Hi everyone,

I need to replace the TPS on my '87 98 and I don't know how to calibrate it. I have a multimeter, but I don't know what to measure to what value and what to adjust. Can anyone help me out?

Thanks,
Sean

Do a search for TPS on the message board here, and you will find the answers you are looking for... I would re-iterate, but the discussions already exist!

Ok, I've found that it needs to read .45 volts or so at idle. Where do I take that meaurement from? I have a meter, I just dont know where to measure. It seems to be assumed everywhere I look...

Or is it that I need a special scanner to read the voltages? That would be really lame.

Metallica!

Well, I just wrapped a piece of duct tape around the arm of the sensor, and that seems to have cleared it up. The trouble code was TPS too low, and the check engine light only came on at idle and when stopped. A bit of extra spacing was all it took to kick the idle voltage up. Not that I measured it, I just guessed. Thanks for the idea 88delta88! I doubt maladjustment was the problem though, my TPS is probably going bad (I noticed a 'dead spot' with my multimeter), and this will keep it in specs for at least emissions anyway.

Thans again guys. I'll post when the next problem crops up!

Sean


"They found me, I dont know how but they found me. RUN FOR IT MARTY!"

yea...technically the TPS isn't adjustable on these cars....but that works...

TOC Admin
Brando

Word.

JL 500/1, IDMAX 12 v.2

FYI, the connector for your TPS sensor has 3 terminals. One is ground, one is 5V, and the other is the signal line. If you measure from the ground to one side of the connector, you should get 5V steady with the ignition on. Theoretically, if you measure from ground to the other terminal you will get your TPS voltage. Idle should be about .45V, and WIDE open throttle should be about 4.5V or possibly a little higher.

If you end up replacing, buy a GOOD one. I have gone through 2 of these, because I bought cheapo replacements.

The check engine light hadn't been on since I 'fixed' the TPS. I'm sure you can all guess what it did while in line for emissions.... So I guess my little tape thing didn't work. Furthermore, the tape becomes brittle and stickless in the Illinois cold, and will probably soon fall off.
88delta, thanks for the info. That's what I've been looking for all along. I just got my reading of .37 volts, idle.
The next step now is to find a way to adjust the new TPS when installed. I cant measure the voltage and adjust at the same time since my TPS is tucked neatly on the underside of the throttle body, which must be removed to even get at the bolts for the TPS. So my idea is to find what the TPS resistance should be, so it neednt be adjusted live. I'll plug in the sensor without installing it, and adjust it until it reads .45 volts. Then I'll unplug tthe sensor without moving the arm, and then read the +5 to ground resistance. Now I simply remove my throttle body, remove the old TPS, set in the new, adjust it to the proper resistance, and put the whole thing back (replacing the gaskets of course). I'll get the new one in two days or so. I'll let you all know how it goes.


And the sultans played creole.

I never took my throttle body off to replace mine... Stubby flathead, or phillips if I remember correctly. To adjust, loosen both bolts, move to the gerneral area, and tighten one bolt. Its easy when you use the right tool. I thought it would be a bitch to replace at first aswell.

But, for all intents and purposes, you said your current voltage is .37. That is ok, is it not? The computer will bitch about anything under .2V

If you use a stubby screwdriver, you shouldnt need to remove the TB, and save those gaskets for another project!

Everywhere I read it said about .45 for idle. And since the light only comes on when its been idleing for awhile, and my voltage is only below this figure a little, it seems that .45 would be better. In any case, I decided to just get a new TPS because I measured dead spots on the one I have now. Which means that the real source of my problem is not a mis-adjusted TPS, but one whose resistance in the idle portion is abnormally high. By simply adjusting it so it idles right is only half the solution, the TPS still wont read right at some points.

Well, I did my little experiment, found it to measure like 6.47 K ohms between pins 1 and 2 to get a .44 volt reading. I couldn't find gaskets for my TB anywhere. I could find one for the TB to plenum, but there are vacuum lines on my TB too, so I had to use RTV silicone for that. Taking the throttle body off was a breeze, re-installing was no fun because I had two little coolant lines that connent to the underside that I had to put on before I applied the RTV and set it all back in place. While I was working I decided to replace my air filter too, since I haven't done that in forever. But it turns out 3 of 4 bolts were rusted on, and I had to drill them out. Which sucked. A lot. And I noticed it looks something on the upper part of the engine leaks oil pretty bad. Not sure if it's valve cover gaskets or what, but those seem likely.

So, I've reset the codes, and in an hour or so after the silicone cures enough, Ill go run it again and see what codes pop up. Wish me luck.

any luck??