e rock

A buddy of mine has a 95(?) 4Runner with the 3.slow that won't idle below about 1200 rpm, and usually in the 1500 - 1900 range. It's been going on for a few months now, but it wasn't really an issue except now he needs to get it smogged.

Some of the details are sketchy, but he says that it started doing this after he sprayed some carb cleaner into the throttle body to clean it out (I don't know why...). The stealership wanted to charge him $800 to replace the throttle body assembly since they thought something was sticking and they would not just clean it up. Their assumption was that the carb cleaner knocked something loose and clogged up something.

I pulled the TB off over the weekend. I cleaned, polished, blew out, etc. I'm not any kind of expert, but the whole assembly seems exceedingly simple. I cannot see how it could possibly be causing the problem unless it's a vacuum leak but the whole thing seems tight.

I removed the throttle return damper thingy with no result. I backed off the low throttle limit screw and if I manually rotated the throttle valve to the point that the butterfly was physically touching the walls of the TB, the idle would drop to about 1000 - still not the 800 it's supposed to be.

If I applied a LOT of suction to the EGR valve, the idle would drop to about 800, but it was running horribly by that point.

I can get a new TB from my parts source for about $350, but I just don't see that as the problem??

Any ideas? Maybe it's a common problem?

Thanks,
Eric

callmej75

Just wondering if you set the butterflies with the specs of the haynes manual? theres vacuum ports on the top where the butterflies are supposed to be adjusted to. When he sprayed out the throttle body was it with the TPS on? Is the TPS working properly? Just a few things that come to my mind on this situation.

94x4

Ditto to callme, he might have gummed something up as a result of the cleaner leaving residual buildup in one of the ports or damaging the ever fallible TPS.

e rock

Except for temporarily moving the butterfly stop to experiment with it, it is still in the factory position (with the paint on the screw & nut). The butterfly sits in the correct position with respect to the vacuum ports. I didn't have a manual to work from at the time, but I'm sure that's not the problem.

This TPS idea sounds more plausible, though. I know he didn't remove anything except the airbox connector when he tried to clean it. I don't know how to tell if the TPS is working correctly, but I hadn't given it any thought since the truck drives just fine and throttle response seems normal - at least according to him. Unfortunately, that's all I have to go on.

Does the TPS play a part in idle speed? Or maybe it's not in 'idle mode' because the computer is giving it too much fuel because of a faulty TPS?? I did notice that the TPS has some adjustment room and his is mounted pretty much right in the middle of the adjustment range.

My apologies for the newb questions... And thanks for all the help.

callmej75

http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml
The best writeup to date for TPS adjustment. yeh if you squirt any kinds of liquid up into the throttle body it has a high chance of getting into the electronics of the TPS. Sometimes they just wear out like any ordinary part.

e rock

Excellent. Thanks again.

callmej75

94 Yota 4Rrunner

just curious if u solved this issue as i am having somewhat the same issue, idled fine before i sprayed the TB afterwards i had a high idle, i just compensated by turning the screw in for the idle, but i threw off my cold start up, so i could use some tips too lol