Swirl flaps and low fuel pressure - related ? 3.0 TDI

[a5qtro]

Hi,

Wondering if anybody can help me here. Had my A5 3.0 TDI Quattro a while now and I am still chasing a common low fuel pressure fault that has been appearing from time to time. Typically a flashing glow plug light appears, and usually goes by the next time you start the car up. A scan with VCDS always shows 5215 - Fuel Rail/System Pressure P0087 00 [096] - Too Low.

A month or so ago, this happened again, but this time the car would stall pretty much immediately after starting. Another scan showed the same low fuel pressure error, but also an error pointing to the fuel pressure sensor 5244 - Fuel Pressure Sensor (G247) P0193 00 [032] - Short to Plus. So i took a stab at replacing this sensor with a new unit from Audi. This has made little to no difference.

Anyhow the symptoms have over the last few weeks remained, the same low fuel pressure being thrown every now and then, but always at random intervals. I have noticed the car running rather rough too, and the idle has always been quite erratic. If you graph the requested fuel pressure and actual fuel pressure in VCDS, it is all over the place.

A few days ago I got in the car after work after it running as it normally does, and it took an extended amount of time to crank over before starting. I drove home perfectly fine and parked up. The next day when I started the car, the MIL light was on (not the glow plug one, the main engine light). So I scanned the car for codes again and this time I have the following:-

7156 - Intake Manifold Flap Position Sensor (Bank 1) P2015 00 [032] - Implausible Signal

Now I am aware that these flaps are problematic, and I am aware that my car has this issue. While washing our cars over the weekend I had a friend look under the bonnet at the actuator arms whilst I started the car, bank 2 was fine but bank 1 absolutely no movement. I gave the arm a little tug with a long nosed pliers and it moved up and is now moving ok. So when the car is revved, both arms are moving fine now, although bank 1 does seem to be very loose at the bottom.

I will fit the repair kit for the arms when I get time as this is quite obviously a problem.

However on to the ACTUAL question...

Does anybody know, if my bank 1 actuator was stuck in the down position (not sure if this means flaps open or flaps closed) could this on some occasions cause the engine to think that the fuel pressure was too low ? Or could anything to do with these flaps cause the engine to not command the ECU to supply more fuel or something along them lines. Or in simpler terms could my stuck swirl flaps cause my low fuel pressure issue or is there absolutely no way on earth that these two issues could be related ?

It's worth mentioning that after unsticking the bank 1 actuator the car is running much better than it was previously. A lot smoother and much more willing to pull and rev and the revs don't seem to "hunt" any more at idle either.

Any help would be greatly appreciated.

Thanks,
Al.

[rowdy-999]

Have you tried resetting the codes, driving the car for a while and re scanning for the fuel codes?

[Alan02]

The fuel pressure fault code may be produced by a faulty fuel pressure regulator.