Idle problems? Acting like its carbureted
08-29-2013, 01:03 AM
#1
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Idle problems? Acting like its carbureted
I've recently acquired a 1984 928s, and while I've fixed most of the mechanical problems, one that I don't quite understand is the idle; it acts like my older carbureted cars did. When I start it, it will idle perfectly at 700rpm, but if I rev it up a bit and release, it will idle at 1500 to 1700 rpm, then if I just tap (about halfway to the floor) and release the accelerator quickly, it will drop back down to 700, and sometimes below 700, which another tap will fix. Does anybody know what could be causing this?
08-29-2013, 07:00 AM
#3
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The throttle body spring arrangement can get gritty and sticky and corrode a bit, potentially one cause.
I experienced one on an 84 USA automatic car that acted similarly, but stuck in the wide open position, too, so be careful.
I experienced one on an 84 USA automatic car that acted similarly, but stuck in the wide open position, too, so be careful.
08-29-2013, 12:18 PM
#7
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Whoops missed that. Lol.
It's likely to be a linkage problem in that the throttle body is partially sticking.
Consider pulling the center of the plenum and cleaning the inside of the throttle body and look for sticking movements with light throttle application.
It's likely to be a linkage problem in that the throttle body is partially sticking.
Consider pulling the center of the plenum and cleaning the inside of the throttle body and look for sticking movements with light throttle application.
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08-29-2013, 03:10 PM
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It is also not unusual to have broken wires on the throttle cable (pedal to engine), and surprisingly common to have the throttle pedal hanging on the carpet.
08-29-2013, 05:34 PM
#9
Electron Wrangler
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Yep - sounds like mechanical binding in the throttle cable/ linkage- watch it as someone else moves the peddle... localize where...
Alan
Alan
08-29-2013, 06:55 PM
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Wow thank you all for the help! I've only been on this forum for two days and both posts that I've posted have gotten very descriptive answers. Today I removed the air box to replace the harder to reach spark-plugs, and noticed that the throttle cable is in very very poor shape; missing insulation/rubber housing, rusted, sharp bends in it's path. I'm putting that on my short list of things to fix. Thank you all for your responses!