mathewb20

93 civic si, b18b turbo. theres no power to the fuel pump. power from the ecu and the relay, checked all fuses in the car and nothing is blown, tried 3 different relays and nothing. checked every ground, main ground on thermostat housing, all good, there is ground but no power at the pump. Please Help, I am now clueless and running out of options! Its a Wallbro 255 fyi.

Former User

How did you test fuses 24 (dash) and 31 (hood)?

If you unplug the main relay connector and jump terminal 1 or 5 (with key ON) to terminal 7, does the fuel pump run?

mathewb20

1 to terminal 7 turns on the fuel pump

virgineg6

Do any of the pins look recessed?

mathewb20

No not that I can tell, I have tried many different relays, and another ecu.

Former User

What about 5 to 7?

mathewb20

5 to 7 also works.

Former User

In the unplugged main relay connector, does terminal 2 have continuity to body ground? If so, reconnect the main relay plug and unplug ECU connector A. Turn the key to ON(II) and then ground ECU connector terminal A7. Does the fuel pump run?

mathewb20

2 has continutity, but A7 doesnt work.

Former User

You have found a problem with the A7 test. The fuel pump should have run. Was the key in ON(II) for the test? Try the same test on A8.

Then test for continuity between ECU connector terminal A7 or A8 and main relay connector terminal 8. There should be continuity for both.

95EG2

MAIN RELAY

Jeffreywbaker

I was following this thread and you had solved the problem at the A/7 test, but my fuel pump comes on when performing A/7 test....
So, please tell me where to go from here

mk378

The ECU drives A7 to ground as it boots up. So there's a good chance your ECU is not running. The Check Engine light should come on and go out when you turn the key on and don't start. The spark plugs should fire when cranking even if there is no fuel.

Check the ECU grounds on the thermostat housing. Check that all power pins on the ECU have power.

Jeffreywbaker

Okk, I have checked the grounds and they are good, it seems to be an intermittent problem/condition as at times whenever the check engine light comes on and goes back off the fuel pump does kick on.
But now, this week since I have tried to figure out what is going on with it the check engine light comes on and stays on.
I will check power pins to ECU tomorrow.
Thanx a million.

mk378

OK let's first back up and make sure you have re-soldered the main relay. Do not do any further diagnosing on this problem until you are sure the main relay is good.

If the CEL doesn't go out, leave the key on for up to several minutes to see if the CEL eventually goes out and the car can be started. If that does happen, replace the ECU. Although bad ECUs are relatively rare, this particular symptom of delayed start up is a common way for them to go bad.

Jeffreywbaker

Yes, main relay was the first thing that I checked out, I ordered a new 1 and I re-soldered the old 1 while waiting for new main relay to come in, they both actuate whenever key is turned on.
I'm gonna get back on it whenever I get home from work today.