Efjams24

1992 civic dx hatchback all stock automatic.

So randomly my car's fuel pump doesn't want to cut on as normal. First things first I replaced w/a known good main relay same issue. So curious I had a pal come down w/his car and we tried both of my main relays (one from my car, one from the junkyard) both worked in his car. It is wild because sometimes it wants to work and sometimes it doesn't.

I searched and come across this on another site----

"First check all your grounds including the main EFI/ ECU ground on the thermostat housing. Then check the ECU fuse (under hood) and IGN fuse (under dash). If they are good then move on to checking the main relay..

Remove your main relay and then do the test on the left side of this img bellow, but skip removing the rear seat and lid. Just jump 5 to 7 on the main relay plug, turn the key to ON(II), and then listen for whether the fuel pump runs.

If the pump runs, then do the same test, except jump 1 to 7 in the main relay plug. Does the fuel pump run? No need to turn the key to ON for this test the pump should run without your keys in it..

if the fuel pump runs on bolt tests then you have a bad main relay and you will need to replace it with a new one.

If both tests above fail then check the power wire to the fuel pump with a volt-o-meter set at 20v. have someone turn the key to ON(II) and the volt-o-meter should read 9.7v - 12.1v until the main relay clicks off. if there is power to the wire then fuel pump is bad and will need to be replaced."

So I did all of the above test. My fuel pump runs if 5/7 are jumped and fuel pump runs if 1/7 are jumped. My relay is good though because I've tested it in another car. I've actually tested 2 in my buddies car they worked but just not in my car. Would anyone have any idea what my issue could be? I know the clip on my fuel pump has a ton of that gunky paste stuff inside the clips.. maybe it causes an issue? Thanks for any help.

Efjams24

I went over everything today w/sun light. Still tried 3 different working main relays and nothing. I jumped 5/7 together and the fuel pump cuts on, I also jumped 1/7 together and the fuel again cuts on. I checked my ignition switch it all seemed fine, the wiring @ the fuel pump all seemed fine besides all that gunk in the clip like you find sometimes and everything @ the main relay clip seems fine.

All fuses are fine as well.. so right now I'm just lost as to what my issue is.

Former User

Does the engine start sometimes or never?

Have you cleaned and tightened the G101 ground wire attached to the thermostat housing?

If the G101 is fine, swap in a known good ECU if one is available to you.

Efjams24

I'll try both idea's. The car when I purchased it had no issues, then over the past few weeks it sometimes wants to crank up and sometimes does not. The main relay does the first click but the second click w/a fuel pump noise does not happen. Also the dash light's normally will turn off after the second click and they all just stay on.

Like the CEL and etc normally all go out after the pump primes and all but they just stay on.

Efjams24

Found my issue.. pal brought me an ecu to try and it fires right up. Just to be safe we tried mine in his car and it did not work. Thanks for the help again Ron.