TD5 fuel pump queries

Evening all

Removed the tank and fuel pump on my td5 90 today. Hoping to find it was fitted with a cheap aftermarket unit as the previous owner had gained access to the in Tank pump before. Vehicle has done 95k, does this look like it has been replaced before? It states VDO England, but no age markings.



The reason for inspecting, is because when the car is left, it's obvious there is air in the fuel system. It's very obvious when the key is turned. Cranks for ages too, and then misses and fires. Seems to run fine after.

I've been doing a slight restoration on it. So hasn't been driven in that time its had FPR rebuilt, new valves in filter housing. But filter housing had been replaced by previous owner. And genuine LR injector washers and seals.

Any ideas please? Really dont want to fork out for a new pump if it's a waste of time

You seem to have followed up on some of the main suspects, and the story is one of the common problems faced by TD5 owners, the injector seals can fail and cause gas to pass into the fuel rail in the head, which causes the fuel pump to whine when the ignition is on.
To test the pump you could take out the fuel temperature sensor from the FPR and connect a pressure gauge using a flexible pipe, if it holds 4 bars pressure when the engine is running loaded then the pump is probably OK.
I think many fuel pumps get changed by people who then find that was not the problem.
Throwing parts at it is costly and frustrating.

raywin said:

You seem to have followed up on some of the main suspects, and the story is one of the common problems faced by TD5 owners, the injector seals can fail and cause gas to pass into the fuel rail in the head, which causes the fuel pump to whine when the ignition is on.
To test the pump you could take out the fuel temperature sensor from the FPR and connect a pressure gauge using a flexible pipe, if it holds 4 bars pressure when the engine is running loaded then the pump is probably OK.
I think many fuel pumps get changed by people who then find that was not the problem.
Throwing parts at it is costly and frustrating.

Click to expand...

Thanks mate. I was going to put a pressure tester on the FPR, but I thought with my little knowledge that it may show a good reading whether it be air or diesel?

So I was hoping to see a cheap Chinese fuel pump, but seeing as its VDO, I'm wondering if it's the original or a recent replacement. Although I think VDO is Germany of recent years and not UK, like it says on it meaning it could be the original.

The pressure gauge will show the pressure in the fuel line if its fuel air or a mix, but the thing is if it holds at 4 bar when loaded then you can take the pump and FPR off your list and search elsewhere.
I had similar problems and its frustrating many people get locked into changing parts but this shotgun approach is expensive, some parts are quite cheap and worth doing anyway, but pumps are a bit more expensive and it must be sickening to charge it and find that's not the problem.
I took off my fuel filter head cleaned it and replaced the copper washers on the connections and that seemed to help, but it can be connectors on the pipes or very often the copper washers on the injectors which let gas into the fuel line in the head.

I'm interested in the colour of the fuel pump. I've taken a few out in my time but I don't think I've seen one as dirty as that. There's a lot of dark brown deposits. It looks like someone has been running the car on old sump oil. In which case that may be part of the problem. Alternatively it may be that some of the rubber components such as seals and hoses have been deteriorating and getting in the fuel. A bit like clutch fluid going black when the seals are dissolving.

Brown said:

I'm interested in the colour of the fuel pump. I've taken a few out in my time but I don't think I've seen one as dirty as that. There's a lot of dark brown deposits. It looks like someone has been running the car on old sump oil. In which case that may be part of the problem. Alternatively it may be that some of the rubber components such as seals and hoses have been deteriorating and getting in the fuel. A bit like clutch fluid going black when the seals are dissolving.

Click to expand...

I would agree, seems a lot dirtier than my old TD5 pump when that was removed. Mine also appeared to be original VDO unit, replaced with a cheap Bearmach version, luckily it was the pump that had gone in mine. Pig of a job on the 90!

Thanks chaps. Apparently the black build up is engine oil and carbon from the injector washers failing.

Anyhow, stripped and cleaned the fuel pump today. The internal gauze filter was clean, despite the external mesh being very dirty. Unfortunately, I'm very reluctant to buy a new one at the moment. I'm starting to second guess the replacement I did of the injector seals and washers. Even though I made sure the seats were spotless, as were the injectors.