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What year/model? Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Wed, 18 Sep 2002 22:50:48
In Reply to: rpm's dropping, tyler, Wed, 18 Sep 2002 21:38:11 Members do not see ads below this line. - Help Keep This Site Online - Signup |
My first guess is a bad/misadjusted throttle dashpot, followed by a bad hooter valve, if you have a turbo. On the years equipped with one (most), the dashpot is a flying-saucer-shaped disk with a plunger coming out, right under the throttle arm on the throttle body. When you release the throttle, the dashpot plunger catches the throttle arm, and eases it down to idle. It should take about 3 seconds for the throttle arm to move the last few millimeters. If the dashpot is misadjusted, or the damper in the dashpot is dead, the throttle just snaps shut. This sudden throttle closing is too fast for the AIC to handle, and the engine speed droops.
The other possibility is a bad hooter (AKA Turbo Bypass) valve. When boosting, if you quickly close the throttle, the turbo is still spinning and trying to push air against a closed throttle plate. The hooter valve ports this air back to the input of the turbo. This keeps the turbo spinning and prevents high pressures at the throttle plate. A stalled turbo interrupts the exhaust flow, and can cause problems like you see.
It always helps to mention the year and model of the car, as different years/engines have different things that can go wrong.
posted by 12.79.33...
, Wed, 18 Sep 2002 22:50:48 <-- Viewing This Message
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