4l80e and a carb

[1badeagle]

I'm looking to remove the tbi from my 93 k2500 suburban, but I want to keep my 4l80e. I've been told that I can install a hei and carb and travel the harness installed and the 4l80e will still function normally as long as I have a rpm signal, map and tps. Does anyone know if there is any truth to this?

 

[Texcuda]

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.

 

[TylerZ281500]

map is useless at that point just need TPS and RPM signal, but why?

 

[moondog1]

Sorry to bump an old thread but are a lot of people doing this? I'm planning for a motor swap, with a carb likely, and curious to know if certain carbs are better for this application of having the factory computer shift the trans still. Thanks.

 

[stutaeng]

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.

 

[Supercharged111]

Sorry to bump an old thread but are a lot of people doing this? I'm planning for a motor swap, with a carb likely, and curious to know if certain carbs are better for this application of having the factory computer shift the trans still. Thanks.

It's a matter of preference. I'd rather tune the EFI than have a carb given the option. The stock PCM shift points may not match up with the new motors needs, so no matter what you'll be tuning something with a computer even if it's a standalone trans controller. Stock computer will do it with RPM and TPS running trans only.

 

[TagAllen]

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.

 

[Supercharged111]

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.

Have you tried removing the bulb?

 

[Tex57]

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.

how did you hook the TPS up to make transmission shift?

 

[TagAllen]

I used a tps kit for holley carbs from summit.

Holley 534-202​