92 c1500 service engine at high speed?

[elusive7283]

Hello everyone and I am glad to be a part of the community, pleasure to be here! This is my first post here and I do apologize if there is a thread on this issue that I'm having on my 1992 c1500 OBS. The problem that I am having is that my service engine soon light turns on only at high speed, when I drive around town the light doe come on at all. I have changed the map sensor and tps sensor but I'm thinking the EGR/EGR Solenoid, or the o2 sensor also need to be replaced. Truck runs awesome and no idle issues outside of the annoying service light, my truck has 157k on it.

 

[scott2093]

Did you see if there are any codes yet?

 

[elusive7283]

Did you pull any codes yet?

Hey Scott I appreciate the response, I managed to pull a code 22. Even after replacing the tps sensor

 

[scott2093]

Have you tested the voltages coming off the tps? Maybe a wonky connector?

 

[elusive7283]

Have you tested the voltages coming off the tps? Maybe a wonky connector?

I haven't done that yet and that will be my next step, thank you for the suggestion. Only thing I did was clean the connector on the harness with contact cleaner. What voltage should I be getting from the TPS if you don't mind me asking? Thank you

 

[scott2093]

Not sure why it's hard to find this thread..

Looks like you are looking for .5v ish between the dk blue wire and ground.with key on..truck doesn't need to be idling...but can be..

Then you want to gently ease the throttle and watch the voltage steadily climb with no crazy jumps or dead spots..up to about 4v
Maybe jiggle the connector while you're hooked up to make sure it's good.... put your meter on the 5v gray line and ground too and maybe jiggle, make sure it seems solid...

This still won't tell you if you have an issue upstream towards the pcm but at least you can start here...