1990 4.3 TBI crazy high idle

[Gerhants]

I have a 1990 c1500 with a TBI 4.3 and it idles really high. It has a code 22 for a bad tps sensor. I tried replacing it and other basic parts to solve a high idle like iac and new air filter. Neither worked, any ideas?

 

[ralmo94]

What diagnostic tools do you have available? Are you able to look at aldl data? How does it idle with the TPS unplugged? Possibly a bad wire going to the TPS? Should be a reference 5vlt reference ground, and signal between 0 and 5vlts based on throttle positions. 5vlt full throttle.

 

[1998_K1500_Sub]

I have a 1990 c1500 with a TBI 4.3 and it idles really high. It has a code 22 for a bad tps sensor. I tried replacing it and other basic parts to solve a high idle like iac and new air filter. Neither worked, any ideas?

What do you mean "neither worked"? Did the new TPS resolve the Code 22?

Offhand I might suspect you've a significant air bleed that's allowing air into the intake manifold.

Do you have access to a scan tool so that you can read / confirm the various sensor values and other parameters such as IAC position?

I have a few other ideas but I'm interested in your answers.

Too, others members may have more to add.

 

[evilunclegrimace]

TBI base gasket? It is just a guessing game without live data.