Fuel Pump Always On

beancounter1 · 04-09-2006, 11:48 PM

I have a manual EA S Pack (10/1989) with multipoint injection.

When the key is set to "accessories" (engine OFF), the fuel pump is constantly on and pumping fuel. I can hear a hissing sound near the fuel regulator. I cannot see any leaking fuel. I assume that the pump is pumping fuel through the lines and back to the tank. When I pinch the fuel line going into the regulator, I can feel fuel going through it and this forces the pump to labour.

I thought the fuel pump was only supposed to start momentarily when on accessories - just so that it could build up pressure.

The car seems to start and run fine.

Why would the pump be constantly on ? Would the regulator be faulty , or is there a valve somewhere or is there a wiring problem with the fuel pump ?

anakha · 05-09-2006, 11:29 AM

I had an issue with an in-line pump some time back and due to some very dodgy action by an auto electrics shop the wiring at the relays was altered so the in-tank pump runs full time when the key is set to on instead of the brief prime and then off unless engine is running. Perhaps something similar has happened with yours.

Take a look at the wiring and compare it to the factory manual if you have one.

This prompts me to ask does anyone know of a good auto electrical shop is Sydney I could talk to to re-wire some connections in my ED and also run the wiring for a battery box I have that I want to setup in the boot?

beancounter1 · 07-09-2006, 11:26 PM

I have looked at the wiring and yes someone has done some dodgy work. A wire has been run from the accessories circuit directly to the fuel pump in the tank, causing it to be constantly on when the key is on accessories.

The genuine wiring still seems to be plugged into the pump, but the pump does not work when I disconnect the "new" wire. I guess this means that the fuel pump relay (or something else) could be broken. Where do I find the fuel pump relay and how do I test it ?

Car won't start or run without the fuel pump going.

beancounter1 · 09-09-2006, 12:54 AM

I have found the fuel pump relay and replaced it with a working unit from another EA falcon. Unfortunately, this does not solve my problem. Still no power to the fuel pump via original wiring. I can power the fuel pump from the relay by running power down the line. I have constant 12v power at the relay. This leads me to suspect that it is not getting a signal to turn the pump on. I assume the signal must come fom the ECU computer ??

The wiring diagram talls about a "fusable link". Where are these located ? Could this be the problem ?

blownba · 09-09-2006, 01:24 AM

No it wouldnt. It sounds like they wiring may have been modified at some stage possibly
The fusible links are located at the positive terminal of the battery they bolt up to the bus bar but it aint them.
The relay is a tachometrical relay which means it gets a signal from the negitive of the coil which tells it when the engine is running. so when you turn on the ignition it should only power up for a 3 second prime and it shouldnt power up again untill it recieves a coil pulse. And incidently the relay should only power up in the ignition position not the accessories position. The relay also has a constant ignition power supply I believe but the earth is switched to turn turn it on, i believe. I can get the wiring diagram and test proceedure for it tomorrow from work if you like. I dont know it offhand.

beancounter1 · 09-09-2006, 07:12 PM

Thanks blownba.

It would be great if you could get me the wiring diagram and a test procedure for the relay and the system.

There IS a contant battery + source going to the relay, and this is working. The wire from the relay to the fuel pump also works. This leads me to believe that the problem must be no signal coming to the relay (from perhaps the coil or ECU) to tell it to turn on momentarily or permanently. I thought the 3 second prime, engaged in the accessories position ???

My email address is drew@big.net.au if you wanto to send me the wiring/test info. Thanks.

blownba · 09-09-2006, 09:06 PM

**** ya gonna hate me I damn forgot about it. I'll get it for ya on monday sorry man. And the pump should never start inthe acc. posistion.