1986 check engine light
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Do a minimum idle adjustment:
https://www.corvetteforum.com/forums...post1570563689
How are you pulling the codes? You should be shorting ALDL connector pins A & B with the key on, engine off, like so:
https://www.corvetteforum.com/forums...post1574918379
http://corvettephotographs.com/c4vettes/codes.htm
What they mean (make sure you look at the correct ones for your year):
https://www.corvetteforum.com/forums...post1576116036
https://www.corvetteforum.com/forums...post1570563689
How are you pulling the codes? You should be shorting ALDL connector pins A & B with the key on, engine off, like so:
https://www.corvetteforum.com/forums...post1574918379
http://corvettephotographs.com/c4vettes/codes.htm
What they mean (make sure you look at the correct ones for your year):
https://www.corvetteforum.com/forums...post1576116036
Last edited by Cliff Harris; Oct 19, 2016 at 02:31 AM. Reason: Corrected wording.
Team Owner
Joined: Jul 2004
Posts: 28,413
Likes: 3,270
From: Hartford WI
That procedure will ASSUME that everything but the setting is spot on. IF so, yes. If not, you are adjusting to compensate for an air leak or blockage in the passages, bad fuel pressure, dirty or failing injectors, etc, etc. None of which get better in time
Last edited by aklim; Oct 17, 2016 at 08:41 AM.
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
SES light on will not flash or only code is 12? Decel stalling did that start when SES stayed on? Any repairs prior? I would check no blown fuses, throttle body for carbon build up, ground wires at engine and plug wires are away from 4 wire distributor harness. Do you have FSM? there will be a chart SES light on and no codes
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
The linkage wears and bends over time. He said it runs fine, just dies when stopping. That's the classic symptom indicating the need for a minimum idle adjustment. Of course we assume that everything is OK before doing this adjustment.
Team Owner
Joined: Jul 2004
Posts: 28,413
Likes: 3,270
From: Hartford WI
Fair enough but wouldn't it be better to take apart the TB and clean it first before adjusting to compensate for any build up in the passages?
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
Not wanting to get too far off topic. Checking and minor tweaking of minimum air rate is kinda like maintenance. As engine wears and maybe TB; min air rate (min idle speed) can fall out of spec. it just happens. Disassembling TB to clean carbon then make all necessary adjustment Would be overhauling a carburetor for a low idle without trying to just turn a screw. It's not very ethical but shops and techs can more money doing it that way. If I was a consumer I would rather pay .5 (FLH)related to min/air than 2.5 flh+ parts to recondition TB for same possible out come. Oh by the way if it doesn't fix it shop/tech rarely will eat it because it's part of the diagnostic process. Cliff Harris's suggestion is the correct place to start for decel stalling.
FLH= flat rate labor hours and are the basis for what a shop or tech charges for services. For those who don't know
FLH= flat rate labor hours and are the basis for what a shop or tech charges for services. For those who don't know
Team Owner
Joined: Jul 2004
Posts: 28,413
Likes: 3,270
From: Hartford WI
Not wanting to get too far off topic. Checking and minor tweaking of minimum air rate is kinda like maintenance. As engine wears and maybe TB; min air rate (min idle speed) can fall out of spec. it just happens. Disassembling TB to clean carbon then make all necessary adjustment Would be overhauling a carburetor for a low idle without trying to just turn a screw. It's not very ethical but shops and techs can more money doing it that way. If I was a consumer I would rather pay .5 (FLH)related to min/air than 2.5 flh+ parts to recondition TB for same possible out come. Oh by the way if it doesn't fix it shop/tech rarely will eat it because it's part of the diagnostic process. Cliff Harris's suggestion is the correct place to start for decel stalling.
FLH= flat rate labor hours and are the basis for what a shop or tech charges for services. For those who don't know
FLH= flat rate labor hours and are the basis for what a shop or tech charges for services. For those who don't know
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Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
I suggest the minimum idle adjustment first to get things going in the right direction, followed by an analysis of any possible problems. Idle is the most sensitive time for problems, so that's where to do the investigation.