Tech / General EngineWhy is my car making that sound? My car won't start! Combination questions? Don't see a board for your problem or have other technical or engine specific questions? Post them here!
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I wouldn't think so. The 4L60e is electronically controlled with it's own PCM - I would assume this PCM needs input from the car's ECM in order to know shift points and etc. If swapping to carb, there will no longer be ECM input from o2 sensor, coolant temp, distributor (swapping to carb can't use the cc dizzy anymore), etc.
There may be some kind of seperate PCM controller on the market that could get info from it's own sensors, but last time I saw one of these it was about $1200 JUST for the aftermarket PCM. Be much cheaper to get another TBI unit or rebuild the one you have.
Yes and no. We have a fleet of newer trucks all converted over to propane that still run an electronic transmission. The ECM doesn't control fuel to the engine at all. They use what's called a Superfix for alternate fuels to correct for any fault codes but you won't need that.
Because the ECM won't be controlling the injectors, most of the emission stuff can be removed but the ECM needs to stay to control the transmission. The only conversion you need to do is to modify a TPS sensor to tell the ECM what position the throttle is at so that it knows how to shift the transmission.
80's GM pickup trucks with TBI have a perfect TPS. It has a lever on it that can be controlled by a carb. You can either modify a bracket to have an arm on the carb directly move the lever on the TPS or remotely mount the TPS and use a cable/rod connected to an arm on the carb to do the same thing. It still needs to be calibrated with a scan tool. Idle is around 0.50v and WOT is around 4.50v.
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"The only conversion you need to do is to modify a TPS sensor to tell the ECM what position the throttle is at so that it knows how to shift the transmission."
Just what I was going to post. Yes you need to intall a TPS sensor.
It doesn't matter which side of the carb you mount it on. The majority of those style TPS rotate counterclockwise when looking at the arm. You can see in the top picture that the pivot of the carb arm is at the bottom and the pivot of the TPS is at the top. It's using a rod to pull the TPS and the TPS has an internal spring to help return to idle. The TPS is also adjustable so at an idle, the proper voltage can be obtained. These lever style TPS use a different plug than what's on a third gen TBI TPS but it can be easily adapted.
The ECM uses a 5 volt reference signal. It sends 5v to the sensor then sees how much voltage comes back. At an idle, GM TPS are around 0.50 volts and WOT is around 4.50 volts.
