Continuously Failing TPS

Hello!

So I replaced my TPS about 9 months ago with one from Autozone after seeing symptoms of failure. I started noticing the same symptoms some time last week, and chalked it up to a crappy Autozone part, so I replaced it again with the highest quality sensor that my local NAPA carried (Eichlin Ignition I believe).
Now just a few days later, I'm seeing the same symptoms again (intermittently). I'm hoping I just got unlucky with a defective sensor, but am worried it could be something else (hopefully not TCM)..

I've cleaned up all the grounds except the one next to the oil dipstick tube which from other threads I've read doesn't have anything to do with the sensor or the ECM or TCM (although feel free to correct me if I'm wrong).

I'm going to return the sensor to NAPA and get a replacement, hopefully it goes away after that.. Does anyone know what else this could be?

My symptoms are:
- Strange shifting (shifting at higher RPM than usual), and a little rough
- When accelerating at highway speeds in Overdrive, I have some serious surging or loss of power(idk what else to call it). It almost feels like it wants to downshift but won't. I would imagine that if it wasn't in OD, the RPMs would be dropping.
- Sometimes won't shift into Overdrive at all

I was recently advised by Tim_Mn that for TPS and other sensors, MOPAR is the only way to go.


See Tim's post for bad TPS symptoms.



Where was the Eichlin TPS manufactured?

Those symptoms sound about right. My engine isn't stalling but still sounds like what I'm seeing.
The sensitive to vibrations makes sense because the problems are very intermittent, but a lot of times when the symptoms appear, it is shortly after bumps or potholes (impossible to avoid in Baltimore lol).

I think the brand might actually be Delphi, I'll check the box for the manufacturer and where it is made.

I'm going to go back to NAPA and swap it out and see if that helps. If not, I guess I'll be making a trip to the dealer lol.

thanks!

Thanks for the advice. I want to say that I've read that the only adjustable TPS's are on pre 1991's..? I'm not 100% sure on that but I believe my generation being a 1996 is non-adjustable.

Quailman said:

Thanks for the advice. I want to say that I've read that the only adjustable TPS's are on pre 1991's..? I'm not 100% sure on that but I believe my generation being a 1996 is non-adjustable.

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Correct.

Did you happen to check the transmission fluid. Sometimes when you run low it can cause the same symptoms. Just idle your jeep and give the trans stick a good wipe and check to be sure. Mopar sensors are expensive I'd hate for you to get one for nothing

Sent from my SM-G950U using Tapatalk

I used to recommend NAPA's premium line of OBD sensors, but cannot do so anymore. NAPA sensors seem to me to have slipped in quality. I have never modified, adjusted, or calibrated an OBD-II TPS, they are either within specification or not.

As always, one should test and diagnose before buying parts. Installing random parts in the hope of fixing an unknown problem seldom works well.

Quailman, since it's a 96 you should be able to retrieve OBD II codes. Are any present, or do you have a MIL light that comes on? If no codes, the problem might be an intermittant fuel pump.

Do you pressure wash the engine. The TPS is poorly sealed and water incursion is VERY common and screws everything up.

Before you go any further.
Check you do not have a danm fuel pump resistor ballast...
if you do.
remove it.
splice the wires.
go and smash that POS with a hammer.

old_man I do not pressure wash the engine, as far as I can tell there's no moisture getting in there.
Tim_MN I've never really tested the sensor itself, but when I replace it, the symptoms go away instantly (just the last sensor I bought failed super quick). I returned the NAPA sensor I bought which ended up being NAPA brand (Eichlin), and swapped it for a Delphi one for a few extra bucks. No problems with it yet, and it's been about a week.
alexgalexg I feel like every time I check the trans fluid I get a different result, I feel like a dummy cause it should be simple.. sometimes the level looks fine, sometimes it comes out and looks overfilled. HOWEVER, I was on a road trip a couple weeks ago, and after about 100 miles I was pluming smoke behind me (no overheating) from fluid dripping onto the exhaust downpipe. I had assumed it was an oil leak because after all it's a jeep.. and replaced the distributor gasket because that's where it seemed to be coming from.
I did some research and found people with similar problems, where it would only happen after driving long distances, and actually turned out to be the trans fluid burping from the vent tube because it gets too hot?? The fluid collects so much gunk on its way down that it didn't look red to me but could be. If so, I get the feeling the two problems may be related.
I plan to check the vent tube for damage, and installing an aux trans fluid cooler. Even if it's not, I don't mind spending $50-100 for that upgrade.

Anyone have any ideas here?

Also let me clarify "not shifting into Overdrive," as I don't think I had a clear understanding of how the AW4 worked before..
The jeep will always shift into "4th gear" but sometimes it will not lock the RPM's (TC not locking?). I'm not a transmission guy so excuse my ignorance lol

Given a cheap Chinese clone part, the symptoms described, and the end of the symptoms with a different TPS, a faulty TPS is the most logical conclusion and this is a somewhat common problem. The TPS does not like getting wet either at water crossings or when washing the engine bay. 1996-2001 OBD-II Cherokee do not have a ballast resistor.

Tim_MN said:

Given a cheap Chinese clone part, the symptoms described, and the end of the symptoms with a different TPS, a faulty TPS is the most logical conclusion and this is a somewhat common problem. The TPS does not like getting wet either at water crossings or when washing the engine bay. 1996-2001 OBD-II Cherokee do not have a ballast resistor.

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Yeah from what I've heard, they're pretty hit or miss..
2 things I can say for sure is that:
1) I haven't seen the symptoms since I put in the Delphi sensor, and
2) When I installed this one, it seemed to have much more resistance in the "spring" than the last one that failed in a day did. The Eichlin had about 10-15 degrees less rotation to reach the mounting bolts than the Delphi one did