tjsilvasr

Got a problem with intermittent fuel flow on my sons 94 civic 1.5 L DX.

I did all the checks from fuses (ECU & ACG) to main relay and also checked ECU A7/A8 to main relay continuity is all good.

I got to the part that pin A 27 neg - to A 7 Pos + is there voltage for 2 seconds and I do. It is a solid 12 vdc forever now the book says replace ECU with known good ECU.

And yes I can force the Fuel Pump to work by jumping terminals 5 to 7 on main relay and it pumps fuel like crazy and pressure is great.

1) My question is if anyone knows what causes the voltage to stay high on the ECU ?

2) Can I change a component in the ECU ?

3) Or should I check something else before changing ECU ?

??? ANY IDEAS ???

Former User

Have you already resoldered/replaced the main relay and cleaned an tightened the G101 ground on the thermostat housing?

tjsilvasr

Yes I did, I even replaced it when the re-soldering didn't work. I also did a direct grounding of the main relay (terminal 2 neg -) to make sure the ground was good.

Former User

You have not provided a clear description of the problem. Is it that the fuel pump occasionally fails to prime and engine won't start? When this happens, is CEL code 0 thrown?

tjsilvasr

I think I got it, I got to looking closer at the ground and saw broken strands so I re-did both of them.

I did a new crimp/solder connecting and she fired right up.

I hope that was it, but I thought it was fixed a few times now so we'll see what happens.

tjsilvasr

Yes sir, the fuel pump occasionally fails to fire and engine wouldn't start, but no CEL code 0 in fact no codes at all.

Former User

Does the CEL work? Click the Codes link in my signature.

If CEL code 0 is not thrown when the fuel pump fails to prime and the engine fails to start, then the fuel pump is possibly bad.

tjsilvasr

I never saw a code 0 when the fuel pump fails to prime the system.

The fuel pump problem still exists. I went out this morning to make sure
everything was still working and button up but the fuel pump would not fire.

Yes I'm sure the CEL light works because I got a code 5 if I remember right when I was playing with the MAP sensor the other day.

Former User

Do you know how to read CEL code 0? It's a little tricky.

tjsilvasr

Hey RonJ@HT,

I figured out what you meant by code 0 is the 2 second check engine light you get when the fuel pump primes the system and goes off. If it doesn't go off that's what you call a code 0.

Well I did have a bad ECU and a good ECU fixed the problem.

I had a constant voltage between ECU terminal A 7 + pos and A 23 - neg when I turned the ignition on.

According to the book there is not suppose to be a voltage there (ECU terminal A 7 + pos and A 23 - neg) for the first 2 seconds when the ignition is turned on.

Time for a

tjsilvasr

I figured out what you meant by code 0 is the 2 second check engine light you get when the fuel pump primes the system and goes off. If it doesn't go off that's what you call a code 0.

Former User