Question about wiring for LS3 and 4L70e transmission controller

[SeattleDiver]

Hi all,



I have been searching the internet and am having trouble finding the answers, so I thought I would ask here. I am hoping that someone using the same thing can help.
I have a Blueprint Engines LS3 376 with a 4L70e transmissions with a USShift Quick4 controller. The kit included everything but a wiring diagram for the engine harness.

The USShift controller needs 3 connections: Power, TPS, and Ground.

Two complications:
1. They say to break into the ground wire from the ECU AS CLOSE TO THE ECU AS POSSIBLE. Is this really necessary? And if so, how do I find which wire that is?
2. Which wire of the 6 wires coming out of the gas pedal is the TPS signal? I found a pin diagram but it seems to have two position wires.

Any help is appreciated.

[BRRT]

I can't help much here, as I'm running a TKX with my LS3, but the Throttle Position Sensor (TPS) is not on the gas pedal, but on the throttle body. Even if you are running a drive-by-wire throttle body, which it sounds like you are.

You might reach out to the folks at BluePrint. They should be able to tell you about the connector on the throttle body they provide plus the harness and necessary mods.

[PNWTim]

My experience with aftermarket items and the LS is they all want to run directly to the positive post of the battery (not realistic) and they all must have a preferred ground. While I personally found this not to be true it is wise to go as far upstream as you can to avoid interference with other processes but I wouldn't think this would be likely in your situation. I wasn't even aware the E38 had it's own ground per se since the harness I used had multiple ground points at the firewall, engine, etc. Jeff is correct re: the TPS - it's on the throttle body but can be traced back into the harness if needed.

Since it is USShift calling out the requirements, I would give them a call and see what they say.

[SeattleDiver]

Ok I will have to call USShift. This is the diagram they have for the TPS signal

208765

[Its Bruce]

2. Which wire of the 6 wires coming out of the gas pedal is the TPS signal? I found a pin diagram but it seems to have two position wires.

Any help is appreciated.

Didn't you get a document for the GMPP controller like this one: https://www.chevrolet.com/content/dam/chevrolet/na/us/english/index/performance/resources/installation-guides/crate-engines/02-pdf/ls-engine-controller-kits-all-naturally-aspirated-non-e-rod-except-lc9.pdf

It's the purple wire coming from the 12 pin bulkhead connector. Ref. page 4.

[SeattleDiver]

Didn't you get a document for the GMPP controller like this one: https://www.chevrolet.com/content/dam/chevrolet/na/us/english/index/performance/resources/installation-guides/crate-engines/02-pdf/ls-engine-controller-kits-all-naturally-aspirated-non-e-rod-except-lc9.pdf

It's the purple wire coming from the 12 pin bulkhead connector. Ref. page 4.

What the heck! No they did not! This would have made things significantly easier.
Thank you so much for positing it!!!!!

[Its Bruce]

You're welcome. There are revisions to that document. Chances are it's still the purple wire that you need, but it's worth asking BPE for the applicable paperwork.