92 civic vx Fuel Pump issues...Helppppp

Technical Topics specific to the Hatchback body - NOT where you post pics/build specs of your car.
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92 civic vx Fuel Pump issues...Helppppp

By djhart88
- Sat May 26, 2012 2:33 am #306264 My 92 civic vx will not crank. I have a b20b/b18c1 head. The other day my fuel pump would not come on so i started looking into the problem. here is what i have done so far.

-Jumped the Main relay from 5 & 7 and tested for voltage at the fuel pump connecotr and the connector that attaches to fuel pump. Tested good

-Tested my main relay from the haynes manual and it tested good.

-Continuity check of all wires attaching to main relay. All wires good.

-i wired the fuel pump straight from battery and it worked.

- New fuel pump same issue. have to wire from battery

-Checked fuses 18, 24, & 31 all good none blown

As of now i have it wired into option 4 on the fuse box and my car cranks as long as i have the headlight on.

the main problem is that the fuel pump will not come on when i have the connecter plugged in. everything else works great. Car cranks with no issue as long as i am running straight from battery to fuel pump.

Any help to why my fuel pump is not turning on with its connector would be greatly appreciated.
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By teal_dx
- Sat May 26, 2012 3:25 am #306268 The harness to the fuel pump has a ground wire that connects somewhere near the base of the driver's seat (I can't remember exactly where but it's closer to the door opening)
It's a long shot but maybe the ground connection is not very good due to corrosion. :?

Did you take the cover off of the main relay and inspect all of the solder joints on the circuit board for cracks? When the weather gets hot, it causes things to expand/contract which makes the main relay work sometimes but not others. The cracks would be barely visible w/o a magnifying glass.

Usually at the start of every summer we get a lot of threads about the main relay not working, most of the time it is solder joints on the board that have cracked over time. :thumb:
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By djhart88
- Sat May 26, 2012 3:31 am #306269 I found the ground you were talking about. Ground was good i took of the screw and wire brushed the area and cleaned it up and still nothing.tested area with a multimeter it is a good location for ground

I took of the cover and looked at main relay no signs of faulty relay. plus i have 3 brand new ones and it still doesnt work.

:cry: :cry: :cry:

By EJ1_MK
- Sat May 26, 2012 10:51 am #306293
elrompetoto wrote:Ecu

Try another ecu


If this doesn't work check the wiring in the connectors to make sure that the pins are all in the correct locations and there is no breaks there. These wires are not covered up very well once you get past the drivers seat under the carpet. Would not take much for someone to step on them or snag them even through the carpet. Sounds like a long shoot but you never know...
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By suspendedHatch
- Sat May 26, 2012 7:39 pm #306316 Test the wire from the ECU that triggers the main relay. Either the ECU isn't sending the signal or the wire is bad and it isn't getting there.
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By djhart88
- Sat May 26, 2012 8:17 pm #306322 Tried swapping ecu. Same issue. However when I plugged old ecu back in fuel pump came on and car cranked. When I turned the car off and tried again doesnt work again. Wire from ecu is working as well and reaching relay but fuel pump still off :?
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By djhart88
- Sat May 26, 2012 9:50 pm #306333 Ok put ecu in friends hatch with a gsr and it cranked right up. So the ecu is not the issue. :?
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By suspendedHatch
- Thu May 31, 2012 2:43 am #306773 This has all the hallmarks of the infamous main relay intermittent failure. Take out your main relay, pop off the case, heat up the solder joints with a solder gun until they melt, then let them cool off and re-solidify. Plug it back in and send me a dollar.

Everyone with a 88-01 Honda/Acura should do this.
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By suspendedHatch
- Thu May 31, 2012 2:50 am #306774 Some electrical checks will come out okay even when there's a problem because it doesn't take much to allow a slight electric connection ie what a multimeter puts out, however, when you try to put real amperage through the same circuit, there's too much resistance for it and whatever load you have on it, ie fuel pump wont run.

Or in the case of the main relay, that fucker will click when you test it, but do nothing when you're trying to start your car. Anyone who has ever tried to demonstrate an electrical gremlin to a technician knows what I'm talking about. :)
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