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needing tps help

1K views 6 replies 4 participants last post by  illflem 
#1 ·
ok ive gone through 3 tps's in the last week all will range from high voltage to low voltage readings and throw a cel, ive triied adjusting them, doing the whole computer reset and still nothing all they do is throw codes and 2 of them have been brand new dodge oem tps. any help would be great.
 
#2 ·
have you checked the bell crank. My truck has about 225,000 miles on it and I can take the bell crank and make my tps jump from .700 volts to almost .900 and never crack the throttle.
 
#3 ·
Checked the linkage and all that but whats baffeling is it gernades the tps, with stock its high voltage, aftermarket is all low voltage, and with 106k I wasnt wanting this much problems from the truck
 
#4 ·
It's not RUINING the TPS units, is it? I pulled open my TPS last week, and there really isn't anything in there that can be "grenaded". It's just a couple little contacts that slide back and forth as the throttle travels. My truck jumped in and out of OD/LU the other day. I had also just installed an 800-watt power inverter. I think that the TPS circuit may've been picking up a little bit of "noise" or interference. I tried the described fix that has you solder a capacitor into the circuit (right near the PCM). It seems to be working just fine now, but I haven't had a chance to put many miles on it since.

Anyway, if you've searched the various links for TPS problems, you may've already seen it described. The line for the TPS is a low-voltage DC circuit. The wires are just standard wires that are tied into the wiring harness (no shielding). DC circuits that run at low voltage are very susceptible to picking up noise. If that is the problem, even a brand new TPS won't make any difference. The proper capacitor (around 440uF - 470uF) only costs about $.50. Just make sure you get a polarized cap and tie it in properly.

Also, you measured the voltage at both idle and WOT, right? What are the voltages you're getting at those positions? If I remember correctly, it's supposed to be around 1.2V at idle (for stock), right? From what I understand, it's closer to 5V at WOT, and anything over that will throw a code. Of course, I'm going off of memory, so I could be mistaken. Have you tried switching the PCM for a different one? Has the wiring harness been messed with at all?
 
#5 ·
wiring harness hasnt been messed with at all, and dont have a spare pcm, but its breaking the tps apart like pushing the sealed cap completey out of the tps. and like you said theres not much to gernade in there but it is pushing it out and at times it will push the contacts on the plastic. and everything is stock with wiring except for the fog lights i installed. this was the culprit when my truck lost od coming back from a trip. and with a differnt tps it actually wanted to go to the higher gears but now nada, and lost my od switch becasuse there is no definant difference now, before it would actually drive better out of od, so far 3 tps's gone, two filter and fluid changes in under 250 miles, new gov pressure solenoid, new transducer, new throttle linkage, new kick down band, mag hytec pan, plus all the fluid. i just want to be able to drive my truck and not have it be a work only vehicle that cant go over 50 mph at 21oo -2200 rpm
 
#6 ·
and its just wierd it will be a high or low voltage not just one of the two all the time. with the high voltage it actually shifted better before the tps went.
 
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