Dangerously high idle problem

cricketo99 · Oct 25, 2006

I have an 87 and it recently has been idling super high and will not come down at all. The only way I can get it to drop it to unplug the 3 pin plug from the TPS for a few seconds and the idle goes back to somewhat normal but still high. If I plug it back in and drive within a few minutes it will be at a high idle again. Replaced and calibrated the TPS only a few months ago so I hope it is not that but I am beginning to wonder. Aparantly the IAC is good since the idle will drop down after unplugging the TPS. Any ideas? I am not getting a full 5 volts at the TPS, would this cause this? Thanks

Timber · Oct 25, 2006

Try unplugging the wiring to the cruise control servo. for a bit. That worked on mine after I dunked the engine.

BIGSLVRXJ · Oct 25, 2006

cricketo99 said:
I have an 87 and it recently has been idling super high and will not come down at all. The only way I can get it to drop it to unplug the 3 pin plug from the TPS for a few seconds and the idle goes back to somewhat normal but still high. If I plug it back in and drive within a few minutes it will be at a high idle again. Replaced and calibrated the TPS only a few months ago so I hope it is not that but I am beginning to wonder. Aparantly the IAC is good since the idle will drop down after unplugging the TPS. Any ideas? I am not getting a full 5 volts at the TPS, would this cause this? Thanks

Most of the Renix guys I have talked to (including myself) get about 4.6-4.7v input to the TPS and I sure don't have that problem. I would really suggest either a vacuum leak or a dirty or bad IAC motor. I would take the TB off (make sure you take the TPS off as well, don't get it wet) and clean the whole thing including the IAC and see if that helps. To me it sounds like possibly the IAC is sticking until the computer will give it a weird signal since you unplug the 3 pin connector on the TPS. Just my opinion but it might be worth a shot.
Hope it helps
-Collin

cricketo99 · Oct 25, 2006

Well last time I had this problem it was the TPS which was a few months ago. But it seems ridiculous that another TPS would go out that soon. There are no dead spots on the TPS. I am positive that there are no vacuum leaks and I know that the IAC functions properly because I swapped it out with a known working one and it does the same thing. Hopefully it is something electrical and won't require me buying another TPS

XJING · Oct 25, 2006

Try cleaning the TPS connector, but read this write up first.
http://www.olypen.com/craigh/idle.htm
Good Luck

davehoose · Oct 26, 2006

this happened to my 89 renix and i found that the grommet on the cable to the throttle was split and hanging up the cable so the gas was artificially accelerated. i duct taped the sucker down and that took care of that (for now). Eventually I will probably grab one from the autozoo. just a thought....
I can post pix if you need.

cricketo99 · Oct 26, 2006

Well it seems my problems are solved. Unplugged both plugs from the TPS and cleaned them (however they looked brand new). Then took out the latch relay and cleaned it just in case it were that, it was all gunked up. Unhooked the battery for a min. and voila no more high idle. It idles better now than it ever has. Thanks for the help

Dangerously high idle problem

cricketo99

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Timber

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BIGSLVRXJ

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cricketo99

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XJING

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davehoose

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cricketo99

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