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Re: SU lean/rich confusion

To: thorpe@kegs.saic.com
Subject: Re: SU lean/rich confusion
From: KeithB227@aol.com
Date: Thu, 21 Dec 1995 18:16:57 -0500
Denise wrote:

>One last try:  It's impossible to set the timing with a timing light when
>the car doesn't idle at the specified speed because the timing advances 
>with engine speed.  This means that timing set with a timing light and with 
>the idle too high will be retarded.  Retarded timing would explain both the
>high idle that can't be set down and the fluctuation.  The only way to time
>a car that doesn't run right is using static timing, but this isn't very
>accurate.  Try just twisting the distributor so that the timing is advanced
>and see if the idle can be set then.
>
>Okay, one more:  A vacuum leak generally won't cause as much problem as
>you're getting unless it's _really_ bad.  I once saw a B idle like you
>describe because one of the plugs had fallen out of the end of the intake
>manifold.  Check the two plugs and look at the manifold for cracks.  They
>have a tendency to crack at the ears where they're bolted to the head.
>Also, if the heat shield is cracked, the crack can extend under the carb
>mount and cause a big vacuum leak.  But the throttle shafts don't usually
>have that much effect.
>
Denise,

I think I have the timing advanced enough in compensation for the high idle.
 Actually, maybe a little too advanced, but it just snowed a gazilion feet
and I can't get out on a hill to see if it pings.

I'll try the timing again and look for those BIG vacuum leaks this weekend.

I just remembered, I have to be away from my car AND my computer next week
over the holidays (expecting severe withdrawal symptoms), so I'll have to get
back to everyone on what I've found after new years.

Thanks for the response
Keith (all I want for xmas is a decent idle) Baer


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