Idle speed question
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Joined: Mar 2007
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From: Texas
Car: 1987 Camaro
Engine: 5.7
Transmission: 700R4
Idle speed question
I would like my car to idle a little higher in drive. What do I do to turn it up some it is a ccc q jet.
Joined: Dec 2004
Posts: 1,132
Likes: 24
From: Midwest
Car: '82 Recaro T/A, '71 Trans Am
Engine: 305CFI/455HO
Transmission: TH700R4/M22
Axle/Gears: 3.23/3.42
Re: Idle speed question
The idle speed screw is on the driver's side of the carb. You should see a little tang on the front throttle shaft that it touches. Turn it in and the idle will go up. Spec on an auto is usually 500 RPM in drive.
Joined: May 2004
Posts: 5,338
Likes: 73
From: Lexington, SC
Car: 1987 SC/1985 TA
Engine: 350/vortec/fitech
Transmission: T56
Axle/Gears: 3.27 9-bolt
Re: Idle speed question
The idle load compensator-solenoid in the picture with plunger facing the throttle linkage-is designed to energize when the A/C is on and bump the idle speed up accordingly.
You may want to verify that it works by applying a 12 volt test lead to the connector to extend the plunger. If that works ensure the plunger extends when the A/C is on. If all works fine, the plunger may need to be adjusted to maintain the correct idle with A/C ON.
This adjustment stuff should be somewhere in the sticky above?
You may want to verify that it works by applying a 12 volt test lead to the connector to extend the plunger. If that works ensure the plunger extends when the A/C is on. If all works fine, the plunger may need to be adjusted to maintain the correct idle with A/C ON.
This adjustment stuff should be somewhere in the sticky above?
Joined: Mar 2000
Posts: 43,187
Likes: 43
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Getting all of the adjustments where they belong goes a long way toward a reasonable idle speed neutral vs. drive.
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Joined: Mar 2000
Posts: 43,187
Likes: 43
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Do you know where the other adjustments are? The E4ME sticky at the top of the forum goes through them.
What are probably affecting you are the idle mixture settings. Start with the idle mixture screws: The factory says they should be turned out 3-3/8 turns. My rebuild kit said 4, that's where both of mine are set right now and they are working fine. Set those somewhere in that neighborhood, then go to the next step.
The mixture control solenoid (MCS) duty cycle should be in the 50% range in closed loop, which is 30 degrees on a dwell meter set on the 6 cyl scale. What equipment do you have access to? If a dwell meter, attach the positive lead to that green connector that doesn't connect to anything over by the AC housing, and the negative lead to a good ground. If you have scan equipment available (I have an Auto X-ray), hook that up and look for the MCS duty cycle. Make small (1/8 turn at a time) adjustments to the IAB and watch the response. Get that 30 degree (50% duty cycle) while at 500 RPMs idle.
(If you don't have a dwell meter, consider http://www.harborfreight.com/cpi/cta...emnumber=95670 )
This assumes your rich and lean stops and float height are properly adjusted. Those are static adjustments made when the carb is assembled.
Finally, where's the TPS? It should be at .48 +/- .1 volts at idle.
If these things aren't right, you won't get the idle speed in neutral vs. in gear to behave.
What are probably affecting you are the idle mixture settings. Start with the idle mixture screws: The factory says they should be turned out 3-3/8 turns. My rebuild kit said 4, that's where both of mine are set right now and they are working fine. Set those somewhere in that neighborhood, then go to the next step.
The mixture control solenoid (MCS) duty cycle should be in the 50% range in closed loop, which is 30 degrees on a dwell meter set on the 6 cyl scale. What equipment do you have access to? If a dwell meter, attach the positive lead to that green connector that doesn't connect to anything over by the AC housing, and the negative lead to a good ground. If you have scan equipment available (I have an Auto X-ray), hook that up and look for the MCS duty cycle. Make small (1/8 turn at a time) adjustments to the IAB and watch the response. Get that 30 degree (50% duty cycle) while at 500 RPMs idle.
(If you don't have a dwell meter, consider http://www.harborfreight.com/cpi/cta...emnumber=95670 )
This assumes your rich and lean stops and float height are properly adjusted. Those are static adjustments made when the carb is assembled.
Finally, where's the TPS? It should be at .48 +/- .1 volts at idle.
If these things aren't right, you won't get the idle speed in neutral vs. in gear to behave.
Joined: Mar 2000
Posts: 43,187
Likes: 43
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Forgot to mention: Set the timing before starting any of this.
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