A6 1.9 TDI c5 2004 Won't Start Help

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Hi, I have this periodic starting problem with my A6. The fuel pump primes, the car turns over, volts are good but doesn't fire up and start. I replaced the t-bar joint for the fuel lines as that sometimes cracks and pulls air in. It was fine but 5 days later same fault?

Any ideas?
 
No codes! Which is why it's strange. Yesterday at midday I we tout to take dog for a walk and wouldn't start! Later I got it going with some easy start and drive to work. After 10 hours at work went out and started no problems?

It is very intermittent. My drive is on a slope as is the car park at work. When it's not started it's been pointing upwards! Son think I'm thinking fuel pump fault letting air in?
 
audi upgrades
No fuel level doesn't change it. It seems to start pointing downhill and flat. I have now also changed fuel filter.

But I think it must be pump or air getting in some how?

How much should a fuel pump set me back?
 
Could your tank vent not be opening properly and not allowing air in and fuel out I think that when you fit the cap it pushes a pin in the filler neck opening the tank vent.
it would start with the cap removed if this is the fault just a stab in the dark though.
 
Change the fuel filter to a quality Hengst or Bosch and replace the thermostatic tee valve at the same time- use a genuine valve or you can get cheaper Febi ones from Euro Car Parts ! It will cure your issues...
 
Adams24 - right changed both of those with genuine parts and it started after a recent failure, sitting on drive. I'm going to use on a daily basis now with a can of Easy Start just incase! Fingers crossed all will be well. The rear pump seems to be pushing enough fuel all the way to the head so hopefully this will fix it?

Another question though, you know the fuel pump on the head? Does that have a one way valve in it, so it stops fuel returning down the line? It's just I clamped the hose just after it and it churned but eventually fired up, when I was testing what it could be. This pump is a sealed unit but I was just thinking it could be faulty?
 
Ok I have replaced the fuel pump tank. But now I'm getting a different start fault. Now occasionally after about 15 seconds of turning it splutters into life and starts. Then no issues through the rest of the day, or for a few more days. Could this be injector valve seals?
 
Is your filter definitely full up? Take the pipe of the filter and turn ignition on you should get some fuel come through for a couple of seconds and then stop. Make sure this is happening as this primes the system every time. Also make sure that the tee valve has been mounted the right way, a mistake easily done (been there). If that is all good then you may have a problem with injectors
 
Tony,

Cheers the filter and tvalve was replaced by a mate, who is an Audi mechanic so I hope he has done it right. If not what am I looking for? Also reference the fuel filter, I take it that I should pull hose off engine side? Then if this is not full, what do you think the fault is? I have replaced the fuel tank pump?
 
The pipe you want to pull off is the one the that goes back to the tank and get something to catch spilt diesel. Put ignition on and a small amount of diesel should come out just for a couple of seconds and then shut off. The idea of this is to make sure the filter is topped right up before starting. If you don't have any diesel priming the filter it may explain your poor starting fault. If this is all ok has the car had a timing belt recently? Because the next thing I would look at is timing. The timing can also slip as the cam has slight adjustments on 3 13mm bolts mad these can slips if they haven't been tightened enough
 
To see if the t valve is fitted right it has a narrow for direction of flow towards the engine so the arrow should be pointing to the pipe that goes to the tandem pump on the back of the head
 
The cam is due to be changed in August. It's done 70,000 from new and had one cam change so this is its second on time not miles. I will get that done first then before valve seals and see if that fixes it. One I check your suggestions. If not then I will change the valve seals.
 
What do you mean by injector valve seals? Injector seals? It's very rare that they go and you would then have diesel in your engine oil. I wouldn't think it would be them. Maybe get your mate to check the injection timing/duration on vagcom if he has access to it
 
Ok cheers. I took it to a local Vag garage and told them the vault and asked there opinion they said they have had similar faults and said it was wear on the injector valve seals? I think I will get cam done as that's needed. And get him to do those checks as well. Thanks
 
That's fair enough. Those guys have probably got a lot more experience than me!!just I've never come across that before! Let us know what cures it in the end though!
 
I will get the car to a specialist, ńone of what your mechanics diagnosed does make sense...
 
I have just changed the cam/trimming belts and no change.

I think I will take it to Diesco, in Ipswich who are Diesel engine/injector specialists and see if they can diagnose the fault.

When I had the cam belt done at a local VAG garage they put it on the box and no fault codes! They reckon it's either leaking injector valve seals or engine fuel pump! Which would be costly. But if I take it to Diesco they should be able to recondition the pump if that's the fault!
 
I have a film clip of it not starting and will try and upload it.
 
On this clip the fuel comes through and it starts quickly, sometimes it is more spluttering before firing up!?
 
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