Possible fuel pump failure?

[Perplexer]

Evening all,

S3 225 BAM 85k miles.

I recently had to be recovered by the AA as the car stalled and would not restart. The AA chap did a scan and it picked up brake light switch (has been on list to do for ages) and an immobiliser fault. I recognised the immobiliser issue may be down to the key due to having starting issues a few weeks ago with the flashing yellow icon on the dash, so as I was close to home got hold of the second key and used that one.

Got no further with starting so he went to the next level of diagnosis which was to see if there was a spark - he sprayed carb cleaner in the intake pipe after the air filter while I tried to start it, which it did so this ruled out the immobiliser preventing starting. He then disconnected the fuel intake pipe on the left of the rail and again I turned the ignition but hardly any fuel came out.

The pump primes when I turn the ignition on and I have not noticed any odd sounds from the pump.

Could it have failed? Is this normal behaviour? Audi want £321.94 for a new pump. Fuel filter was changed about 50k miles ago. Any input appreciated.

 

[sirbobalot]

Have you ran the fuel tank right down some times you can drag the tank and it might of pulled some crap in to the filter and blocked it try disconnecting fuel line the in front of the filter see if u get fuel come out next would be the get to the fuel pump disconnect the out pipe get a mate to crank the engine see if the pump is pumping fuel if it is then the problem lies between the pump and the engine.

 

[Perplexer]

I replaced both senders recently but kept the original pump. Its possible that the tank was disturbed and the filter is blocked. Will test that tomorrow.

Thanks for the advice. Just planning for possible worse case scenario!

 

[sirbobalot]

Try euro car parts for a pump should be cheaper than audi. Or Audi tps is good on prices.

 

[<tuffty/>]

Perfectly feasible for a fuel pump to have failed... see them failing all the time these days regardless of mileage... age is the killer... replaced one on a BAM the other week...

Its worth looking over the FAQs as you would have found this that may be of help

http://www.audi-sport.net/xf/threads/how-to-audi-s3-fuel-pump-replacement-the-cheaper-way.207108/

<tuffty/>

 

[Perplexer]

Thanks. The price of the pump in the link is easier to swallow. Having done the senders its not too bad a job, just that I filled up the night before I broke down...

 

[Nilz]

Fuel pump could be likely, have you noticed a buzzing/humming noise when you have been driving recently from the back, thats usually a tell tale sign that its on its way out.

 

[Perplexer]

Not noticed anything untoward noise wise, but that doesn't mean its not there. Looking at what people are saying about end of life (this is a 2002 car) its probably worth changing as preventative maintenance.
I will check to see if anything is pushed out of the fuel line pre and post fuel filter and also check the hoses on the pump etc.

 

[Alex C]

can fuel pump failure/deterioration be diagnosed by logging injector duty cycles (Block#??) with VCDS?

 

[Jenno007]

can fuel pump failure/deterioration be diagnosed by logging injector duty cycles (Block#??) with VCDS?

I saw a post the other day where someone's injectors were at 100% duty cycle above 5000rpm, and they believed it was due to their fuel pump. So I would say yes