87CamaroMan

Hello. Well my Camaro has been on jack stands for a few months now because I thought my Fuel Pump was bad. When I turned the key FP didn't prime. I also disconnected the rubber lines under the hood and no fuel would come out. So today I cut and access panel in the trunk pulled the FP and hook my trickle charger up the it and it was pumping no problem. I also changed the FP relay before that and nothing. Are there any fuseable links anywhere in the fuel pump circuit or anything I should check before I replace all the wiring. Or any other ideas. Thanks.

87CamaroMan

Well. I couldn't sleep so I went out the the garage to see what I could do with it. So I started tracing the wires. The grey wire is bad. There are 3 wires one black (obviously ground) one purple that goes to the float and the grey one comes from the fuel pump relay. And from there it splits off to 4 different wires. Well on is to the FP and one is the the relay. I tried tracing the other 2 as far as I could but the motor got in the way. I got one all the way to the firewall on the passenger side I am assuming that goes into the ECM, and the other I got to as far as the distributor and then it went down and have no clue where that one goes. I was trying to read the wire diagram in my Hanes manual but that was giving me a headache from what I can tell is that there is supposed to be a fuseable link. Well I didn't find one. I found some spliced duct taped wire. I was wondering if I could put a diode in the line that goes the the ECM so I don't fry that and just wire a power wire from the ignition into the FP so when I turn the key the FP has power. It has a return line so if its pumping to much fuel it will just bypass and go back to the tank. The FP is good its just that I can't get power to it. And other Ideas welcome. Oh and its a 1991 RS 3.1. I am just trying to get it running so I can move it around the garage. I am replacing some of the floorboards.

RFmaster

'Man

Warning - the following bypasses all safety features - use at risk!

To test FP relay to Fuel pump wiring you can temporarily bypass FP relay. Relay is mounted on the firewall next to master cylinder. You should see gray wire (#12 Gauge) and red-black stripe (#12 gauge) coming into a gray or black socket. These sockets use standard 0.250" female spade contacts. Pull out relay, get a #12AWG jumper wire with a male spade crimp. Push into a gray #12 AWG wire pin, the other end test touch to battery positive. You should hear fuel pump run.

//RF

87CamaroMan

I know its somewhere in the grey wiring.

RFmaster

'Man

Assume nothing - question everything.

If the fuel pump relay is not being energized by ECM the fuel pump will never run. Also, you have to determine if gray wire fuel pump relay socket to FP is in working order (i.e not shorted, or broken). It is a multi step troubleshooting process. Replacing relay will not prove if gray wire (switched output) is OK.

1) Determine if ECM can enable relay during initial key on sequence. Remove relay from socket. Get a test light of DVM. Look at the wires entering FP relay socket. You should have two big ones - these are used to supply power to FP. There are should two smaller gauge (#14AWG). Usually one wire will be black-white (ground) and the other will be dark green-white. The later goes to ECM Pin A1. Probe DVM leads between two wires and measure DC voltage. Cycle ignition key from off into run position. For 2 seconds you should get 12 volts. If you are not getting +12volts repeat with test lead connected to engine ground and dark green-white wire. If now you are getting +12 - check black white wire connection to ground. Check all grounds.

2) Checking fuel pump relay socket to Fuel Pump wiring (Gray #12AWG). With FP relay removed from its socket, measure resistance between gray wire and engine ground. It should not read 0.0 Ohms or open. There should be some resistance due to wiring and pump coil windings.

3) +12 volt supply. Measure input DC voltage at the FP relay socket - there should 12 volts present at black-red wire. Otherwise troubleshoot back to main fuse link.

//RF

87CamaroMan

Well what I've done so far before reading that. I cut the gray wire going to the fp from the relay and hooked it from the battery and it gets power so I know the wire is good. Its a new relay. I am going to check the other wires on the relay plug tomorrow. I just went and got some new FI line and FI line clamps to patch the lines. I will be hooking the whole fuel system up tomorrow and just try my best. I don't really have access to a digital volt meter and nor do I have the $$$ to buy one. I just had to drop 500 bucks to put oil in my house for the winter. Can I just run power from my acc to the FP so when the key is on it gets power. Or run it to a toggle. I plan on putting a V8 in the car next summer. I just need to get it somewhat mobile so I can move it around. I am getting the body and suspension completed before I put the motor in it. Thanks

RFmaster

A cheap multi purpose DVM can be found for less than $20.