Kevin Howe

I everyone, been a while since my last visit to hear. My 2.5 tdi is spinning over but not starting. Yesterday i replaced the fuel return line on one of the injectors but i think this is something else?? Have cranked with fuel lines loose to bleed any air and no fuel comes out. Fuel line to injector pump is full of fuel with no bubbles. Also I cannot hear any buzzing from the fuel pump. I checked fuse 28 and its fine what do we think I should check next? I read somewhere if i apply +12v to fuse 28 and hear pump its not the pump but the cars is still on the road so have sent recovery out for it. Frustrated in Sussex.

bilbo6209

I'm not familiar with the 2.5 but I spent many years working on my 1.9 tdi :-) (about 225 thousand miles, and now 40 thousand on our 2.0 NOX emitting 2010 Sportwagon)

Why did you have to replace the return line on the Injector?

The 2.5 is a v6 correct? I know on the 1.9 (inline 4) there was one primary Injector, number 3 if I remember correctly, and when you were doing anything Injector related you had to make sure to either start or end with that one.... It was bigger than the other injectors, does the 2.5 have the same type of set up?

If the Injectors aren't getting fuel you can try going back to the outlets on the back of the fuel pump, the hard lines that go to the Injectors should all connect to a typically aluminum block, loosen one and crank the engine and see if you are getting fuel there, if so then the fuel lines are just empty and are just taking longer to fill and will just need to be bled, yes each one (I had to do this once and it seemed to take forever to get fuel to all 4 injectors) If your not getting fuel there go back to the next item, maybe fuel filter, is it full? In not try filling it with fuel or a good fuel additive and try again. Keep doing this untill you find the place where you are getting fuel then you know what component isn't getting fuel.

Bill

Kevin Howe

Thanks for your reply.
Firstly all the injectors are the same size/type. I have now checked the the fuel pump solenoid and it clicks and there is a signal between the contacts . Its also clicking on when in the car, i can feel it and hear it. The fuel filter is full as is the line to the injector block.

Still no buzzing though from the fuel pump, any ideas how i check this? I've ordered a VAG diag tool so hopefully this will give me some answers. I'll let you know.
Thanks in the meantime
Kevin

bilbo6209

Do you have hard fuel lines that come out of the back of the fuel pump? If so crack one loose and crank over the engine and see if you get fuel there. If so I'm guessing you just lost the seal on the injectors when you changed the return line and they just need to be fully bleed. I had this happen when I rebuilt my head on my old 1.9T and it took a while (a lot longer than you would think) to get fuel back to each injector after the lines lost pressure, you have to remember that at idle you are injecting pico liters of fuel so it will take potentially hundreds of cranks if not more to suck all the air out of each line. I know I was told you HAD to do the injectors one at a time, crack the line at the injector, wrap it in a paper towel to prevent spray, crank it till the towel shows fuel, tighten the nut, move on to the next injector... if I remember on my 4 cylinder I had to charge my battery at least 2 times to get through all 4.

you might also want to check on fred's tdi club forums.tdiclub.com, the guys on there are going to tend to be much more tuned into diesels than the guys on this forum, we can help with general car stuff, but when it comes to diesels there are very few diesel guys on here so you wont see a lot of help here for diesel tech issues.

Bill

Kevin Howe

Cheers Bill