Thread: Disco Td5 new fuel pump

Originally Posted by sierrafery

Actually IMO it's quite smart cos if only the HP fails the engine will still run powerless but constant on LP untill you get home, i've seen cases when even with completely failed pump the car was driveable on EUI's suction but this involves a 100% leakless system
Td5 fuel pump.jpg

Ok, so its just the one pump with 2 stages controlled by the ECU. Seems like this must be contributing to the high failure rate in some way because VDO make some pretty decent stuff. What isn't so smart is not having a carpet cutout for the frequent servicing that seems to be required. It seems that no matter what the brand, engineers get it wrong quite often. I have a bit of a background with Benz diesel models and they did some pretty dumb things, quite often as well. There are some things we just have to learn to live with.

PS. The old Merc pump diesels (pre common rail era) could easily get you down the road at 180km/hr with a failed fuel pump

Originally Posted by oztayls

Ok, so its just the one pump with 2 stages controlled by the ECU. Seems like this must be contributing to the high failure rate in some way because VDO make some pretty decent stuff. What isn't so smart is not having a carpet cutout for the frequent servicing that seems to be required. It seems that no matter what the brand, engineers get it wrong quite often. I have a bit of a background with Benz diesel models and they did some pretty dumb things, quite often as well. There are some things we just have to learn to live with.

PS. The old Merc pump diesels (pre common rail era) could easily get you down the road at 180km/hr with a failed fuel pump

For me one pump in 475,000k's is an acceptable failure rate!

Mine at 300K Km is also the original but i rarely let the tank to get close to empty, IMO keeping the tank always above quarter or as full as possible will prolonge the pump's life, all my friends who have seen too often the gauge's light had pump failures, it's not good for the pump to circulate the 70+*C hot fuel which returns from the engine so if it's more fuel in the tank the hot returned fuel will mix with it and cool down, that's why the engine runs better too after the tank was filled.

I would also think that if someone lets the injectors leak through the copper washers for a while , then the inlet filter gets blocked by black "snot" and the increased flow resistance would also be a cause of failure.

Regards Philip A

I totally agree with keeping the tank topped up as much as possible. The more air in there, the more moisture that condenses and sits at the bottom of the tank to breed bacteria to clog up the pump and fuel filter. I've had to drop quite a few tanks in my time to clean them out thoroughly, especially when I was running wvo 2-tank systems. A regular dose of bacteriacide can help mitigate what some call "diesel bug", but it's just common waterborne bacteria that's to blame. However, if you haven't treated your tank in a long time, hitting it with a bactericide can cause the bacterial colony to die suddenly, and it then detaches from the tank surfaces to suddenly find its way to the pump and filter system to leave you stranded.

Best practice is to drop the tank, clean it out thoroughly and then keep dosing regularly after that.

Also, if your car lives outside, the tank is subjected to more temperature fluctuations, so condensation is worse...