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Re: Specific fluctuating idle question Posted by RS [Email]  (#15)  [Profile/Gallery]
(more from RS) on Fri, 8 Jun 2001 22:25:44
In Reply to: Specific fluctuating idle question, Wes, Fri, 8 Jun 2001 20:02:49 Members do not see ads below this line. - Help Keep This Site Online - Signup |
When the throttle is closed the TPS tells the ECU that you're in idle mode" and takes the speed feedback from the ignition amplifier to modulate the AIC valve to maintain that speed.
Vacuum leaks and sticky or worn AIC valve play merry havoc with the AIC timing programmed into the ECU firmware and keeps overcompensating. If you've cleaned the AIC valve and replaced the vacuum hoses, I'd recommend taking it one step further and replace the rubber bushings that the vacuum nipples go through in the intake manifold and valve cover. Replace the valve cover gasket, too - that can be the source of a *huge* vacuum leak.
In the worst case, the bushing that the throttle plate shaft goes through is worn enough to cause a vacuum leak. That needs a good machine shop.
On my '89, I had idle problems even after I replaced the vacuum hoses. It got better after I replaced the the valve cover gasket. The idle became rock solid after I replaced all of the vacuum bushings. The dealer over on Peachtree Industrial has the bushings for around $3.50 each but, if you are ordering other things from one of the sponsors, you can get them for $1.25 -1.50 each. The valve cover gasket is about half what the dealer is asking if you get it through one of the sponsors. That'll more than cover shipping if you want to wait.
, Fri, 8 Jun 2001 22:25:44 <-- Viewing This Message
, Sun, 10 Jun 2001 06:05:11
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