1st off, you need a smiley to simulate pulling your hair out. hahah.

Ok, now on to business.
My trans is doing the famous lock-up drop at 50-70 mph. I did the TPS shielded re-wire about 8 months ago.

But now the trouble is back, and a little worse.

I went to check and adjust the TPS, but I cant seem to figure out whats what.

By that I mean I have:
3.8 V at IDLE
1.5-1.75 V WOT.

Kinda a** backwards of what it is supposed to be.

I have never removed the TPS in the few years I have had the truck. Its a 95 3500 (1 Ton) CTD with 190K.

Any ideas why the readings are opposite what they should be?
How do I fix it.

Oh, and I did the noise test, and the TPS voltage reading change smoothly from 3.8 to 1.5, thay just go the wrong way!

Looking forward to your help folks. Hate to smoke my tranny now that I drive 100 miles a day to work and back.
Thanks

Terry

 

I would think if you're getting backwards readings like that that it would never go into OD.
Can't tell you what is wrong but I do know there are times when you have to bite the bullet and replace the tps, none of the trick fixes will work.

 

I hear that.

Sad thing is, everything is reversed, but smooth.

If someone along the line had removed the tps, is it possible that it could have rotated enough to cause such a reaction?

I am a mechanic in the mining industry, and this one floors me..haha

What should the orientation of the plug be? Pointing up or down?

 

The plug should point down. The TPS is spring loaded so that it will return to idle position when you release throttle. When the TPS is removed you can put a screwdriver into the drive plate on the TPS and move it. I do this when mine is off for cleaning. I clean it with brake cleaner. It' a puzzle to me how on earth it could read backwards!

 

Hi Carl.
Ok. at least the plug is correct ;-)

My concern now tho is that if I set the idle to 1.5, then the WOT will be 0....

It is a strange situation I know. (This is usually how it goes for me..if it can be screwy, it will happen to me haha)

Is it possible that some one had removed it in the past, and over rotated the slot?
I would think tho, that if that were the case, I should experience a sudden drop from the top of high end to the low end, not a smooth transition.

 

It would almost impossible for it to read backwards unless someone disassembled the TPS and screwed it up.
My suggestion is a new TPS, any auto parts can get you one, no need for the dealer's high price.

 

I see.
Thanks for the info infidel, I will have to check around my little 'burg and see what I can find.

Makes no sense does it ;-)

 

Terry , I had a similar problem about 6 mounths ago . check out " TPS test " ticki2

Found factory splices back about 8" on the harness . They switched the colors to the plug for some reason which made everything read backwards when you followed intructions in manual . Took me 2 days to find that SOB. Good luck

 

Thanks for the info ticki2!

Days off are all gone now, but will have a go at 'er next week.
Thanks again for the tip.

Terry