Help with 3 bolt 78mm DBW to 87mm 4 bolt DBW
 

I have a 2000 5.3 yukon DBW harness. It uses the same DBW as the LS1 vettes did. I am changing over to the newer 4 bolt truck intake and have a 4 bolt DBW throttle body off a 2008 chevy 6.0 pickup. It is a 6 pin TB.
I know there is a adapter harness for LS1 dbw 3 bolt to 4 bolt GTO TB. I copied the pinouts and here is my issue.

When hooked up to match the pinouts the throttle body snaps close and doesnt not function.
I swapped the TAC motor control wires and it opens up full throttle and when I press the pedal it closes. Its just reversed but functions correctly. Anyone know any tricks to get this to work?
Attachment 442704Attachment 442705

Only thing I can think of to do is switch the 5v reference and low reference pins on the throttle body. Will that short out the PCM?

Tried that and no luck, pcm still works so thats a plus. Im so close though! It just functions opposite:(

It has been a few years since I did mine, but I seem to remember the factory pinouts being wrong about something. I'll check the colors on mine for you in the morning.
The DBW on those trucks, weren't the same as the vettes, they were just similar. The blade motor was on the opposite side. If you are using a vette diagram that may be the problem.

OK please let me know

Anyone else have any ideas? Have all the parts ready to install

I checked mine and it is the same as your pinouts except I have a brown with white and blue/dark blue wires instead of black and grey. Dunno

Do you know what year vehicle your PCM is out of?

It is the original 2001 PCM for the truck. 0411

I don't have much to add, but I do know that the newer DBW setups don't use a TAC module. The ECU has a plugs that go directly to the pedal and another that goes directly to the TB. I don't know if that makes any difference, but maybe?

Andrew

I am doing something a bit different, later LS2 E40 pcm and pedal assembly with the early DBW tb. So far I can't get the TB to operate at all. I have a later 6 pin TB due to arrive any day. According to my experience and data I have seen so far the 2 styles (8 pin vs. 6 pin) do not play well when mixed and matched.