BlueIroc-Z

iTrader: (6)

I am doing a 6.0L LQ4 swap in my '89 Camaro and I am going to be going with an LS1 gauge cluster and fuel tank. Now I figure there should be no problem wiring up the fuel pump to the same wires as the stock one, but my question is what to do about the fuel level sender wiring.

On the LS1 tank there is a 4-pin connector for the pump and level sender. The wires are described as follows from the 2000 F-body Service Manual:
(A) Fuel Level Input
(B) Fuel Pump Control
(C) Fuel Pump Ground
(D) Fuel Level Sensor Ground
So, the third-gen connector for the fuel tank has three pins (I think), and they are Ground, Fuel Pump Power, and Fuel Level Gauge... Now, what I'm wondering is can I just tie the two grounds in the LS1 tank harness together and connect them to the ground on the 3rd gen connector?

I would think it woul be fine, but the thing that is making me question is when I looked at the same connector in the 2001 Silverado 6.0L Service Manual the pinout listed a Fuel Level Sensor Low Reference instead of just a ground. It was my first assumption that "Low Reference" is just another name for "Ground," but I figure I'd better ask just to be sure...

So to sum up: I am wanting to use the stock 3rd-gen wiring for the LS1 tank, but I am going to be using an LS1 gauge cluster so I am keeping the LS1 Fuel Level sender. I then would use the 3rd-gen wire that originally went to the fuel gauge and run it as the "Fuel Level Input" to the LS1 PCM. And, my question is: Is it ok to tie the Pump Ground and the Sender Ground together on the LS1 tank?

Spike-Z

iTrader: (4)

As easy as pie. You guess it by yourself buddy . And you will have no problems using the 3rd gen wires with the 4th gen gauge.

cam-

Agreed. Seeing as you are using the fourth gen gauge it should work fine and ground is ground so tying grounds together is fine. Fuel level sender to gauge correct BUT I know LS1's use the fuel sender to PCM for EVAP purposes also and I have no idea how that circuit is run. I would wire this up exactly as you suggested and if for whatever reason the gauge functions wrong or not at all look into the EVAP circuit

BlueIroc-Z

iTrader: (6)

Yeah, as far as I can tell from the wiring diagrams and pinouts that I have, the LS1 sender goes to the PCM, then the PCM outputs "Class 2 Serial Data" to the gauge cluster which controls the gauge. I am probably going to have the EVAP system tuned out...

I'm just gonna wire the sender to the 3rd gen gauge wire and run it to the "Fuel Level Sensor Signal (primary)" pin on the PCM. I wonder if I should split it and run it to the secondary fuel level input too, or just leave that one out for now...?

Z28FAST1

I don't think tying up the (C) Fuel Pump Ground and (D) Fuel Level Sensor Ground will get your fuel gauge to work. Honestly, I don't think anyone has gotten the fuel level gauge to work yet when using an LS1 gauge cluster. I have all my gauges working except the fuel gauge which I am currently working on.

My research shows that (D) Fuel Level Sensor Ground on the plug is a ground that goes to the PCM. Look up the PCM pinout and you will find a pin for this ground: PCM Blue Connector Pin 23 (GRAY) Fuel Tank Pressure Sensor/Fuel Tank Sender Ground. Makes sense that it ground both for the pump sender and the evap.

Here's what i'm going to try when I get a chance:


Run (A) Fuel Level Input to PCM Red Connector Pin 54 (PPL) Fuel Level Sensor Signal; and
Run (D) Fuel Level Sensor Ground to PCM Blue Connector Pin 23 (GRAY) Fuel Tank Pressure Sensor/Fuel Tank Sender Ground.

I'll let you know if I get it working this weekend. Also, let me know if your way works.

BlueIroc-Z

iTrader: (6)

Yeah, that's what I was wondering. That's why I mentioned that the Truck Service Manual called the wire the "Fuel Level Sender Low Reference." I had a sneaking suspicion that it wasn't called Low Reference for nothing, that the PCM would need that wire.

But yeah, it sounds like your on to something here. Definitely post up your results.

Unfortunatly, I got aways to go before starting the swap on my car. I still have a few parts to accumulate and another car that needs some garage time before we can get going on the IROC. For now I'm trying to kind of work through the swap in my head, to figure out little issues like this sooner rather than later...