Gentlemen....

I swapped an LY6 into an 08 Avalanche using the stock 4L60E trans and have ran into a tuning hurdle. Is the LY5 and LY6 throttle bodies the same?

While tuning (HP Tuners) under WOT the throttle body blade fluctuates between 55%-88% and we've not be able to solve the issue. We verified pin locations, and other than locating an LY5 TB not sure what to do.

Any suggestions?

 

Apparently when swapping from an LY5 to LY6 with dbw it requires the trans, pedal, and tb signal to match. LY5 tb solved the issue.

 

Both engines should have the exact same TB's. I have a friend that did it and it was a direct swap. Maybe you have a bad connection somewhere??

 

So at this point I've changed and or verified the following: New fuel pump, coils, wires, spark plugs, and injectors. Luckily we had a spare engine laying around. Anyhow, the cam is a comp 54-426-11 222/224 566/568 on a 112. The issue is the engine is surging on startup....and at random. Are the sensors the same between LY5 and LY6? Is this issue strictly tune?