I posted this in the 1st generation forum and only got one response. Just wanted to get some more opinions before dropping the dough on a TPS. After more research I think my "cold" problem may not be a problem, just a quirk. However, the non-linear voltage decrease (while letting off the throttle) that I describe below is my concern now. Since I originally posted this I have opened the TPS up and cleaned it out but still have the jump in voltage at around 2/3 throttle let off. Sorry about the long post.

1993 D250 Automatic
I’ve been having trouble with my transmission dropping out of O.D. for about the first 5-10 minutes of driving on cold mornings. Once it warmed up it did fine. It didn’t really bother me too much because I would just let it warm up before I drove it and it is a second vehicle (my primary is a 94 CTD) so it didn’t get driven much anyway. I am about to try to sell this truck so I figure I better get it fixed because no one would want to buy it like this.
My static TPS voltage was .48. I adjusted it up to .8 and drove it about 7 miles. Everything was fine and I was feeling good about how quickly I had fixed the problem when it started doing it again. I have adjusted it in .1-volt increments between .5 and .8 and it doesn’t really seem to change the problem. If I go above .8 it won’t go into O.D. It seems to shift into O.D. fine no matter what setting between .5 and .8 however it drops out when you let off the pedal. After my last adjustment I did think to check the range from static to wide-open throttle. At WOT I was reading 3.4 vdc. As I slowly let off, the decrease in voltage was steady until about ½ to 2/3 travel and the voltage jumped to almost 5 vdc. It looks to me like the TPS is bad but I just wanted to get some opinions from you experts out there before I drop the $ for a new TPS on a truck that I just want to get rid of. And one last note, I did remove the TPS and clean it with contact cleaner to no avail. Thanks in advance for the advice.

 

I just installed a capacitor from DTT to fix my TPS problems.

http://www.dieseltrans.com/phpBB/viewtopic.php?t=405

 

I resisted replacing my tps for a couple years trying all the other fixes out there till a local trans shop hooked my truck up to a lap top and we went for drive. The tps obviously had a bad spot in it. Replacement from Napa and all is fine.

 

I have done all you have done. Put new TPS on,had tranny shop do the work$$$.Shifted fine intill next morning than back to droping in an out.I took fine sandpaper between crank and crank sen. and checked crank sen. plug.Dont know witch one fixed it OD works ! I have two 93 4x4 ***'s auto

 

Just to follow up. I replaced the TPS this weekend and man what a difference. I hate to sell the truck now.

 

WELL KEEP IT!!!! Naw, just kidding. Just out of curiosity, how much did you get the TPS for? I'm glad you got yours fixed.
Tom

 

Check this out i had the same problem in my 94 changed the tps no change it was the trans temp sensor.

 

anybody got a picture of what a TPS looks like?