tps nightmare

[MonteC]

this problem has haunted me since ive bought the car. 90, 3.1, 4t60

 

i get a recurring tps code 22, the car runs fine, but when you sit at a stop light or just whenever the car sits for a few seconds the revs will surge between 1500 and 500, and if you sit longer than 30 seconds while its doing this, the car will shut off, but it will start right back up and drive fine until the next stoplight.

 

CODE 22

 

Trouble Code 22 indicates that the Throttle Position Sensor (TPS) is reading abnormally low. TPS volts should be close to 0.42 V at closed throttle and rise smoothly in about 0.02 volt increments to a maximum reading of about 4.85 volts at WOT.

 

Code 22 will set if:

 

* Engine Running

* TPS reading < 0.25 volts for 3 seconds

 

Typical causes for this code include:

 

1. Circuit Open or Shorted to Ground

2. Faulty Connection

3. Faulty TPS

4. Defective ECM

 

TPS cannot be adjusted, the TPS has an auto zeroing feature.

 

 

well, i replaced the tps with a brand new one, still a code. i scored a throttle body with a working tps on it for cheap, swapped it on, and still got a code.

 

BUT, my girlfriends dad (seasoned mechanic) and i (novice mechanic) were checkig the voltage on each of the three wires, the ground and the input were checking out good, but the output was reading zero.... this was directly out of the connector, like the connector had a short in it or something.

 

what do you guys think? i dont wanna go hacking up my wiring harness until i get some feed back.

 

 

*edit* and yes ive done MANY idle relearns and nothing has changed.

[Robby1870]

Well....if the output is 0V then something with the connector is wrong. So you're saying you unplugged the connector and ran the engine and measured the voltage right off the posts on the TPS? You might try finding out which pin on the ECM gets the output of the TPS and running a new wire directly from the TPS output post to the ECM.

 

Just trying to get a feel for how exactly you tested it

[MonteC]

Well....if the output is 0V then something with the connector is wrong. So you're saying you unplugged the connector and ran the engine and measured the voltage right off the posts on the TPS? You might try finding out which pin on the ECM gets the output of the TPS and running a new wire directly from the TPS output post to the ECM.

 

Just trying to get a feel for how exactly you tested it

 

no, we tested it with the connector on. he kinda pinched the tester probe into the wire where it would get a reading, not too much that it would leave a hole, but enough to where it got past the insulation. not the best way or the most accurate way, but it did get us some readings.

 

im gonna try testing it right off the post tonight and seeing what that nets.

[Robby1870]

Well....if the output is 0V then something with the connector is wrong. So you're saying you unplugged the connector and ran the engine and measured the voltage right off the posts on the TPS? You might try finding out which pin on the ECM gets the output of the TPS and running a new wire directly from the TPS output post to the ECM.

 

Just trying to get a feel for how exactly you tested it

 

no, we tested it with the connector on. he kinda pinched the tester probe into the wire where it would get a reading, not too much that it would leave a hole, but enough to where it got past the insulation. not the best way or the most accurate way, but it did get us some readings.

 

im gonna try testing it right off the post tonight and seeing what that nets.

 

Yeah, I'd say try that and see what that gives ya. Make sure the potentiometer is working correctly. But, this is your like 3rd TPS and I cant see you getting 3 bad ones in a row. Im thinking either the connector is not connecting, you've got a small break in the output wire somewhere or a bad connection at the ECM.

[MonteC]

also im on my second ecm. (different reason)

[Jcrow]

I have seen these connectors go bad. You can use a safety pin to release the connector pins. Stick the pin in the front, you should see a channel for the pin. Maybe the contacts are dirty. Or go to the junkyard and clip off a different connector. Solder it on. Some parts stores have new connectors and the dealer deffinately has em

[Lee]

I know you did idle relearns but did the car suge during the relearns. Mine had major surge troubles so I did the relearn like (see below) and it worked.

 

From true cold engine start:

 

I started the car, put it in drive while holding brake.

As soon as it tried to surge, I shut it off (in drive).

 

Put it in park and started again, into drive, as soon as a surge began, off.

etc. ect. several times. I didn't worry about how long it ran each time, It never made 10 min anyway.

 

The times it took to surge were less each time I fired it up.

 

CURED. It's a free test. And who knows.

 

Mine never thru codes, just surged until it died, unless I put it in neutral. Then it was always happy.

[RareGMFan]

Ummm.....how did you shut off the car if the gear was still in Drive?

[Robby1870]

Ummm.....how did you shut off the car if the gear was still in Drive?

 

Plus, when it surges during an idle relearn, I always just let it figure itself out. 2 or 3 surges and its fine.

[Lee]

During the idle relearn, mine just surged up and down til it died, same as at a stop light. Turning the key off as soon as a surge started made the difference for me. Otherwise the relearn failed to help.

 

Key will turn off with car in drive. At least older cars do.

[RareGMFan]

I have 2 '89s, and 2 '90s. None of them allow you to shut the car off in anything other then park or neutral.

[MonteC]

I have 2 '89s, and 2 '90s. None of them allow you to shut the car off in anything other then park or neutral.

 

ill try it this morning and see what happens.

 

i havent gotten those tps readings btw.

[MonteC]

update: i CAN turn my car off in any gear, i just cant take the key out.

 

and ill get those readings this weekend.

[RareGMFan]

Wait.....nevermind, I got that backwards. I can't START the car in anything other then drive or neutral. :oops: Sorry....too many work hours fry the brain........I need a vacation. You may resume discussion.