TPS problem - ZR-1 Net Registry Forums

Chuck Banks · 08-04-2023

My '92 with 101,600 miles just developed a drivability issue that I think may be related to the TPS. Upon start up with engine cool, throttle response is instant, and car has good power. When engine is fully warmed up, (easy to achieve here in AZ,) there is a hesitation on first pushing the throttle, and it seems to take a moment for the engine to develop full power. If I'm at part throttle and quickly press the pedal, there is no hesitation and car performs as it should. It has also developed a surging when off the throttle and coasting to slow down. If I keep giving it a little throttle when coasting the surge is not as noticeable. The car is not showing any codes, so I'm not sure if it would only show a 21 or 22 code if the TPS was completely inoperable.
I've owned this car for 31 years and done almost all maintenance including new Accel injectors at 92,000 and then new starter at 94,000, and Fuel pumps and sender at 100,000. I think things are just getting old and maybe thats whats causing the driveability issue.
Any thoughts on my failing TPS diagnosis. I don't have a tech 1 so would have to figure out how to set the TPS if I replace it.

Thanks, Chuck

secondchance · 08-04-2023

I would remove the TPS, rig volt meter to it and slowly move the lever observing the voltage. If the voltage moves progressively, good. If it spikes and fluctuate, bad TPS. My original TPS was worn around 1500 to 2200 rpm. Understandable?

Chuck Banks · 08-05-2023

Will test the sensor this weekend as you suggested.
Thanks

secondchance · 08-07-2023

Actually, in the abscence of reference voltage, I might have checked resistance.

Young1 · 08-09-2023

And it is an easily procured GM part. Yeah!

Chuck Banks · 08-10-2023

Tested the TPS off the car using an analog ohmmeter. The sweep of the needle was uneven from the idle position for a short distance before it became smooth for the rest of the travel of the arm. I replaced the TPS with one from Standard Motor Products. Problem seems to be resolved. Thanks for the tip on checking the TPS.

secondchance · 08-11-2023

Quote:

Originally Posted by Chuck Banks

Tested the TPS off the car using an analog ohmmeter. The sweep of the needle was uneven from the idle position for a short distance before it became smooth for the rest of the travel of the arm. I replaced the TPS with one from Standard Motor Products. Problem seems to be resolved. Thanks for the tip on checking the TPS.

Exactly the same had happened to me about 4 years ago. A new TPS and the problem was solved.

08-04-2023	#1
Chuck Banks Join Date: Nov 2018 Location: Prescott Valley, AZ Posts: 11	TPS problem My '92 with 101,600 miles just developed a drivability issue that I think may be related to the TPS. Upon start up with engine cool, throttle response is instant, and car has good power. When engine is fully warmed up, (easy to achieve here in AZ,) there is a hesitation on first pushing the throttle, and it seems to take a moment for the engine to develop full power. If I'm at part throttle and quickly press the pedal, there is no hesitation and car performs as it should. It has also developed a surging when off the throttle and coasting to slow down. If I keep giving it a little throttle when coasting the surge is not as noticeable. The car is not showing any codes, so I'm not sure if it would only show a 21 or 22 code if the TPS was completely inoperable. I've owned this car for 31 years and done almost all maintenance including new Accel injectors at 92,000 and then new starter at 94,000, and Fuel pumps and sender at 100,000. I think things are just getting old and maybe thats whats causing the driveability issue. Any thoughts on my failing TPS diagnosis. I don't have a tech 1 so would have to figure out how to set the TPS if I replace it. Thanks, Chuck

08-04-2023	#2
secondchance Join Date: Aug 2006 Location: McLean, VA Posts: 3,705	Re: TPS problem I would remove the TPS, rig volt meter to it and slowly move the lever observing the voltage. If the voltage moves progressively, good. If it spikes and fluctuate, bad TPS. My original TPS was worn around 1500 to 2200 rpm. Understandable?

08-05-2023	#3
Chuck Banks Join Date: Nov 2018 Location: Prescott Valley, AZ Posts: 11	Re: TPS problem Will test the sensor this weekend as you suggested. Thanks

08-07-2023	#4
secondchance Join Date: Aug 2006 Location: McLean, VA Posts: 3,705	Re: TPS problem Actually, in the abscence of reference voltage, I might have checked resistance.

08-09-2023	#5
Young1 Join Date: Sep 2016 Location: Ocala, FL Posts: 879	Re: TPS problem And it is an easily procured GM part. Yeah! __________________ Steve Young 1991 ZR-1 Quasar Blue Metallic/Black #729 Second Owner 1991 ZR-1 Dark Red Metallic/Black #2040 SOLD 1990 ZR-1 Dark Red Metallic/Saddle #1670 SOLD Double your happiness.....complain half as much.

08-10-2023	#6
Chuck Banks Join Date: Nov 2018 Location: Prescott Valley, AZ Posts: 11	Re: TPS problem Tested the TPS off the car using an analog ohmmeter. The sweep of the needle was uneven from the idle position for a short distance before it became smooth for the rest of the travel of the arm. I replaced the TPS with one from Standard Motor Products. Problem seems to be resolved. Thanks for the tip on checking the TPS.