Having an odd issue with my '86 IROC. Motor is a mostly stock TPI 305 with exception of headers. The torque converter seems to lock and sometimes stay locked in all gears. At the same time the cruise starts acting up. It will floor the throttle after setting it or sometimes wont set at all. This has been an off-and-on problem over the last year or so. I have disconnected the plug at the trans and the torque converter stays un-locked but the cruise problem continues to come and go. I would really like to use the torque converter lock-up feature. It will work for a while and then malfunction. It dosent seem to matter if it is cold or hot or what sort of road I am driving on.

I have replaced the ECM (I have two spares) and it dosent help the problem.
Thanks!

 

I would start with your brake switches. I don't know which one the cruise is hooked to, but one or both of them come into play for both the lock up and the cruise.

If they are out of place or not mounted securely they could be moving around and/or giving incorrect signals based on where they are located as they are out of place.

A good and easy place to start with before getting too far.

 

I did check that. The cruise usually does stay engaged, and when it is engaged it usually does work. Its just that when it is it either surges or floors it. Thank you for the help! I figured everyone would be all over this one. Guess I have a "Stumper", huh? LOL, I have a friend who is an ase mechanic and he is stumped too!

 

We are kind of wondering if there is a "Module" that is connected to the ecm and also the cruise? Maybe a "Speed sensor"?

It is a cable-drive speedo...

 

Er.... Anyone?

 

Converter lock up issues AND no cruise,,,,,,,,,,,,,,,,,,2X on the brake pedal switch!

 

I checed the brake pedal switch, it's ok. My mechanic friend says that if the switch was hung-up then the torque converter wouldnt lock at all. instead, it is locked in all gears at any speed. Whatever it is thats causing the problem seems to have broken for good, as it is now a constant problem and not an intermittant one. Today on the way home it stayed in lock-up all the way through the gears and stayed locked up when I got on the brake during turns, seemed to be "Bogging-down" like I was driving a manual in too high a gear for the slow speed.

 

Anyone? IS there a V.S.S?

 

disregard

 

It the brake switchs. They can look ok but you have to pull them out and you will see they are cracked.

 

Ok, I will replace them with some extras from one of my parts cars and go from there. Thanks Guys!