Allroad 2.5 TDI not starting

[Tony Parker]

seem to have a lack of fuel, lift pump in tank has been replaced. does the injector pump, pull fuel from the tank. where should I start going to fix problem, has in the pass seem to run out of fuel when going up a hill.

[ceilidhalfie]

Have you run the engine recently? Did you notice over a period the engine was getting harder to start - especially if not used for a day or so? I had thisroblem on my 2002 Allroad and it turned out to be a crimped or-ring in the fuel filter. The injection pump is not good at pulling fuel from the tank - you will usually flatten the battery before engine will start. Very easy way to pull up the fuel (and check for leaks) is to put an electric pump inbetween the fuel filter and the injection pump - this will draw up fuel inseconds.
Have you replaced the fuel filter - again this will drain fuel back into the tank when you remove the old filter.

[Tony Parker]

Have you run the engine recently? Did you notice over a period the engine was getting harder to start - especially if not used for a day or so? I had thisroblem on my 2002 Allroad and it turned out to be a crimped or-ring in the fuel filter. The injection pump is not good at pulling fuel from the tank - you will usually flatten the battery before engine will start. Very easy way to pull up the fuel (and check for leaks) is to put an electric pump inbetween the fuel filter and the injection pump - this will draw up fuel inseconds.
Have you replaced the fuel filter - again this will drain fuel back into the tank when you remove the old filter.

car had been running fine, just hope in it one morning and would not start, garage replace lift pump, was all good for 2 days, would not start after sitting for about 5 hours. Filter was replaced at last service 5 months ago, if injector pump has trouble pull up fuel has anyone put in a inline pump to solve this.

[ceilidhalfie]

If there are no air leaks, no inline pump is required. Diesel will stay in the fuel lines. My Allroad also has the 2.5 TSI (AKE) engine. Can you see fuel flowing thru the clear plastic pipe between the filter and injection pump? Also common fault is leaking return lines from the injectors.
The inline pump is just a (very) quick way of priming the fuel lines whilst cranking the engine and, due to its force, very easy to see any fuel leaks (only run the electric in-line pu for a few seconds at a time!). When you get it running, the pump is removed and the fuel lines should REMAIN primed. If not, you have an air leak somewhere causing all the primed fuel to drain back into the tank.
I also was getting this problem after CORRECTLY changing the fuel filter. Now I use hose clamps on the two fuel feed lines into/out of the fuel filter when changing. So far, no longer a problem - engine starts first time. The electric in-line pump is insurance in event of fuel draining.
Hope this helps.

[bagpipingandy]

yep the lift pump just swirls fuel into a baffle chamber in the top of the tank for the injection pump to draw, but this line from the baffle to the injector pump needs to be full of fuel, any air and the injection pump cannot pull fuel. assuming the baffle chamber is filling ok suck the fuel from the tank at injector pump to get all air out, then quickly refit and crank over with injector pipes off, can take a lot of work to get the fuel flowing again, this is assuming everything else is ok :)

Andy

[Tony Parker]

Thanks for you input on this, lots of great stuff. We have tacked it down to the check valve on top of fuel filter, can see air in clear line to injector pump waiting for part to arrive from Singapore. Joys of living in this part of the world. will let you know how this works.