Hey guys, I have a '91 V3500 3+3 with a 4L80E trans and TBI 350. My question is—does the tranmission run off of a completely seperate control module, or is it tied into the truck's ECM? The reason I ask is that I'm going to be swapping-in a GMPP ZZ4 engine, and I'll be using a carb in place of the TBI system. Any other potential problem areas with the change from FI to carb?
CK5
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4L80E . . . seperate control module?
- Thread starter point-five-o
- Start date
run a return line pressure regulator on the fuel lines and set to psi you need for carb. then run power wire for relay to key hot /crank and that will run the fuel pump relay . and need diffrent dist as tbi uses aits own distributor .
and yes tbi and tranny same computer. can get custom stuff done to run as stand alone . or find rare 6.5 4l80e stand alone computer.
but this seems to be the best and most options . http://www.usshift.com/index.shtml new name same product we use to call opti shift. read up on it its awsum. few guys here running one and like it.
ya its a burban but read here for BIG bbc swap with 4l80 and that controler. http://coloradok5.com/forums/showthread.php?t=265741
and yes tbi and tranny same computer. can get custom stuff done to run as stand alone . or find rare 6.5 4l80e stand alone computer.
but this seems to be the best and most options . http://www.usshift.com/index.shtml new name same product we use to call opti shift. read up on it its awsum. few guys here running one and like it.
ya its a burban but read here for BIG bbc swap with 4l80 and that controler. http://coloradok5.com/forums/showthread.php?t=265741
That is a lot of work to go backwards in technoligy, driveability, MPG etc...?
Why not just tune the EFI system for new motor? Less work, less dollar, better running...
Thanks for the info on the US Shift controller. Sounds like a good option for this plan.
That is a lot of work to go backwards in technoligy, driveability, MPG etc...?
Why not just tune the EFI system for new motor? Less work, less dollar, better running...
Well, I did a bit of research on this forum to try and educate myself on TBI modifications, and it kinda seemed like the consensus was the TBI systems work their best when left alone, and big modifications usually yield more headaches than anything else.
Since I haven't pulled the trigger on the ZZ4 motor yet, let me ask this—how difficult would it be to adapt my TBI system to a TBI 454? Are all the F/I and emission connections the same? Basically what I'm looking for is more power for towing, with one of the goals being keeping my existing overdrive trans.
TBI would need to be changed from the 5.7L you have to a 7.4L, may also need a little more fuel pressure to supply HP needs of engine so adjustable regulator. Then a tune, which to me is the easy and fun part!
Now you mention emmissions and your in NH, so what is required there? Even a perfect tune may not pass with a modified engine. Add to that would definatly not pass with carb...
Note on ZZ4 engine:
Now you mention emmissions and your in NH, so what is required there? Even a perfect tune may not pass with a modified engine. Add to that would definatly not pass with carb...
Note on ZZ4 engine:
TBI would need to be changed from the 5.7L you have to a 7.4L, may also need a little more fuel pressure to supply HP needs of engine so adjustable regulator. Then a tune, which to me is the easy and fun part!
Now you mention emmissions and your in NH, so what is required there? Even a perfect tune may not pass with a modified engine. Add to that would definatly not pass with carb...
Note on ZZ4 engine:
Thanks—the big block TBI swap sounds a little more straightforward. Since the 454 was an option in my truck, could I simply purchase the appropriate fuel pump to make sure the pressure is correct? Are the ECM and wire harnesses the same?
No emissions checks for OBD1 and older vehicles here in NH. Live Free or Die.
Harness, ECM and fuel pump are same. Swap TBI, plug and play with 7.4L chip to start tune of modified engine.
Awesome, this sounds like the best route for me. Thanks for your help!
