Fuel pump issues?

audi
a6

#1

Sometimes I have problems starting my 2006 Audi A6 3.2 with 58,000 miles on it. When I turn it over to start it, sometimes it will continuously try to start without fully turning on. The engine will try and try and try to start, but won’t fully turn on. From what I have read and teh advice I have got in here it seems that it may be the fuel pump relay. If I turn the key without trying to start the car and let it sit for a couple of seconds and then try to start it I usually don’t have any problems.



I have also noticed that when I try to accelerate just after starting it that there tends to be a hesitation in the engine and it won?t accelerate correctly. Any advice you could provide would be greatly appreciated. Thanks!


#2

It does sound like a fuel pump, perhaps a weak pump (low pressure) which could explain the hesitation and also getting a good start after sitting (builds up the pressure). If you take it to a mechanic, they can put a pressure gauge on the fuel line and test the pump pressure.


#3

Yes, it sounds like a fuel pump problem although it can be very difficult to distinguish between fuel pump and ignition (electrical) problems based just on the pattern of starting problems.

I think the normal approach to this is to replace the external fuel filter (if there is one) just because it’s usually not very expensive, isn’t too hard to replace, and it probably hasn’t been replaced for many years and a zillion miles. If that doesn’t fix things, the fuel pressure is measured. That’s very easy on most American cars which have a schraeder valve specifically intended to connect a pressure gauge. It’s harder on many foreign cars where the fuel delivery hose has to be rerouted through an adapter. If the fuel pressure is OK and pressure doesn’t leak down very quickly (There will be a vehicle specific specification for leakdown rate) then one proceeds to worrying about ignition problems.