Intermittent starting problems

[mrandyt]

This has really stumped me! Went out the other day in the car parked up then came back to start it, the engine turned over (didn't start) for about 5 seconds then stopped I kept trying for about 15 minutes and no joy and not even a engine light or warning light on the dash, I called out the aa and he tried it and it started! And followed me home to look at the ecu to which there was no faults, this has been happening since Saturday where it will sometimes start and other times not? The car seems to run fine but it has had a few splutters since Saturday but it's not cutting out.
Any of you guys know what this could be? Maybe crank position sensor? As I said there are no engine management lights on and don't go into limp mode.
Car is a a4 2.0 tdi b7

 

[SootySport]

That sounds like a very basic fault like 12v. or earth connection not getting to the ecu. Unless you have it scanned it's going to be a tricky one to find if it is intermittent.

 

[SootySport]

Another idea-------Water in the fuel system won't show up any faults.

 

[mrandyt]

Another idea-------Water in the fuel system won't show up any faults.

The rac thought the cam belt had snapped because of the sound of the engine but it obviously wasn't, it will keep turning over for only a few seconds and not start and the starter will stop cranking

 

[Tfsi gone]

Fuel filter ok? Maybe fuel pump. Battery within 3 yrs of age, connections? Lots to check. Start with the first mate..

 

[mrandyt]

Ah yeah could be fuel pump/filter ! Any idea where this is located on a 2.0 tdi 170 2006

 

[SootySport]

Fuel pump is inside he tank, you should hear it running as soon as turn on the ignition. Unlikely to be that though as this would show up a fault code.

 

[madstaff]

Low on fuel and parked nose up??

 

[mrandyt]

Fuel is always above or on the half way mark, booked the car in tomorrow for a oil change so having the fuel filter changed while it's there, any other ideas what it could be

 

[disk0]

Does the coil light display on the dash when you insert the key to start up? Reason I ask is I had a problem with the fuel pump relay on mine

 

[mrandyt]

Yes it does light up but it always has, had the fuel filter changed to today so I'll see how it goes tomorrow