Engine/Transmission (1998.5 - 2002) RPM`S fluctuating, TPS CAUSING THIS?

[GreggNoble]

My engine used to be as smooth as a electric motor but now there are fluctuations in the rpms small but noticeable. is this a sign of the TPS worn out? my truck has nearly 300000 klms now and the Tps is origional, i also have a torque unlockin issue. thanks

 

[JLandry]

Gregg,

Assuming you're talking about a slight rpm fluctuation at idle, then it's doubtful the TPS is the culprit. At idle engine rpm is controlled by the computer on the VP44 fuel injection pump. The fact that you're also experiencing the TC lock-unlock problem might suggest electrical noise in the wiring harness. This can be caused by bad/loose electrical grounds or worn brushes and/or weak diodes in the alternator.

If you're still using the original alternator, it might be a good idea to go ahead and replace it and keep it as an emergency spare. I replaced mine at 110,000 miles, took the orignial apart, and was surpriced at how worn the brush contact areas were... very deep grooves. NEW (not rebuilt) one's can be purchased on eBay starting at $100. Let me know if you need some links.

To eliminate any grounding problems, remove, clean, and reinstall all the bettery terminals and engine/chassis grounds you can find.

Good luck,

John L.

 

[DIESELWRKS]

through the rpm range when you drive could be the Tq-conv. but I would think this would have a bucking affect on you in your seat. I would also think the cam position sensor could possible be effecting if you seeing slight irratic feelings through the rpm's.

 

[DIESELWRKS]

also Jlandry what links do you have for the alternator, I should do the same replace and rebuild the oem.

 

[GreggNoble]

WHAT THEN, ARE THE SYMPTOMS OF THE tps GETTING BAD? OR IS IT JUST A SUDDEN BREAKDOWN?

 

[DIESELWRKS]

Tps i assume your talking about throttle position sensor. On 24valves they are called apps. Do you have any codes thrown. If so what are the code numbers.

 

[KKlingbeil]

WHAT THEN, ARE THE SYMPTOMS OF THE tps GETTING BAD? OR IS IT JUST A SUDDEN BREAKDOWN?

Generally, when the APPS(TPS) starts going bad, it develops a dead spot in the throttle pedal, normally in the spot where you do most of your driving. 60mph or 73mph or whatever. Check for codes first. You can also rev it up very slowly in neutral and see if you can find a bad spot. Good luck!

 

[GreggNoble]

HOW LONG DO THE APPS lasts? my truck is an 01 and it has nearly 300000 klms on it, do they last longer than that normally?

 

[Midnite]

The APPS life is going to be different on every truck. I ended up getting a Timbo (TDR member) APPS before mine started flaking out. My stock one is now a spare, but I doubt I'll ever need it now.