Going through TPS regularly

[sntrym]

Vehicle: 95 Yukon with TBI Vortec 350. Has Be Cool 2 row radiator, trans cooler, and electric fan. Tuned with the help of Dave at Gearhead EFI. Runs awesome and normal temp (195F)

Problem: In the heat, I keep having to replace the TPS. Standard, Delco, doesn't matter. They all work fine for a while then die in the heat. It seems every summer I have to swap it out at least once. I suspect it's because I have an electric fan and there is not always air moving under the hood. There are shorty headers on the motor too which also add heat under the hood.

Question: Is anyone else running a similar setup and have you run into this issue of the TPS not liking the underhood heat? TIA

 

[kenh]

LOL.... Mine eats ICM's for breakfast..... Sorry, no help.

Ken

 

[Schurkey]

Vehicle: 95 Yukon with TBI Vortec 350.

What is a "TBI Vortec"?

Has Be Cool 2 row radiator, trans cooler, and electric fan. Tuned with the help of Dave at Gearhead EFI. Runs awesome and normal temp (195F)

Problem: In the heat, I keep having to replace the TPS. Standard, Delco, doesn't matter. They all work fine for a while then die in the heat. It seems every summer I have to swap it out at least once. I suspect it's because I have an electric fan and there is not always air moving under the hood. There are shorty headers on the motor too which also add heat under the hood.

Question: Is anyone else running a similar setup and have you run into this issue of the TPS not liking the underhood heat? TIA

How do you know that the TPS are failing because of heat, instead of some other cause?

 

[sntrym]

What is a "TBI Vortec"?

A throttle body injected Vortec engine. Just like you would say a carbed Vortec. It doesn't matter much, just some info.

How do you know that the TPS are failing because of heat, instead of some other cause?

If you read the question I'm looking for similar setups and if anyone has had the same experience. The TPS voltage drops to 0 while driving and the engine light comes on. I unplug it, plug ti back in, it works for a minute then does it again. I replace it, the new one works fine. Bench test the old one and there is a hole in the output voltage when turning it. I'd say it's bad.

 

[Schurkey]

I don't question that they've gone defective.

I question that they've gone defective BECAUSE OF HEAT. Sure, it's possible, but I wouldn't expect electric fans not turned on to be a root cause.

I'm wondering if the throttle shaft is bent, causing stress on the TPS as the shaft turns--or some other issue yet unfound.

 

[sntrym]

Killed another TPS a couple weeks ago near Nashville. Rainy night, voltage shot up to 4.5v on the highway. Had to wait for the parts stores to open in the morning, got a Durashit from Autozone and a Delco from Advance. Installed the Durashit since Advance wasn't open yet and kept the Delco as a spare. 4500 miles and two weeks later, the Durashit died. Installed the Delco and it's good, for now.

I have a tablet mounted on the dash and watched the idle voltage on the dead TPS rise from 0.8 to 1.0 to 1.1 to 1.2 etc. all the way to 2.0 before I was able to get home.

I'm still not sure why they keep dying but I definitely am keeping a spare with me and a T25 to swap it out.

 

[PlayingWithTBI]

I'm still not sure why they keep dying but I definitely am keeping a spare with me and a T25 to swap it out.

This is one time I might question the condition of your PCM and it's 5VDC rectifier/output? Normally the PCM is robust and rarely fails. Is your MAP sensor working OK, it s/b fed by the same power output?

 

[Schurkey]

Did you ever check the throttle shaft for being bent, or riding on worn-out throttle body bushings?

 

[sntrym]

This is one time I might question the condition of your PCM and it's 5VDC rectifier/output? Normally the PCM is robust and rarely fails. Is your MAP sensor working OK, it s/b fed by the same power output?

As best I can tell everything else is working fine and voltages are normal when tested with a multimeter.

 

[sntrym]

Did you ever check the throttle shaft for being bent, or riding on worn-out throttle body bushings?

I went back and did a quick check and it does not appear to be bent. If I pull up on the linkage plate there is a very very small amount of play but nothing I would consider abnormal. The throttle plates move as they should in the bores with no hitting of the sidewalls.