1995 Civic DX - No Power at Fuel Pump (I have done some troubleshooting)
The car ran fine with no issues last week and I had to swap the motor, I have done so many other times with no issues. I hooked everything and went to start it and I am not getting power to the fuel pump.
All tests were done with the key in the on position.
Underhood fuse #31 - Its fine
Under-dash fuse #12 - Its fine
Main relay wire harness pin #1 (Power) - Its fine
Main relay wire harness pin #2 (Ground) - Its fine
ECU connector plug A port 26 - Its fine
ECU connector plug A port 25 - No Power
ECU connector plug A port 23/24 (Ground) - No Power.
Main relay wire harness pin #7 - No Power.
I do not have a spare main relay to swap out but from the testing, I am leading that way. It doesn't look like its switching.
The CEL is staying on when I use the jumper harness to test codes and nothing changes/flashes.
Am I missing anything else?
All tests were done with the key in the on position.
Underhood fuse #31 - Its fine
Under-dash fuse #12 - Its fine
Main relay wire harness pin #1 (Power) - Its fine
Main relay wire harness pin #2 (Ground) - Its fine
ECU connector plug A port 26 - Its fine
ECU connector plug A port 25 - No Power
ECU connector plug A port 23/24 (Ground) - No Power.
Main relay wire harness pin #7 - No Power.
I do not have a spare main relay to swap out but from the testing, I am leading that way. It doesn't look like its switching.
The CEL is staying on when I use the jumper harness to test codes and nothing changes/flashes.
Am I missing anything else?
Last edited by Mark Williams; Jun 12, 2018 at 08:33 AM.
don't buy a new main relay.............fix it.
pop top on it.
resolder the main joints.
google this. covered 9234785x times. very easy fix.
pop top on it.
resolder the main joints.
google this. covered 9234785x times. very easy fix.
I am going to bench test the relay to see if it is working correctly first, then I will try the solder. I do not see a crack visible but I guess it maybe had to see.
Resolder the relay. It was a lemon part. Every one eventually needs resoldering even if it isn't acting up at the moment.
The ECU ground wires on the thermostat are easy to forget when swapping the engine.
Once you're sure the main relay, ECU grounds, and power system are OK, it could be the ECU itself. Turn the key on and leave on for several minutes to see if the CEL ever goes out. If it does and the car can then be started, you have a common ECU problem where it is slow to boot up. This may be fixable by replacing capacitors in the ECU.
The ECU ground wires on the thermostat are easy to forget when swapping the engine.
Once you're sure the main relay, ECU grounds, and power system are OK, it could be the ECU itself. Turn the key on and leave on for several minutes to see if the CEL ever goes out. If it does and the car can then be started, you have a common ECU problem where it is slow to boot up. This may be fixable by replacing capacitors in the ECU.
Thanks for the replies. When I was doing the testing of the wires I had used a test light and my grounds showed as fine. I noticed, later on, I had the negative battery grounds both on the body side and none on the transmission. I moved the long one to the transmission and as soon as I did everything started working correctly. The main relay and ECU are fine and my thermostat connection was cleaned 10x times.
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