morrisonclunker

I replaced the head on my 86 4runner and finally got the thing started. Had the idle at 750, but had it timed at about 12 degrees instead of 5 because it was working the best at the time. I also had problems with maintaining an idle when it was cold. So I continued poking around to see if I could get running any better. A friend of mine let me barrow his Toyota shop manual for a 87 4runner and it had resistance checks in it for the throttle position sensor. I am limited in my electrical ability but nothing seemed to be adding up as I did my checks. So I took the sensor off and begain turning it to see its range of motion. I would turn all the way clockwise let go the spring would return it about a 1/4 of the way back. So than I renstalled it advancing it just a little and seemed to help a lot. I was able to turn my idle screw in a little more and got it timed to 5 degrees. I thought I fixed my problem until I turned the throttle. When I turned the throttle the engined reved as it should but then died down and continued the surging cycle. So then I tried returning it back to its original spot and still continued to do the same thing. Any ideas on this one? I dont think I installed it wrong although I am capible of anything. Does anyone think I have a throttle position senor I would think it would have spring tension throuout its whole range of motion. Any help is appreciated. Thanks.

TORTIS

iTrader: (1)

Are your vacuum lines in good shape? So did the tps ohm out fine in all the test?

854x4

The tps sensor should have spring tension through the whole range of motion. The throttle pushes the tps foward but does not pull it back spring tension does that. If you have the tps off the truck you should be able to turn the tps and let it go, it should snap back untill it stops it should not hang up. I have a similer problem on my 86 the tps would stop 1/4 inch before it was supposed to. I didnt figure this out untill I got a code. Mine would idle bad when cold and sometimes surge at about 30 mph.

morrisonclunker

That is what I thought and think that is my problem. The only thing is that it worked not well but it worked before I messed with it. This one only moves a 1/4 of an inch. How much was the tps?

morrisonclunker

The ohm test did not seem to be working at all. The procedure had you place feeler gauges of i think .57mm under the throttle set screw and check the 2 bottom pins and you were supposed to get continuity. I didnt get anything.

854x4

Did you get any codes? Remember to clear any codes you might have gotten when messing with the tps. Another way to tell if the tps is bad is if you jump the timing connector and the timing doesnt change, but this way does not always point to the tps, it just helps narrow it down. I got a used tps off ebay for about $8 dollars shipped. What is the part number on the one you have?

854x4

I forgot to add, remember to trust your diagnostic skills. If your not sure or have questions this is the place to ask.Also I know for a fact my tps is bad but I have yet to confirm it because the engine blew a head gasket and I'm now rebuilding it. Check out my thread if you want to see the process.