76 ac idle speed
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Joined: Nov 2008
Posts: 680
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From: Denham Springs LA
76 ac idle speed
I have a stock 76 vette L48 with auto transmission. Engine was rebuilt by previous owner about 9000 miles ago. He replaced original quadrajet with a rebuilt quadrajet from a local parts hours. I set the timing according to Lars Timing Paper so I have total 36 degrees of timing around 2800rpms. Initial timing without vacuum hooked up is 12 degrees BTDC.
The car idles fine without AC on. But when I turn on the AC it pulls engine RPMs down to around 400RPM and it dies.
Car idles in park at 650 rpm, with ac off.
Car idles in drive at 600 rpm, with ac off.
I have to increase neutral idle speed to about 1600 rpm for it to continue running in gear with AC on.
Is this normal for these lower horsepower engines?
Should the A6 compressor pull the rpms down this far?
Thanks,
Roger
The car idles fine without AC on. But when I turn on the AC it pulls engine RPMs down to around 400RPM and it dies.
Car idles in park at 650 rpm, with ac off.
Car idles in drive at 600 rpm, with ac off.
I have to increase neutral idle speed to about 1600 rpm for it to continue running in gear with AC on.
Is this normal for these lower horsepower engines?
Should the A6 compressor pull the rpms down this far?
Thanks,
Roger
Tech Contributor
Joined: Aug 1999
Posts: 14,374
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From: At my Bar drinking and wrenching in Lafayette Colorado
Your carb should have an idle solenoid mounted to the driver's side of the carb. This solenoid, when operating properly, will kick the rpm up when the AC is turned on so that idle rpm remains unchanged with or without the AC on.
Lars
Lars
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Joined: Nov 2008
Posts: 680
Likes: 5
From: Denham Springs LA
Thanks Lars.
There is no solenoid on my car. It was previously owned by Bubba and had many issues to sort through.
I thought about the solenoid issue but when I looked in my AIM book it only showed a solenoid for the L82, not the L48. Doesn't really matter, if it will fix my problem.
Thanks,
Roger
There is no solenoid on my car. It was previously owned by Bubba and had many issues to sort through.
I thought about the solenoid issue but when I looked in my AIM book it only showed a solenoid for the L82, not the L48. Doesn't really matter, if it will fix my problem.
Thanks,
Roger
Drifting
Joined: May 2005
Posts: 1,629
Likes: 4
From: Somers CT
Thanks Lars.
There is no solenoid on my car. It was previously owned by Bubba and had many issues to sort through.
I thought about the solenoid issue but when I looked in my AIM book it only showed a solenoid for the L82, not the L48. Doesn't really matter, if it will fix my problem.
Thanks,
Roger
There is no solenoid on my car. It was previously owned by Bubba and had many issues to sort through.
I thought about the solenoid issue but when I looked in my AIM book it only showed a solenoid for the L82, not the L48. Doesn't really matter, if it will fix my problem.
Thanks,
Roger
