2.5tdi, cut out.........

[Mackers]

hi all i have an A4 2.5Q Tdi, the lift pump was faulty and the car cut out on me the other day, the garage has replaced the tank pump, but it still won't start.... apparently the tank pump, STILL ain't pumping right..... any ideas PLEASE!!!!
Wayne

[adamss24]

If you have Vcds/vag-com i would scan the engine for fault codes and see the measuring settings block 18. In the first 2 boxes you will have power from the car and power to the pump's brain. If the 2nd field reads 0 then the fuel pump brain is dead and it either needs repairing (some companies do repair that (it requires some carefull soldering of a new line transistor) or the whole pump needs a rebuilt- at which point it will get a new ECU and aditional parts (advance solenoid,speed sensor,bushes and seals amongst othe parts !). Contact dieselbob as it's pumps are fully refurbished from £475 + VAT. If you're friendly and collect with cash (!) you might be able to get a discount as well but you'll loose your guarantee though ! Dont be tempted in repairing just the pump ecu, for the extra £200 quid get it fully refurbished !

[Mackers]

i don't myself, i'm sure they do, as the tank pump was diagnosed very quickly, now theres "low fuel pressure"

[adamss24]

The a4 has no lift pump, the tank pump is there just to keep the baffle full of fuel. The garage needs to look at the main injector pump !

[PAULF]

Check the clear fuel line after the filter to the HP pump to see if there is any air or fuel going to your pump. If you have good fuel flow, then it looks like your pump may have gone, but check your return first as they can airlock. If you have loads of air bubbles in the line, get some fuel flowing first.

Bleeding these can be a bugger, I use a large syringe on the return line - pretty much as ElsaWin says. You can put an inline squeezy-ball hand pump type primer before the filter, and pump until fuel comes from the return, or pour fuel down a funnel in a pipe held higher than the filter.

Check the black T-piece on the filter, I managed to nick the seal during fitment which was a bugger to find. I poured fuel over the filter, cranked it over, then saw bubbles and heard fizzing around the valve, and listen around the injector return pipes for hissing/fizzing as these can also cause grief

If you do get it running, do not rev it for 10-15 minutes. The aforementioned Diesel Bob advised me it can take this long to clear all the air from the pump and any cavitation at revs can be terminal.

If you do have to get your pump done, as Adamss24 suggested, go to Diesel Bob Tuning - Home. The cost will vary depending on what is needed, and I would advise getting the inectors done at the same time. It is not cheap, but worth doing.

[Mackers]

been fully VAG'D today, no faults found, plastic bit floating about the tank, so blocked pipes the Audi bloke recons..... this seem true??

[adamss24]

I've seen plenty muppets advertising as audi specialists ! Does the car starts on easy start ? If it does then there's a fuel shortage. Either you check the injector pump gets it's power in measuring block 18 or you tow the car to expel air. If the car cut on you i suspect the high pressure pump is faulty and there should be a fault code pointing to thet in the ECU, ussualy there are a few 00550, 00628, 01268, 01318 points to terminal failure...

[Mackers]

no fault codes came up,,, this was eventually traced to somat plastic breaking up and blocking pipes and all the way upto the fuel filter,

[adamss24]

no fault codes came up,,, this was eventually traced to somat plastic breaking up and blocking pipes and all the way upto the fuel filter,

So, is it running then ? Unless you had contaminated fuel poured from a plastic can then i don't see how the fuel pick up could get clogged with large plastic bits especially as the pump has a gauze mesh to stop debris being sucked in... Anything is possible but if the car is still not running then it's a fuel shortage...

[Mackers]

nah it's all good now :D :D jus £400 lighter lol