stomper4x4

I need a few insights from anyone who's worked on their TPS. I have a 92 4runner with a 3.0.

I've been having the common hesitation/missing problem, mostly on acceleration or low to mid throttle ranges.

My first question is as follows. I disconnected the TPS and drove the truck. It was much smoother (not perfect) and had a LOT more power. So that leads me to one of two possiblities. The TPS needs to be replaced or the wiring to the TPS has a problem. SOund about right?


Second question. I was reading up on the testing procedures over at http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml and noticed that the diagram of the TPS on his page is the one that's mounted backwards compared to mine. I know some were one way, some the other way, so thats fine. But my question is, if mine is mounted 180 degrees from the one pictured, that means that the pin positions (for testing purposes) are flipped over as well right? Meaning, for instance, the Vcc will be in the Bottom position rather than on top?

Last question. Is it ok to drive it with the TPS disconnected until I make the repair? It drives so much nicer

Thanks!

thook

Correct on the first two counts. Maybe on the third. Depends on how soon you intend to repair. Try and see, eh?

thook

Sorry, I should answer that last question a bit better.

The only real concerns I could see having is engine soot, plug deposits, and potentially O2. Otherwise, it won't hurt anything. I just wouldn't go long that way.

stomper4x4

Thanks thook, I appreciate it. Glad I'm on the right track too. Once I fix this thing, if it runs similar to how it does with the TPS unplugged, I'll be thrilled!

thook

You're welcome and good luck.

Team420

One more thing to keep in mind.... Just because unplugging the tps mad it run smoother, doesn't mean the tps itself is bad, or the wiring... usually when the tps, or wiring is bad, that will throw a cel code....It could (and I bet IS) be a vacuum leak... the tps runs in conjunction with the afm and o2 sensor to set fuel mixture, so if the tps says there should b "x" amount of air coming into the tb, and the afm says there IS "y" amount of air coming into the tb, the fight each other, and make the truck run weird, also keep in mind, that in order to set the tps correctly, you must have vacuum....

thook

No vacuum is needed to set the TPS unless you're referring to vehicles equipped with a vacuum operated throttle opener. In which case, an external source of vacuum is all that's needed to operate it. Like your lungs, for example. The opener rod/piston/whatever simply has to move out of the way so the throttle plate will shut fully.

Now, even if by unplugging the TPS makes it run better, you should still run the tests to determine if it is wirinig or the sensor. The disconnecting method is only to help pinpoint.

stomper4x4

Thanks guys. Going to test the wiring and TPS this afternoon or in the morning. It's a pita getting those probes in there lol.

thook

Yes, it is. It helps if you take some small aquarium tubing (what I use) or something similar, cut short pieces that will not be so long that the probes can't reach the terminals, and push the tubing on to the terminals. Then, push the probes in. The tubing will hold the probes in place while you do whatever else you need to do.

carcrazyboy68

how do u install a new tps? i know u have to have a dvm and does it matter what direction u have to face the tps? cause my plug faces the intake manifold and on my girls 90 runner it faces 180 degrees. i have a 92