Audi 100 2.3E avant 1988 fuel pump - part 2

Do you have the manual for the car / K-jet?

I would guess the extra hose is for the tank vent - probably runs to a charcoal cylinder somewhere.

Nedavno Doki napisa:

No, I do not have a manual for the car, but you are probably right, it might be for the tank vent.

Is fuel pump serviceable part, or you can only replace with new one?

Don't know your vehicle but assuming injection many run the pump for a few seconds then stop (to prime the system) if you just switch the ignition on. They stop to avoid flooding the engine if an injector is leaking and also to avoid running down the battery as they take a fair bit of current. Cranking the engine causes it to run as well, and then a signal from the ECU when it starts.

A battery charger isn't designed to do this and may well not provide sufficient current. Can you try a good battery instead?

Feed from tank?

Nedavno Dave Plowman (News) napisa:

How much current does the fuel pump draw? I think that it is fused with

I'll try with the good battery tomorrow.

Mine is fused at 10amps - but includes a series resistance.

Very few domestic battery chargers will supply a genuine 15 amps - regardless of what they claim. 8 amps or so peak is more like it even with an expensive one.

I turned the metal ring anticlockwise, disconnected three hoses, and pulled all out.

I connected fuel pump to the battery, and I could feel a sort of click. I reversed the polarity, and did that several times but no luck. I than taped the pump with a wooden stick while it was connected (correctly and reversed polarity), and after a few taps it started do work.

Returned the pump and everything else as it was, and the car started nicely.

Perhaps I have to start it more often (I do this once a month). But I do not have spare battery, so I have to transfer it from the car I use regularly. Any other thought how do I prevent this to happen again?

plenty of clean fuel in the tank should stop it, you could even add a small amount of diesel to a tank full to give a bit of lubrication. an old weak battery should still have enough power to spin the fuel pump

Nedavno Mrcheerful napisa:

I try not to add to much fuel in it the tank, as it was suggested (in this newsgroup IIRC) that it can turn to jello. There is enough fuel that fuel pump is not dry.

The car is not used, so I just start it up once a month.

Since the car is not used I connected battery to a charger that is controlled by a timer, so it automatically turns on and off. But while I was away for a month timer broke and the battery was destroyed.

There is no good reason not to keep the tank full, a full tank suffers less from condensation (which is what will have caused the pump to stick), petrol will not deteriorate for at least a year (in the UK probably two years would be Ok), you could then drain and refill, use the fuel up in another vehicle, that way the only cost is the labour to change it.

Buy a modern charger and it can be left connected indefinitely without harm to the battery or significant running costs.