Expert opinion needed: 1.9 tdi fuel supply problem?

[deadcod]

I am new to this forum and hope somebody can help me. I am at the end of my (limited) knowledge. Our Audi A4 B6 (2002) 1.9 tdi runs normal (or actually very well) until it suddenly loses power and stops. Sometimes this is preceded by some shuttering. If I am driving downhill with no gas it sometimes just dies resulting in no power steering and assisted brakes. Nice! It usually starts again after a long try and then runs fine until happens again. It is no black smoke visible.


I have replaced the fuel filter incl. valve (twice), the flexible fuel lines (checked the hard plastic ones) and electrical harness for injectors. What else can I do before I take the injectors out and have them checked? How can I check the two fuel pumps (does it have one in the tank or just the dual vacuum pump?).

Many, many thanks in davance!

[ABangingDonk]

VAGcom scan?

Sent from my SM-G935F using Tapatalk

[deadcod]

VAGcom scan?

Sent from my SM-G935F using Tapatalk

Done that. Empty.

[nevo]

Disconnect the fuel supply at the fuel filter,get a jar and put the pipe in,turn on the ign(engine off) see if the lift pump is working.also get a extension on the pipe down lower than the tank,ideally you need a vac pump to syphon it down to see if there's any restriction from the tank it sound's like there's fuel starvation.

[deadcod]

Sounds like a good idea. Which pipe do I have to disconect? There are 4.

[nevo]

You should see arrows for feed and return,if they are gone, the pipes with the mickey mouse clip is the return,you will see the feed outlet going to the high pressure pump,use the feed to the filter.

[deadcod]

Sorry. Stupid question. I just follow the pipes...I will try that tomorrow. Thanks!

[monzaz]

Hi, no specific advice I'm afraid, just a suggestion as to another option. My 2002 A4 stopped suddenly a few years ago and it was the 'in tank' fuel pump. Audi specific, the pump cost then about £500. Hope it's not that?

[rowdy-999]

This ^, but you can get them cheaper.

[deadcod]

Thanks for all your help! In the the end it was a faulty relay that caused all the trouble. Cheap and easy to replace if you know what it is......