TPS faulty???

[tmarti96]

Does anyone have a foolproof method to determine if a TPS is faulty or not? I hate to buy one and then find out my problem lies elsewhere. I have a very erratic tach operation, after about 30 minutes of driving. ?Alternator quits and AC compresssor quits at the same time. I had my Bro-in-law 'mechanic' pull the transmission last week and change TC & VB Also changed injectors and exh system at same time. It has been suggested that a ground might be loose, disconnected or the like. I intend to put it on a lift tomorrow and check. Where should I look for the problem? Also, TC won't hold in lockup now. When I start out in the AM, all is fine for about 30 minutes, then the tach begins to fail, and all else at the same time. Thanks, guys.

 

[Cooker]

Have you tested your TPS voltage at idle, WOT, and then press the go pedal smoothly from idle to WOT and look for any spikes, or irregular voltage changes.



-Ryan

 

[Bigramguy]

I'd be looking for any loose grounds,wires or connectors that may have been disturbed doing all that work. It may be possible you have a wire pinched between the trans and engine too. Check all the connections at the batteries and PDC. It's got to be something related between your tach,TC lockup,alt,and AC problems,especially if they all started right around when the work was done.

 

[dslcummins]

I would look at the engine speed sensor on the crank. I have gone through this twice, the last time, was just this week. The first time, my OD, cruise, AC and something else quit and this last time, my OD, cruise and AC quit. This time, the wires on the sensor, got up against the engine and bared the wires. Check your fault codes and see what comes up.



Rodney

 

[tmarti96]

TPS faulty

Rodney,



How much space should be between speed sensor and crank pulley? I used business card, got real tight fit(barely could move card) and then tightened bolts. This was on the new sensor(engine speed) I just installed. Worked fine for abouit 30 minutes then problem came back. Now what??

 

[dslcummins]

I don't have access to my book, but I think it is . 049 to . 051. My experience with these sensors, if they were installed properly, you will never have to adjust them, they usually get damaged or maybe just quit working. There isn't really much to them.



Hope this helps



Rodney

 

[Cooker]

The correct voltage, per the service manual is 1. 0 volts +/- . 2 volts, at idle. I don't remember off the top of my head what the WOT voltage is, but I think it is 3. 5 volts above what the idle voltage was.



You can adjust the unit, even though the service manual says no. The adjustment is minimal, usually around . 2 volts. To do this you need to losen the two bolts that mount the unit and turn to adjust, and retighten the bolts, being careful you didn't lose what you just gained, or lost.



These units do go bad. It seems to me they are good for ~100k. The next problem is the units DC is selling now as replacements don't seem to last as long as the original.



-Ryan

 

[swamp rat]

Strictly for future reference

Could someone give a short list of symptoms of a bad TPS? Not that even have the slightest inkling of an idea that I have one but just curious should it ever crop up in the future, I'd sure like to have some idea of what I should look for.



Thx Swampy

 

[illflem]

Swampy, the typical symptom is hunting. This is dropping in and out of OD while cruising, sometimes it does it so rapidly that you can't feel the downshift but you can see it on your tach. You only have a TPS if you have an automatic.

 

[swamp rat]

Thank you illflem. I don't have an auto now, but in the future who knows. Consider that one logged away in the ole memory banks.