Engine/Transmission (1994 - 1998) TPS Problems?

[Philsram]

I know this has been posted a million times, but I still need more feedback on this subject. I own a 1995 Dodge 3/4 ton diesel 2wd automatic with approximately 124,000 miles. Lately, I have been noticing that when I drive down the highway at 60 mph the transmission will shift between 3rd and 4th gear constantly. The overdrive does not come unlocked. I have been reading the TDR about the TPS problems and I have never opened or cleaned my TPS. I didn't want to do that since that unit is sealed. I contacted a Cummings service shop and ordered a new TPS sensor. The mechanic that I talked to seemed to think that I was wasting my money, putting a bandaid on a problem, because he thought that the problem might be in the wiring. I checked the wiring, had 5 volts to my PCM and checked the signal and ground legs for shorts and found none. However, looking at my wiring diagram, I noticed that my water in fuel sensor is tied into pin 1 of the TPS. I do know that the water in fuel sensor has exposed wires. Could this cause a signal problem in my TPS that would create this problem? I have checked the fluid in the transmission, it is full but it is a little discolored. The transmission hasn't been serviced in over a year. The transmission shifts from 1st to 3rd beautifully, this condition only exists when I am at about 60mph. Any help you guys can give me would be great because I'm about ready to do the shendren fix. Thanks PW

 

[VicR]

Seems to me I read somewhere that the TPS can get a wear spot in it and not function smoothly. You can take it out and hook up a digital volt meter to it and make sure the voltage changes are nice and smooth through its whole range.



Others have removed the TPS wire from the loom and isolated it. Thats another cheap fix that can't hurt anything.



Also make sure the wires are seated correctly in the TPS connector. Thats what was wrong with mine.



Good luck.



-Vic

 

[Dave Remillard]

Go to here http://www.dieseltrans.com/dodge/index.htm click on the forum and tech tips near bottom left of page, click the custom component link and then click the link about a noise filter. May not help you fix your problem, but it explains what is happening in most cases. Also do a search and you will find plenty on this. First thing is to try spraying electrical contact cleaner on the TPS and work it back and forth, and then find the info on how to adjust voltages. I don't have that link handy but perhaps someone else can chime in with it. Good Luck

 

[shendren]

i have fixed the problem.



do a search on my name and you will find a lot. six shooter and howard durand will tell you... ...



first of all, i tried everything. dealer, new pcm. etc.



if you want to diagnose the problem you have to monitor the signal at the pcm with a volt meter in the truck with you.



you will get a good smooth signal from the tps with while the engine is off. going down the road at 60, you won't. if the tcc keeps unlocking/locking, eventually something will wear out... ... too soon unfortunately.



the problem is noise in the wiring harness. if you re-wire your tps, you will solve the problem. i have put together a tps re-wire kit. over on classifieds or pm me.



it takes about 15 minutes.



scott

 

[TFlower]

Did the Shendren fix last week. 1100 miles Sunday, Monday and Tuesday, no problems at all. Zero. Not bad for the 30 minutes it took me to install it. Did the noise filter fix first and it did nothing to fix the problem. Very happy with the kit supplied, except that it should have came with a double cup of coffee and a donut. That way the wife thinks I am working harder in the garage.

 

[Howard Durand]

shendren put together a good fix for the problem at a reasonable price.