1) hour the 'check engine' light appears. While the car is running, and the 'check engine' light is still on and its out of gear, the rpm is measuring 880. I know the ideal idle setting should be 600 to 700rpm.
Has anyone experienced this before and how did you fix it?
I welcome any and all suggestions.
Thank you.
Has anyone experienced this before and how did you fix it?
I welcome any and all suggestions.
Thank you.
Safety Car
Joined: Nov 2009
Posts: 3,970
Likes: 340
From: Adelaide South Australia
Do you know how to read the check engine light via the ALDL to find out what the fault code is ? That will be number 1 thing to do.
Here is a link to the idle / tps setting procedure,
http://www.thirdgen.org/forums/tech-...ml#post1304610
Here is a link to the idle / tps setting procedure,
http://www.thirdgen.org/forums/tech-...ml#post1304610
Team Owner
Joined: Jul 2004
Posts: 28,372
Likes: 3,259
From: Hartford WI
The idle was increased.
The car now runs alot smoother now but if I ride it locally for about one (1) hour the 'check engine' light appears.
While the car is running, and the 'check engine' light is still on and its out of gear, the rpm is measuring 880. I know the ideal idle setting should be 600 to 700rpm.
Has anyone experienced this before and how did you fix it?
I welcome any and all suggestions.
Thank you.
The car now runs alot smoother now but if I ride it locally for about one (1) hour the 'check engine' light appears.
While the car is running, and the 'check engine' light is still on and its out of gear, the rpm is measuring 880. I know the ideal idle setting should be 600 to 700rpm.
Has anyone experienced this before and how did you fix it?
I welcome any and all suggestions.
Thank you.
What codes?
How did you determine that? the idle is 880? Scantool or tach?
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
I recommend a minimum idle adjustment to start with:
https://www.corvetteforum.com/forums...post1570563689
Thread Starter
3rd Gear
Joined: Jul 2015
Posts: 3
Likes: 0
Do you know how to read the check engine light via the ALDL to find out what the fault code is ? That will be number 1 thing to do.
Here is a link to the idle / tps setting procedure,
http://www.thirdgen.org/forums/tech-...ml#post1304610
Here is a link to the idle / tps setting procedure,
http://www.thirdgen.org/forums/tech-...ml#post1304610
Thread Starter
3rd Gear
Joined: Jul 2015
Posts: 3
Likes: 0
The ECM sets the idle speed. It's programmed into the MEMCAL. It appears that you messed with the "idle" screw, which is NOT the way to do this.
I recommend a minimum idle adjustment to start with:
https://www.corvetteforum.com/forums...post1570563689
I recommend a minimum idle adjustment to start with:
https://www.corvetteforum.com/forums...post1570563689
Thank you for your response. I downnloaded the information and will read it this weekend. The job has been keeping me busy with deadlines, but with your advice it will be resolved. Thank you.
