firebirdjosh

iTrader: (1)

I went to work on my car and noticed the fuel pump didn't prime when I put the key in. The car won't start and I'm not getting fuel pressure. If I send 12V to the tan wire of the fuel pump relay I can hear the fuel flow (I assume that's what the noise is) and my Fuel Pressure shoots up to about 55psi.

I'm getting 12V to the Orange power wire, black is continuous to ground, and I get no voltage at red or dark green. Is there a common tie that I must have missed? How do I test those two wires (when are they hot)?

BigBadLou

iTrader: (3)

The red wire comes from the ALDL connector where you can jumper the fuel pump. Don't worry about it right now.
But put a test light on the green/wh wire and turn the key on - you should see it light up for 2 seconds (fuel prime). That's the wire from the ECM to control the Fuel Pump relay.
If the light lights up, the signal from the ECM is good and your problem is most likely the relay or connector.
If the light doesn't do anything, you might have a problem in the wiring from the ECM to the relay. (or you don't have a good ground on the light - happens often ).

Hope this helps.
Lou

thedoctorisin

i've got an 89 that seems to be suffering the same problem. along with the fuel pump my injectors are not pulsing, or the computer is not grounding them out. anyway let me know if you track down your problem.

BigBadLou

iTrader: (3)

I think it's time I create a few write-ups on troubleshooting of the standard problems such as no fuel, no spark, no injectors ... I smell a tech article coming.

Lou

thedoctorisin

agreed. i have spark though. i have the msd 6al ignition box and accel coil and im getting a tach signal on the gauge and at the ecm. i dont know if the msd would make that happen, but no fuel and no injector pulse... i was reading about a fella that had similar problems, and he just had a bad body ground, and the problem was resolved with a new negative battery cable to the body. thought i'd give it a shot as well, i've been chasing electrical issues for too long to doubt anything.

gapimpin

swap the relays for the fule pump and the a/c... i had the same problem on mine and it was just a shorted relay.

Trickster

look for 20 amp fuse located on right hand side of car, it is an inline fuse and controls the ecm and fuel pump relay.

firebirdjosh

iTrader: (1)

The 20A fuse is good and power is getting to the relay. I replaced the wiring to the relay and it works, not sure if that was the problem but we'll see if it acts up again.