4l80e and a carb

[Medic0893]

I am running the Factory TBI computer on a 4l80e trans with all the fuel injection removed. yes the check engine light is on. No stand alone computer.

Any issues with downshifting under load at highway speeds, and not up shifting after the load is gone? I have to turn the key off and back on to get it to up shift after every hill… everything else about it works fine on surface streets, only at highway speeds. What TPS are you using? How did you set up the signal?

 

[Medic0893]

You need a stand alone controller for your transmission. Without the ECU for the TBI, the transmission won't work because the ECU controls both engine and transmission using inputs from the different electronics and sensors. Something like this: https://www.painlessperformance.com/wc/66501

It looks like this kit works only on 1995 and newer transmissions. Probably need to crawl under your truck to see the year of the actual unit if it is actually a 95...

If you can live with a 3 speed, the TH400 makes more sense for a carb setup. I think that's what most guys do.

I think I have to disagree, many people have successfully made the transition without a aftermarket TCM.

 

[Medic0893]

All true. I am currently using the B&M remote TPS hooked up to the factory TPS wiring and the purple wire from the distributor harness plugged into the tach terminal on my HEI. Leave the coolant temp sensor plugged in on the intake. That's all you need to keep the factory computer running the transmission. All the other TBI wires can be removed and taped up. Your check engine light will come on. There isn't anything you can do short of removing the bulb from the cluster.

What TPS are you using and what are the settings you’re using for the TPS signal?