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Right Posted by RS [Email]  (#15)  [Profile/Gallery]
(more from RS) on Mon, 2 May 2005 11:17:01
In Reply to: Re: You nailed it. But.., hondaman, Mon, 2 May 2005 07:31:05 Members do not see ads below this line. - Help Keep This Site Online - Signup |
The up-and-down idle is from an overcompensation by the ECU.
One of the things that can happen if the AIC valve is a bit sticky is that it doesn't respond as quickly as the ECU programming says it should. When the ECU is trying to power it open, it hangs and the ECU keeps trying to power it open. After some point, it snaps open too far and the ECU says, "we gotta shut you down farther" and it de-energizes the AIC. It de-energizes it for too long and the idle drops too low. This repeats until you drive off, nerves and patience shattered.
Your '91 operates just like my '89 in that respect.
One thing that I just thought of: there should be a vacuum cap on the vacuum nipple on the bottom of the throttle body. I just replaced that cap on my car after it blew off somewhere along the line. That will cause an oscillating idle.
Replace the those rubber bushings and see what happens.
There was some discussion a while ago about the charcoal canister being a contributor to idle problems in Turbos. There's a diaphragm in the canister that can be ruptured by high boost. You can check this by pulling off the hose and plugging the vacuum nipple that it attaches to.
, Sun, 1 May 2005 07:12:26, Mon, 2 May 2005 07:24:05, Mon, 2 May 2005 11:17:01 <-- Viewing This Message
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