Cold Idle Speed
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From: Lenoir City Tennessee
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St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15
Cold Idle Speed
I have been driving my vette quite a bit since I finally got the engine back in and am very happy. I put a 670 Holley Street Avenger carb on the car and it fires right up the first try every time. :cool: The cold idle speed was about 2000 RPM so I backed it down a notch and now it is about 17-1800 RPM. How low can I go on cold idle, and what speed should it be set at?
Also everytime I park for a few minutes it always goes back to the fast idle speed when I start it back up. What is causing this? Electric choke?
Also everytime I park for a few minutes it always goes back to the fast idle speed when I start it back up. What is causing this? Electric choke?
Le Mans Master
Joined: Aug 2000
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From: Semper ubi, sub ubi
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Re: Cold Idle Speed (Eddie 96)
I'm not sure exactly what it should be on the Holley specifically, but on old Q-jet you'd set the fast idle cam to engage when you initially pressed the pedal to the floor on startup. The fast idle cam should engage and hold the car at a higher RPM until the choke starts pulling it off. I think in a car with a bimetal spring type choke embeded in the manifold, as long as the manifold is hot the choke won't allow the fast idle cam to engage. I'm not sure exactly how it supposed to work with an electric choke.
As for your original question I think that 1300 - 1500 rpms would be plenty high enough, but according to my Chassis Service Manual, fast idle is 2400 RPM :eek: for my 69 Corvette with a 4MV Q-jet. That seems a little high to me!
As for your original question I think that 1300 - 1500 rpms would be plenty high enough, but according to my Chassis Service Manual, fast idle is 2400 RPM :eek: for my 69 Corvette with a 4MV Q-jet. That seems a little high to me!
Thread Starter
Race Director
Joined: Feb 1999
Posts: 19,659
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From: Lenoir City Tennessee
Ci 6, 8 & 10 Veteran
St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15
Re: Cold Idle Speed (Smokehouse69)
As for your original question I think that 1300 - 1500 rpms would be plenty high enough, but according to my Chassis Service Manual, fast idle is 2400 RPM :eek: for my 69 Corvette with a 4MV Q-jet. That seems a little high to me!
I think I may shoot for about 1400-1500 and see what happens. Thanks for the info.
Burning Brakes
Joined: Oct 2002
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From: Rockwood TN
Re: Cold Idle Speed (Eddie 96)
2400 sounds a little high to me. The 1400-1500 sounds much better. You could adjust it up and then back it off until it sounds right and then see what your tach says.
Le Mans Master
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From: Kingston Tenn.
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St. Jude Donor '03 & '06
Re: Cold Idle Speed (Eddie 96)
Eddie,
You can adjust it down pretty low (1000-1200 rpms).
The determining factors are:
1)How does the motor run cold? rough idle etc...
2)IF you place the car in gear from this rpm, does it quit running?
3)have you adjusted your Electric choke any?
You can adjust it down pretty low (1000-1200 rpms).
The determining factors are:
1)How does the motor run cold? rough idle etc...
2)IF you place the car in gear from this rpm, does it quit running?
3)have you adjusted your Electric choke any?
