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Discovery 2 Killing Fuel Pumps - Cause?


plasticbadger

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I've had on going low power issues with my D2 Td5 and a few weeks ago replaced the fuel pump. The car ran loads better with much improved power and drivability. However, within 2 weeks / 800 miles it was worse than before! The fuel pump was a cheap one and after a week I took it out due to a miss reading fuel gauge. There was already some dirt in the filters. I'm getting another new pump this week and will also replace the main filter.

Any possible reason for the truck killing the pumps, other than maybe dirty fuel? I may also clean out the tank when I change it again.

The only other issue I have is that the truck struggles to start in the mornings. My glow plugs died and seized into the head long ago though... I have changed the injector seals.

Any thoughts?

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Fuel presure regulator

Had peiblens with mine once fuel up to pressure shuts pump down supposed to then lick back in when pressure drops

Mine started giving pump failure type sympttons before eventually only running one cydle up to pressure

It worked fine when doing the bleed process

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The misreading fuel gauge could be down to a poor earth connection to the pump itself. I had all the poor performance problems and misreading gauge as the pump was finding its earth through the fuel level sender. The pump replaced, and everything went back to normal.

Also worth mentioning that at the time my FPR was leaking and had been for months and continued to leak for months after as well. Never made a bit of difference to performance and never goosed the starter.

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The trouble with cheap parts is that the first failure could be age or some normal ish failure and the second one unrelated and due to poor parts?

Until you try the new one or perform tests on the wiring you won't really know.

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You need to do cause-analysis. What caused the first pump to fail? Was *that* problem fixed before the second pump was fitted?

A leaky FPR is by itself not likely to cause a fuel-pump to fail. What's far more likely to cause pump-failure is a clogged fuel-filter and/or failed injector copper-seals.

If the injector seals fail, combustion-gases and soot get back into the fuel-system: over time this can result in a buildup of carbony slimy 'clag' in the fuel tank which can block the pick-up pipe strainer and the fuel-filter itself - with these obstructed the pump has to work harder to pump fuel (causing more heat) and it's also no longer itself being cooled by the circulating fuel - so it dies.

Fitting a new pump - well, unless you fix the underlying cause *and* steam the remaining crud from the fuel-tank, the new pump is likely to have a short and unhappy life.

If the vehicle's ever been run on Biodiesel you may also have "Diesel Fungus" in the tank and blocking the associated pipework.

I've also seen one TD5 where a cracked/porous cylinder-head allowed coolant into the 'return' side of the Diesel system. Antifreeze and Diesel mixed together produce a disturbingly-animal-looking pinky gelatinous mass.

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As I mentioned in my first post I have changed the injector seals. There's signs of dirt in the tank and the original pump filters were dirty but not blocked.

The fuel pump runs for ages before it switches off and it always struggles to start in the mornings, so I have air getting in somewhere. The power is very low, it's slower than our Tdi. There's no change to engine oil, or coolant to suggest a fuel injector seal issue again. It done just over 205k and its on the original FPR. I've also changed the MAF, air filter, turbo boost controller, injector loom and cleaned the ECU and engine loom connections.

I've now purchased a new FPR and a new pump, but I'm struggling getting a matching FPR and gasket. It seems there's three gaskets but only 2 types of FPR.

I'll report back next week when I have the new parts fitted.

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When my td5 had poor starting and running issues I eventually (after changing injector seals umpteen times and fuel pump etc etc etc) I took the head off and found it was cracked at the injector seats. This allows combustion gas to be forced into the fuel rail giving you "air" in the system and black/ dirty looking diesel. There was no effect on the cooling system or diesel mixing with oil. Steve

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When you remove the fuel pressure regulator there is a filter in the cylinder head. It is underneath a black o ring. Very well disguised. That can get blocked and cause problems.

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