My 90 gs has been having trouble starting recently and I noticed the pump was not priming, so I went ahead and put in a new pump since it was getting noisy anyway, and it started right up, then just stopped priming again the next day. I figured maybe it was fuses and checked all those before and after the new pump and all were intact, and threw in a new mfr to see if that helped, still nothing. I’m kinda running out if ideas, so any help would be greatly appreciated. I’m pretty handy with cars but not great with electrical stuff, so bear with me please.
i’d say to try another mfr that you know has worked in another car. also, make sure that the plug connectors are not coming out of the socket or something.
How did you check the fuses, did you test with a meter or test light or just eyeball them?
Do you have a multimeter, if not get one, even a $20 one from Radio Shack will do the job.
There are a number of reasons why the fuel pump does not prime the fuel system, a multimeter is the easiest way to find what that problem is.
Possible problems…
Bad fuel pump, probably not as you have changed it.
Bad PGM-FI Main Relay, also changed.
One of the above could still be bad.
Fuses, unless checked with meter or test light.
ECU/ECM, controls fuel pump relay.
Connections, there are a lot of them.
Wiring, there is a lot of it.
Start by testing, [with a multimeter] for power and ground, [yellow/black and black] at the fuel pump plug.
If no power move to output of PGM-FI Main Relay, there are two yellow/blacks, one is the output from the injector relay, it will be hot when ign. switch is in run or start, the other is the fuel pump lead, it should be hot for a few seconds, [priming] when ign. switch is turned on.
If no power move to the inputs…
Black- ground
Black/yellow- 12V+, [hot in run and start] fuse 24 - 15A.
Yellow/white- 12V+, [hot at all times] fuse 38 - 10A.
Blue/white- 12V+, [hot during start] fuse 18 - 7.5A.
Green/black- ground output from ECU/ECM to fuel pump relay, ground for a few seconds when ign. turned on and constant when car running, DO NO test this lead with a 12V test light, the other leads can be tested with a 12V test light but a meter is better.
Recheck the fuses with a meter or test light, they can look good and still be bad. 94
All my fuses were good, my mfr works, and all my wires have good continuity, so I figured I’d check and see if maybe it was my ecu. I ran a jumper wire from the chassis to the black/green wire on the mfr and the car started up, so from what I understand this means my ecu is fried right? If there’s anything I’m missing please let me know and thanks for the help.
Either ECU is toast or there is a connection problem between the ECU and the PGM_FI Main Relay, try running a jumper from the ECU to the PGM-FI Main Relay and see what happens. 94
Sounds good, hopefully I’ll have this tracked down soon, thanks for all your help.