Inconsistent idle?? - Team Camaro Tech
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post #1 of 7 (permalink) Old Feb 27th, 12, 06:05 PM Thread Starter
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Dean
 
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Inconsistent idle??

Here goes. New plugs, plug wires, new dizzy, coil, points and condenser. Just installed a new Edelbrock 1406 carb and new front engine wiring harness. Car started right up and runs like a scalped ape but I noticed an inconsistent idle.

When in gear and while in park the engine seems to idle great then I can hear the engine rev up just slightly for a few seconds then return to normal. This is constant. Dwell is at 27 and timing is 10 btdc. Any thoughts?

1967 Camaro Convertible with a 327, TH350transmission, Edelbrock 1406 600cfm carb, Edelbrock 1721 fuel pump & 2701 intake.

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post #2 of 7 (permalink) Old Feb 27th, 12, 06:40 PM
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Re: inconsistent idle??

Quote:
I can hear the engine rev up just slightly for a few seconds then return to normal.
This is usually caused by too light springs in the cent....coming off at idle speed, adding a couple degrees of advance speeds up the engine, not enough fuel to maintain the higher rpms and drops back again
OR
similar
The Vaccuum advance can is not all in at idle (manifold vaccuum)...and doing the same.
Or similar again, if on ported vaccuum and the butterflies, be it secondaries or primaries open to far or primarires open too far because the secondaries are to far closed, actuvating the VA can.

There are other issues that can also cause this, like inconsistant fuel or crap in the idle cirvuits of the carb.
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post #3 of 7 (permalink) Old Feb 27th, 12, 07:30 PM
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Re: inconsistent idle??

get a holley

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post #4 of 7 (permalink) Old Feb 27th, 12, 08:08 PM Thread Starter
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Dean
 
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Re: inconsistent idle??

I'm an Edelbrock man. The last good holly I used was for a boat anchor.

1967 Camaro Convertible with a 327, TH350transmission, Edelbrock 1406 600cfm carb, Edelbrock 1721 fuel pump & 2701 intake.

"The true measure of a man is not where he stands in time of comfort and convenience but where he stands in time of challenge and controversy."
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post #5 of 7 (permalink) Old Feb 28th, 12, 12:29 PM
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Re: inconsistent idle??

Of all the carbs, my preference is holley.
Any old secondand hand carb is a boat (small boat) anchor.
over 90% of carb issues here and in real life are people trying to save a few bucks, picking up 2nd hand carbs and trying to make them work...then spending evemn more money and time to do so.....often then dumping and picking up a new carb pres set up in ball park for their application.
By this time the have figured out how the carb actually works, that they are 3 carbs in one body and how to actually dial them in.
Holley is still most proberly the easiest to tune in, work on and reliable with good performance ..As to which is the best performance depends on the the person and knowledge , tools behind the actual tuning.
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post #6 of 7 (permalink) Old Feb 28th, 12, 05:08 PM
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Re: inconsistent idle??

I always like to check the easy stuff first.

1. Check for vacuum leaks at the carb base to intake and intake to heads. Also the port to the distributor. There may be better ways nowadays but I always used a spray of carb cleaner and listened for a change in the idle.
2. If using a mechanical throttle linkage, check your motor mounts. Not uncommon for motor mounts to look good but have cracks/tears that allow the motor to move around enough to affect the throttle linkage. There are many threads on this.

If this doesn't help then deep dive and check the carb and distributor.

Russ (RJ)
The Garlic Capital, Gilroy,CA

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post #7 of 7 (permalink) Old Feb 28th, 12, 05:08 PM
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Eric
 
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Re: inconsistent idle??

Quote:
Originally Posted by 1slow64 View Post
get a holley
x2
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