Thread: 300 TDi Cutting out after 40 mins of driving

To Check that the alarm spider isn't to blame, run a jumper wire from the battery positive to the fuel pump solenoid, this will completely bypass the ignition and immobiliser circuits. (This means you will have to open the bonnet to shut it off) but you can at least test the theory by going for a drive for an hour and if all OK chances are that you will need the alarm spider (immobiliser) bypassed.

JC

Thanks for the advice Justin. I’ll try to give that a go tonight. Is the fuel pump solenoid the unit that sits below the pump with the connectors facing towards the driver?

Originally Posted by digahole78

Thanks for the advice Justin. I’ll try to give that a go tonight. Is the fuel pump solenoid the unit that sits below the pump with the connectors facing towards the driver?

Yes, you can trace the power wire from near the fuse block in convoluted tubing leading to the back of the injector pump. also check that the connector is tight and clean, nip it down with pliers and push back on.

you could also have a small leak on the suction side of the pump that is letting air into the system.

This isnt the case if when it starts after being left for 10 minutes it starts instantly.

The air in the fuel problem Dave mentions could be caused by one of the fuel lines rubbing through on the aircon pipes, near the brake booster. I have had a 300Tdi D1 do that. It was a tiny hole, and took a while for the engine to die off, and would start OK in the morning etc but definately got worse the more it was driven.

JC

I've seen a blocked fuel tank breather that combined with a very slight fuel line leak - caused this sort of behaviour - although that was one a V8. But perhaps it's possible on a TDI. The fuel tank develops enough of a vaccuum to eventually stop the fuel flow.

Thanks for the responses lads.

I noticed the spade connector on the fuel pump solenoid wasn’t as tight as I’d like. Not sure if that could be it or if it could still be the immobiliser spider. I’ve made up a cable to chuck in next time it conks out.

The roads out past Dolby were pretty rutted so it could have shaken some electrickery loose. I think for $20 the spider bypass fix might be worthwhile to help bulletproof her even if it’s not the problem right now.

Regarding the tank breather, i filled up during my break down saga on sunday and didn't notice any pressure release from the cap. I'll be sure to check the lines anyway.

Well, i cleaned out the sedimenter and chaged the fuel filter. I even set up a light in my dash that comes on with the fuel pump to see if i could identify an electrical problem.

But yesterday, it did it again. Only seems to be on the highway at 100kmh speeds. Drove to work the days before with no problems. Again, after 20 mins (in which time it would start straight away buy slowly die) it decided to fire back into life like nothing had happened.

Also, just noticed the 90 degree pipe from the turbo had delaminated. I'l replace it this week. Could this cause these symptoms?

Have you guys got any tips for what to concentrate on next?