idle problem

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Jul 7, 2005 | 04:33 PM

toocool80

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Joined: Jul 2005

Posts: 63

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From: Eastern North Carolina

idle problem

can anyone tell me why my vette idles at 1100 rpms in park and then drops to 400 rpms when put in gear?

Jul 7, 2005 | 04:54 PM

Brettmc

Safety Car

Joined: Jul 2002

Posts: 3,770

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From: St Louis MO

not adjusted right...prolly a combination of timing and carb out of whack.

My brother just happened to mention last year that his 65 mustang(302, auto, holley 650 dp, comp 268) would die in drive. He said he had to feather the throttle at a stop or knock it up into neutral. I played around with his timing and adjusted his carb and that problem disappeared. Your prolly in the same situation.

Brett

Jul 7, 2005 | 06:32 PM

72CoupeORG(smc)

Racer

Joined: Feb 2003

Posts: 330

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From: Eau Claire WI

Quote:

Originally Posted by toocool80

can anyone tell me why my vette idles at 1100 rpms in park and then drops to 400 rpms when put in gear?

put in a stick, no issue

Jul 8, 2005 | 01:36 PM

iNdigo

Pro

Joined: Nov 1999

Posts: 520

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From: Front Range

Quote:

Originally Posted by 72CoupeORG(smc)

put in a stick, no issue

That's not a realistic solution to the problem. You're suggesting he spend $4500 on a new transmission and clutch assembly when really he just needs to spend 10 minutes adjusting his air/fuel/spark.

toocool... check out www.corvettefaq.com and follow basic procedures for tuning. come back here if you have questions.

cheers

the blonde weasel

Jul 8, 2005 | 02:07 PM

lars

Tech Contributor

Joined: Aug 1999

Posts: 14,375

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From: At my Bar drinking and wrenching in Lafayette Colorado

Quote:

Originally Posted by toocool80

can anyone tell me why my vette idles at 1100 rpms in park and then drops to 400 rpms when put in gear?

It's a timing problem. You have a vacuum advance control unit that is not pulling in its full vacuum range at the amount of vacuum you're getting in "drive." When you're in neutral, you're getting 16-18 degrees of vacuum advance, and when you drop it in drive you're losing timing from the change in vacuum. You can do one of 2 things:

Switch the vacuum advance from manifold vacuum to ported vacuum ("T" it into the EGR vacuum hose). This will eliminate any vacuum advance at idle and will stabilize your timing between neutral and drive. If you do this, make sure you're runing at least 16-18 degrees of initial timing.

Install a VC 1862 vacuum advance control unit and run anifold vacuum to it. This unit will hold the full vacuum advance in even at very poor manifold vacuum and will give you stable timing in "drive."