Fun Fuel Problem! Not pump. Relay?

[Tech12]

Obviously, I have a problem. Here goes: I was enjoying some twisty roads on the way home from a buddy's house in my 91 s13 with newishly swapped in 93 motor. I hit the top of second, shifted into third, and the revs fell all the way to zero. "Crap" I though. "something must have come loose when I shifted... Well, anyway, I pushed the car back to my friends driveway and started poking around. The car would turn over, but give no hint to actually wanting to start. I eventually discovered I had NO fuel pressure, so naturally, I diagnosed the problem as a dead fuel pump. Now, I'm out 90 bucks, in a Walbro, and the car still hasn't run. The fues to the pump is fine. When I turn the key, I hear nothing coming from the pump, but I can get it to prime if I put a jumper wire between the contacts under the fuel pump relay. Now then, the reason I don't know if it's the realay or now is because I have tried to stick various other green relays from other relay boxes into the egi pump relay, and still get nothing.

I know this is a long post, but I have searched and found very little, and I hoping that throwing all of this detail at you guys can help. Thanks in Advance-Lech

PS: For anyone searching about this kinda thing, here is a fun fact that took me a while to decode: EGI PUMP means FUEL PUMP so when you're looking for your "fuel pump relay" maybe this post will help you out.

[mss5413]

Are you sure that just because it is a green relay that they are interchangeable with the others?It should have the relay diagram on top of the relay.I've never had a problem like this, it is just a suggestion.

[Tech12]

yeah, all of the green relays had the same diagram. I kinda figured thats how they worked, colour coded, you know?

[mss5413]

Make sure that when you are interchanging relays like that, that it is not a relay critical to the car starting.

In other words, the relay may be good, but once disconnected, there's a problem.

[Tech12]

I'm pretty sure I tried the A/C relay, as I have ripped that system out of my car. Anyone have a definite answer that is I can jump the relay that means it is broken?

[Tech12]

bump?

[sdtouge]

maybe your fuel pump isnt grounded or something liek that

[Tech12]

I think I've figured it out. After much fussing and bypassing the relay to turn on the pump, I discovered that I had no spar either. I finally went to try to pull a code from the ecu and found that the light would not turn on for any kind of messing with the screw, and also my cel never came on. This leads me to belive that I fried the ecu somehow. I have a spare one at home I'll try when I get the chance. Thanks for all the help guys, I'll report back when I know more.-Lech

[Tech12]

nope, swapped the ecu and still nothing. I'm gonna try to take this to the main tech forum, maybe nistech can come up with something.

[navysnail]

look in my members rides gallery, i have a flow chart with step by step procedure for diagnosing fuel pump falliure

[Tech12]

Thanks, but I've already traced it back to the ecu not providing the signal to turn it on. In fact, it seems that it's just the ecu that doesn't turn on.

[NISTECH]

check ALL your fuses , if they are all good check all your power and ground supplies to the ecm. one is likely dead. when you figure out which pwr/gnd is dead trace that circuit and find the problem, could be the eccs relay is no good, try swapping that one out with a matching color and terminal realy. good luck