2005 Octavia 2 140 Tdi 70,000 miles full sevice history and glow plugs replaced May 2011.

Every now and then with no previous indication the engine will not start on first crank. I have to keep the enging cranking over a few times before it starts ( cranking for too long brings the oil pressure light on).

There is no pattern to to this problem, the car could be stood for a day or a week when it occurs, and of course no fault shows on the diagnostics afterwards.

I think it is fuel related as the battery is in good condition but getting on a bit.

I have searched the forum but not found any other post regarding this problem but other posts refer to fuel pump relays, could it be something to do with that.

How does the enging stop? is it a fuel cut off? could that be sticking?

If I can get an idea of what the problem could be, I can then get those parts checked or replaced and see how it goes from there.

This started 18 months ago and I hoped that new glow plugs would sort it out but it refused to start yesterday for the first time since replacement.

Might be worth changing the fuel filter. I know mine had a lot of black gunge in it which was coming from bacteria growing in the tank.

I had to to put an anti biocide in the tank to clear the bacteria then change the fuel filter a few times until it cleared.

Symptons prior to this were pretty much the same as yours.

Hope that helps.

A friend of mine had the engine cut out on him several times. This was due to a black gunge in the fuel tank blocking the mesh filter on the fuel pump. He took the fuel pump out and cleaned it with turpentine. After doing this several times he cleared the fault.

I wouldn't do this myself, so use at your own risk.

He had a kia and was running on a high percentage bio-diesel.