1979-1993 & 94 Conv [Subscribe to Daily Digest] |
tps's are pretty simple. there are two types on the c900: potentiometer, and switch. i think you said you had lh2.4 which i believe is the switch. this means that when the throttle is closed, you are at one setting. as soon as the throttle is moved to open, you are on the 2nd setting (closed loop on the ecu). when you get to 75-80% open or so, you are on the third setting (open loop for wot). you can hear distinct clicks when you hear these set points. you want to make sure then when the throttle is closed, the tps is in the 1st setting and not the 2nd; which can occur if the screws come loose, or the switch gets bumped, or someone moves it. to further complicate things, if you adjust the idle screw, you need to make sure the tps is aligned correctly to operate as above. as i said before, i would not rush to mess with the tps. either it is bad, or it's something else. you start messing with the idle screw and the tps alignment and you will be chasing your tail. i've done it before and it was a pita to get back right again.
as far as why jumpering the two leads made it idle correctl...my guess would be that you sent the ecu to closed loop and the amm and o2 sensor worked to maintain the correct a/f mixture. when you attached the plug again, the ecu thought you were back at idle (throttle closed) and your other problem was visible again. i think it points again towards a vacuum leak, but keep running around with other things until you are stuck. and then decide that ensuring a tight intake is worth the effort. i understand your feelings. i chased an idle issue around for a couple months once. everyone kept telling me to make sure the intake was tight and i wanted the easiest fix that didn't involve a lot of work. it turned out i had 3 vacuum leaks that were causing issues and once they were fixed, all was well.
btw, it might help to run a little boost and listen for a hiss. this will help finding leaks. anyway, good luck.
posted by 209.6.246...
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