i want to convert my iroc back to using the ecm for tcc lockup instead of buying a lockup kit or non lockup converter, ect. the harness from the trans is still there located at the rear harness area of the engine. which wires do i need to connect to the ecm so it can work the way it used to. i didn't intend to cruise on the highway when i removed all this stuff but now i am cruising.

 

For the most part the ECM uses the TPS, VSS, and CTS for TCC lockup. Also included is the 4th gear switch in the tranny. It will probably need the distributor reference pulses to know that the engine is running.

RBob.

 

thanks rbob for the quick reply. i didn't mentioned it but i converted the tpi to carb, so there is no tps or distributor signal. i replaced the speedo cable with a mechanical one that was different than the original, and vss, well it is in the instrument panel but i don't know where it gets its signal. i don't know what cts is. i guess there's no hope in using the ecm then.

 

The CTS is the engine coolant temperature sensor. The ECM waits for the engine to warm up before allowing the TCC to lock. Can fake it out with a resistor if need be. But that also means the TCC will lock up on a cold engine/transmission.

The VSS is an optical pickup on the speedo head. Most likely still there.

The lack of TPS is a show stopper. The TCC lock/unlock tables are based on TPS vs MPH.

RBob.

 

thanks, the tps is gone because of the carb swap. that means i'll have to consider a lockup kit so the trans won't get damaged. also i noticed the tach is about 1500 rpm way out also. i bet those sensors or their input is affecting the tach reading.

 

You could just rig a TPS onto the carb.

 

thanks, but for now i'll monitor the trans by driving under 55mph and hope that the trans cooler that i already have will cool the trans. my new tach shows 2200 rpm at 55mph which is safe i guess until i install a lockup kit.