2.5 TDI Fails to start

[GMIBMan]

Hi there everyone, I'm new to this forum as I've usually been pretty self-sufficient when it comes to working on the car. But this problem is a real beauty and I'm pulling my hair out to try and resolve the issue. It all started when my wife broken down in the car last week. She told me that the coil light flashed a couple of times and then the car just died!!! AA man was called...spent an hour and a half on the car but could not get it to fire up. He could not find any TFC's but went systematically through the basics to try and get an idea for what was going on. In the end he towed the car and it's now in the garage. I checked for TFC's and found 01441. Which indicated a fuel level sender -G210- Implausible signal. This message is stored if the sender for low fuel level indicates "no fuel" but the fuel level signal in the dash states otherwise! The symptoms for the above fault match and it states to check the Fuel Pump, check that the baffle housing is filled and bleed the fuel system. I went straight off and check the pump electrically and sure enough it was audible (but there was a load of air in the system that could be plainly heard whilst the pump was working. The car fuel gauge was just above reserve so I thought I'd add a bit more diesel in it. So I added 10 litres just to make sure. I then bled the fuel system as per ELSA and got loads of air out of the system. But the car still fails to start!!! I then checked the low level fuel sender G210 and found that it only showed 100ohms on the meter. Which basically states that the baffle housing is not filling up. I opened up the two compartments and visually checked and sure enough the housing is bone dry!!! I've looked at the pipework and can't see anything wrong and the pump is spinning so I'm really up that creek without a paddle at the moment. Can anybody shed any light on the problem for me. I really appreciate it!!!! Cheers GMIBMan

[GMIBMan]

I have spent at least another 10 hours on this one trying to find the route cause.
I finally purged all the hoses and checked the connectors in the tank that connect the following together:
Baffle Housing
Fuel Pump
Suction Pump - left & right hand side
Fuel return to baffle housing
I blew them all through with compressed air to make sure that there were no blockages.
Then I run up the pump on it's own by powering up fuse 28 from the battery.
I noticed that not a lot was happening and the pump was virtually running dry.
I then primed the baffle housing with diesel and an almighty gurgle came from the left hand side of the tank. All of a sudden the chamber was filling and loads of air was being pushed out into the housing.
I put everything back together again and tried the car. It eventually worked after about 14seconds of cranking on the key.
It has been fine ever since!!!

It must have picked up some crud from the bottom of the tank which prevented the suction from working properly!!!!

I hope it doesn't happen to you guys.

[Jusforfun]

Interesting thread. A few of the Q7 guys have had similar issues with gauge reading above reserve yet running out. Its not specifically a TDI thing. In a couple of cases the cars have been in service for days (maybe waiting for parts). The latest case is at this time unresolved despite all components including gauge being replaced.
It appears the display reading can be shifted via VAG Com.
Have you tried running into the red since?

[GMIBMan]

Thanks for data on this one. I have run the car down to reserve since and it was fine. So I guess the problem was with the suction pump losing pressure due to crud in the pickup from the other side of the tank.

[sergiu_blue19]

Hi guys ,i have the same problem with my audi a6 2.5 tdi 2003.The car had been of the road for about 3 months due to injection pump failure,after replacing the injection pump and coding the glow plug light was flashing...pulled out the same code g210 low level fuel sender,got a replacement from audi but that didn't solved i have the same code and the light still flashig in dashboard....Now i just seen your post there and i don't know witch is the baffle housing,is that the plastic housing around the lift pump in the tank?

[GMIBMan]

Originally Posted by sergiu_blue19

Hi guys ,i have the same problem with my audi a6 2.5 tdi 2003.The car had been of the road for about 3 months due to injection pump failure,after replacing the injection pump and coding the glow plug light was flashing...pulled out the same code g210 low level fuel sender,got a replacement from audi but that didn't solved i have the same code and the light still flashig in dashboard....Now i just seen your post there and i don't know witch is the baffle housing,is that the plastic housing around the lift pump in the tank?

Hi Sergiu_blue, you're absolutely correct...the baffle housing is the container that the pump sits in.
If the baffle housing is not primed (i.e. bone dry) it won't suck up the diesel from the other side.
Try doing what I did by priming the baffle and running the pump in isolation. Then see if the baffle continues to be filled under the pumps pressure.
Good luck

[sergiu_blue19]

Right,i opened the pump in the tank again and there is no pump in the tank,is just the plastic housing ,level sensor and another small sensor inside the plastic housing. The car is a 2003 a6 engine code BCZ,em i missing somthing,is there another acces to the tank other that the one in the boot? Thankyou

[GMIBMan]

OK...you're absolutely right...If I remember correctly there is a cylindrical plastic housing and the pump is contained as part of this unit.
I have an avant and the access plate is under the rear seat on the right hand side.As far as I can remember this is the only access.
Hope this helps

[sergiu_blue19]

right...totaly diffrent,there's nothing under the seat apart from the yaw sebsor ....star wondering if a wire could touch the body somwhere shorting out...