Cancel service engine soon light

[HotZ28]

Originally Posted by creslevi

I was hoping you would elaborate about removing the throttle body, If the TPS is bad, I see no way to remove the screws holding it on the throttle body, it's too close to the exhaust crossover and thermostat housing, to get a screwdriver on it, Thanks for all your help.Rick

As mentioned earlier, an offset screwdriver may be needed here. The last TPS I changed on a 94, I simply used a long flex shaft screwdriver. I never considered removing the throttle body, too much work for a little job like this!

BTW, don't forget to loosen the screws a little bit first and see if you can rock the TPS clockwise-counterclockwise to adjust the voltage reading!

I don’t normally recommend buying AZ parts, but if push comes to shove here, you might want to consider buying the Duralast brand TPS at AutoZone for $52.99. It comes with a 2-year warranty. If it fails within those two years, take it back for a freebie. Or, as a friend of mine does, even if it is still working fine after 1 yr 11 mo. take if off and return it for a new one!

[creslevi]

Believe me I would rather just use an offset screwdriver, I have tried everything in my toolbox and so far nothing has worked !.

I don't have a clue how I misread this earlier

Plugged in, key on, not running + lead to center (blue wire) - black lead to engine ground.
tonight on the 20v scale it say's

Idle position = 0.03
1/4 throttle = 0.07
1/2 throttle = 0.08
3/4 throttle = 0.10
WOT = 0.18

[creslevi]

If I understand correctly, The reference voltage between the gray and black wires is, it bounces between 4.8 & 5.02
The resistance from the black wire to ground is 0
Sorry to be soo dense about this, but I am not at all sure I understand what you are saying. But thanks for chiming in I need all the help I can get.
Rick

[HotZ28]

Originally Posted by creslevi

tonight on the 20v scale it say's

Idle position = 0.03
1/4 throttle = 0.07
1/2 throttle = 0.08
3/4 throttle = 0.10
WOT = 0.18

What kind of meter are you using? This reading is all together different from your previous reading even with the decimals misplaced! (Could explain a bad TPS, but I doubt it)

[creslevi]

It's a Velleman DVM 850DL new last year.
Sorry but I misread your post on 2/2 which said PCM reference and should measure 5.v, I thought that meant 5 volts, this morning with the TPS unplugged jusy measuring the voltage to the TPS it was 5.1 volts.

then I plugged it in and moved the probe to the center (blue wire)tonights readings were as follows.
Idle 0.03
1/4 0.07
1/2 0.08
3/4 0.10
WOT 0.18
So if I am reading this right the voltage is too low ?.
Rick
PS
I done it several times and it was pretty consistent

[HotZ28]

It's a Velleman DVM 850DL new last year.
Sorry but I misread your post on 2/2 which said PCM reference and should measure 5.v, I thought that meant 5 volts, this morning with the TPS unplugged jusy measuring the voltage to the TPS it was 5.1 volts.

Originally Posted by HotZ28 2/2/08 - Post #15

You can probe the terminal with a paper clip to check voltage. The TPS WHITE wire, is the PCM reference signal and should measure 5.0v with ignition on. (Engine does not need to be running) The BLUE wire will show variable voltage from a closed TB position, usually .45v, up to WOT, where it should measure between 4.0v to 4.2v max. Of course, the BLACK wire is ground.

then I plugged it in and moved the probe to the center (blue wire)tonights readings were as follows.
Idle 0.03
1/4 0.07
1/2 0.08
3/4 0.10
WOT 0.18
So if I am reading this right the voltage is too low ?.

Your reference voltage looks good! The variable readings from the blue wire are not good! If this is the correct readings, you do need a TPS. In addition, the ECM uses TPS voltage to control fuel curves, timing, and transmission shift points, to name a few. Try a new TPS, you might like it!

[creslevi]

Thanks to all that tried to help, I ended up having to take it to the shop, For the first time in my life I did not have a tool to get the throttle body off, there's a little bracket bolted to the bellhousing, that has to come off first and no universal socket I have could get on it, it was either remove the front exhaust manifold with the crossover or take it in to the shop, I took it in, of course I could not wtch them work but i could hear the air impact they used on those 2 bolts, They had to remove the throttle body to get the TPS off ( I guess there is locktite on the mounting screws of the TPS) Just think if they had used hex headed screws there none of this would have been necessary unless the screws broke off flush and you had to drill them out of the throttle body, It's a bitter lesson and cost $195.58 for labor +TB gasket, plus the TPS for $80.48 But it's done and the ECM is apparently OK, My Passing gear and Cruise control is working again, If I had it to do over I would cut the TPS off with my Dremel and replace the screws, Don't know if I would have replaced that bracket that covers the back Throttle body bolt or not, I sur don't see the need for it at first glance ??.
Thanks again.
Rick