Efi'ng Annoying

[Guest Pilch]

Hi all, I'm having trouble with the supply to the in tank fuel pump on my series 3 EFi.

The problem is gradually getting worse but can't rely on it not letting me down at the mo'

There are two lives ok at the Relay (standard sierra loom/fusebox) the relay is clicking in ok every time but there is not a live supply to the pump at the rear every time on switch on. This is pretty hard to check as the pump is only live for a few sec's at every turn on. When it does work she starts and runs fine.

What controls the pump initially running for a few seconds?

Where should I start checking for the fault?

Regards

Richard.

[Guest Ant]

The pump is powered from the fuel pump relay, which is itself powered from the ECU. The ECU sees the ignition go on and so it turns on the fuel relay for about a second or so. It then turns it off and won't turn it on again until it sees the engine turning. It knows that the engine is turning from the hall effect sensor on the side of the dizzy.

 

So ... trace the circuit from the battery, through the fuel pump fuse and through the fuel pump relay, then through the inertia cut off switch, and to the pump. Then trace the ECU wire to the fuel pump relay.

 

If it's an intermittant fault then how about wiring a test light into the fuel pump side of its relay, and to the ECU supply to the relay. That should allow you to identify the fault as either being in the relay, in the pump circuit, or in the inertia switch. You could also try jumping 12 volts onto the line from the ECU to the relay and see if the pump starts.

 

Hope that helps.

 

Ant

[Guest Julian B]

Hi

 

I had the same problem, which turned out to be a poor connector between the inertia switch and the pump.

 

Going back to the light bulb trick i would use two. 1 on the out put of the relay and 1 on the input to the pump. The only reason i say this is that you can have a faulty pump which can seize up giving the same effect. Both lights on Duff Pump????

 

I found the fault on mine by removing the relay and jumpering out the relay switch contacts. This gave a permanent supply to the pump. It was just a matter of finding the duff connection then.

 

Good Luck.

[Guest Pilch]

Seem to have sorted it just the small brown relay for the engine management (E on the fuse box lid No 55 in the Haynes manual)

swapped it for another one and all seems well so far. got to do a few local runs first to make sure all is well.

Like nice easy fixes.

Thanks for the help

Richard

Royston

[Guest Pilch]

:angry: Bo**ocks! Lasted all of about half a mile then packed up again.

Luckily it restarted after a short while and managed to get it back home.

After much pulling things apart and scratching my head and cursing, lots and lots of cursing, I finally think I've tracked it down. Seems the relay wasn't at fault but one of the terminals it plugs into had pushed out of the back of the fuse box and was only contacting intermittently.

Test probe was slightly longer than the spade on the relay so was checking out okay

A couple of test runs over the next couple of days and i'll be off to Detling in it on Sunday.

See you there

Richard