anniesball

I'm a fairly good mechanic. I have a 94' 4Runner V6 that I need to replace the throttle position sensor.

Is there a procedure for setting this up? I have a multimeter.

runethechamp

Check out this one. Should have all you need.

http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml

cricket

Hello All,

First: Are you sure you need to replace the TPS, rather than adjust it? What are your symptoms?
Second: If you follow the adjustment procedure listed in the previous reply, there is a critical step missing (for the 3VZ-E motor). It took me a while to puzzle it out, and then I was able to confirm my guess at the following page, which is part of a whole Toy Service manual (invaluable resource: bookmark it):

http://personal.utulsa.edu/~nathan-b...93throttle.pdf

This describes in detail the adjustment procedure including the crucial missing step, which is applying vacuum to the "Throttle Opener". if you don't have a vacuum pump (I don't) you can manually disengage the opener with a wire-tie carefully positioned. Also, it is WAY EASIER to do this procedure with the throttle body off the engine. It's pretty easy to take the throttle body off, and you don't have to drain the radiator at all. (you may lose a few ounces of coolant, but that's all.) Tip: unbolt the throttle body before removing the coolant hoses, and pull it out and up a few inches; this makes it WAY easier to access the pinch-clamps for the coolant hoses, especially the one that's underneath.

I'm happy to elaborate further on my recent TPS adjustment and other related issues.

Crick

runethechamp

So I was wondering, how does applying vacuum to the hose affect the adjustment?

Marc

Me too?

69 1/2 Six PAck Bee

What if the engine does not have a "throttle opener" like on my '90 3VZE?

anniesball

The reason I asked the question is because I took my truck into the shop to have them investigate why it was seemingly gutless. The throttle itself felt stiff and wierd also.

I just recently purchased this truck, so I had no experience to go by.

My throttle body linkage on the TPS side was hitting the TPS connector when it swung around attempting full throttle. I found out that someone who worked on the truck prior installed the TPS 180 deg out. This meant that I could only get 1/2 throttle max. No wonder my truck seemed gutless.

With that said, that is why I needed the info on adjustment.

RRIND

I also have a tip to make the TPS a little easier to adjust.

I tried and tried with the alligator clips, but could'nt get them to stay or stop twisting and falling off, even with the vacuum hose trick. So when I was at the local pull your part, I got the brilliant idea to cut the pigtail and six inches + of wire off of a junker 3.0 throttle body. Now all I have to do to adjust it is, hook-up the pigtail and connect the alligator clips to the desired wires. This way I can adjust it on or off the vehicle.

Marc

that's a great idea.

cricket

Hi All,

The "throttle opener" as best I can tell keeps the throttle slightly open when the engine is NOT running. I think the idea is that for easier starting, the throttle is already cracked so you don't have to touch the pedal. As soon as the motor is running, the vacuum from the manifold "deactivates" the opener, so the throttle closes all the way. For making the TPS adjustment, the motor is not running, so the throttle is held part-way open, which would mess with your TPS adjustment, which should start with a fully-closed throttle position. Does that make sense?

If you don't have an opener, then it's not an issue for the TPS adjust. Sounds like the older motors don't have one.

Brilliant idea about using an old connector for adjustment. Wish I'd thought of that. Could probably do it on the truck that way...er no, because its really hard to get to the throttle screw and stop-plate.

Crick

runethechamp

That explanation makes sense. Thanks.

RRIND

I did'nt have a problem getting the feeler gauge in between the stop screw and stop plate. The feeler gauge set I have is 3/8" wide and is bent to 90 degrees on the end, so it fit right in.

I guess there would be a problem if I had to adjust the stop screw though, I would probably have to take the TB off to do that.

Never had to adjust any of the other stuff on the TB, just the TPS.

Elvota

I think I saw this tip on the 4crawler site...

If you do take the TB off to adjust, replace the two adjusting screws with some bolts that have a small allen head while it's out of the truck. Next time you'll have a chance of adjusting the TB while it is still in the truck with an allen wrench and not a screwdriver.

By the way, I agree that the pigtail idea is a great one. I'll have to try that.

RRIND

I replaced the TPS screws with allen heads long ago, I had a crap load of them from who knows where, so everytime I took something off of my engine that had a Phillips head screw, I'd replace it with an Allen head screw. The screw that cricket was talking about is the throttle stop screw and the stop lever, it allows the throttle plate to fully close.

runethechamp

Finally did my TPS adjustment over the weekend, and also got the confirmation of how the whole vacuum thing works. Basically, the spot where the feeler gauge is supposed to be inserted has a gap with no throttle and no vacuum. The check at 0 opening is therefore impossible to do without applying vacuum. If you don't have a pump, it actually works to attach a hose and just suck on it. It doesn't take that much to close the gap.

As far as I could see, with the 0.5 mm spacing, the vacuum just had to close a much smaller gap, and at the 0.8 mm spacing, the vacuum did nothing.

Before I did the TPS adjustment, I didn't notice any change in timing when I jumped the connectors at the check box, and I adjusted everything by ear since I couldn't get to base timing. The timing light would then show something like 20 degrees BDTC. After the TPS adjustment, I got to base timing, and it was at 8 degrees BDTC with the connectors jumped. If I disconnected the connectors, it ended up at 5 degrees BDTC.

Now I wish I would have taken pictures to make a good write-up of this.

broomjr56

My 1994 4Runner, 3.0 6 Cyclinder, won't shift into overdrive, I am leaning towards replacing the sensor. Has anyone had this problem and what was the solution.

scope103

Why does "not shift into overdrive" cause you to "lean"?

If you want to replace parts at random, that's your business. But it might make more sense to make use of the diagnostic tools built-in to your vehicle. http://personal.utulsa.edu/~nathan-b...34electron.pdf

Overdrive depends on ECT, so I would check that as well, if nothing turned up in the easier tests. http://personal.utulsa.edu/~nathan-b...98engineco.pdf