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TD5 external fuel pump alternative


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You don't need a 2 stage pump. The Bosch pump I use for my V8 is suitable for a TD5. It also simplifies the fuel filter and pipework arrangement as you haven't got fuel going to and from the tank for the 2 stage version. You can either pull fuel through one of the existing pumps or change the pump unit for a simpler (cheaper) one. I can't remember which variety it is but there is a "pump" unit that's actually just a sender and a pickup pipe with no pump.

I can get the part number for the Bosch pump off my spare as I don't have it to hand at the moment.

I'm going this route myself at the moment with a TD5 for expedition use as the last thing I want to do is drop the fuel tank in the middle of nowhere or carry a bulky spare in tank pump. It will also mean that the spare pump can be plumbed in next to the normal one with a couple of isolator valves used to switch from one to the other.

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Thanks a lot for the info Dave, It makes me feel better on improving existing system.I'd be glad if you can tell me what you are thinking for the TD5 you mention. Here is not just a problem of price, but also is a pain trying to find a spare (right now there is only 1 fuel pump in Colombia, and the cost is, believe it or not, 3300 britain pounds).... as I see, right now I have 2 options:

1. Use the old pump (it's sending 35 PSI instead of the minimal 58 it's supposed to send), only aplying a new pump in the same line the HP stage is. However, I'm concerned in what happens if there is a mortal problem with the old one, dying both LP and HP stages.... does this means the car will be shutted off? does the new pump will be up to the work of both stages? how about the filtration work?

2. Create a new scheme:

- A new HP pump to obtain the fuel direct from the tank, adding a new filter and changing the existing one for a simpler (2 way) one. This will avoid the use of LP for filtering purposes. Using the 2 filters will also help in final pressure control (the universal pump I'm thinking can generate 9 bar of pressure, almost 30% over the original)

- The return pipe coming from the fuel cooler will be redirected to the tank.

Problems with this scheme are the air in the system (how can it be taken off?) and the ECM control (I think it's just a matter of redirect the original cables to the new pump)

In any case, the original pump will be placed in the tank for sender gauge stuff...

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The pump I'm going to use is a Bosch 0 580 254 910 as that's the pump I use on my V8 and it's done the job admirably - it also means I can buy a pump as a spare for either vehicle.

I'll be using it in the same configuration as my petrol V8, a pre-filter between the pump and the tank and a normal filter after the pump with the engine's regulator return going back to the tank.

I would try and get hold of the replacement sender unit for your tank, if nothing else you should then be able to sell your original in tank pump on and more than cover the cost of conversion by the sounds of it ! I think Off Road Toad is correct in his post above, it makes sense that the sender unit i'm thinking of is a ROW spec 300TDi unit. I'm not sure how advisable it would be to try and use an external pump to pull fuel through the existing LP pump but it may work OK.

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Ok, I think I'm getting the landscape here with the inline pump, believe yor filter scheme is simpler and more efective. Does this pre-filter means a normal unit like the one at the end of these lines? where are you thinking the best place for the new pump is? what distance between it and the filters? The Bosch you mention gives 100 L/h, kind of far from the 180 L/h the original specs, could it be a problem? what about a pump with 9 bars?

Offroad Toad, I don't understand the concept of pick up, you mean it's like my Series "pump"? how it works? what type of pressure it generates? TDi spares here are so rares as TD5 ones. When you mention the Puma you mean it doesn't use a HP pump? Thanks in advance.

Fuel-Filter-GF61-.jpg

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There are specialist pre-filters available which I'd choose over the one you linked although I can't really see any reason that wouldn't be OK as a pre-filter. I'd keep the fuel cooler inline with the regulator return just as it is now and take it's output direct to the tank return. Potentially you could also use the existing filter and it's water sensor/drain in the return line by connecting the LP input and output of the filter together BUT you cannot rely on it as a fuel filter as, without the LP stage, you need to supply a filter before and after the high pressure pump.

I wouldn't worry too much about the flow rate, that pump feeds my 5.7 litre V8 engine at 6000 rpm without any problem, pretty sure it will cope with the demands of a 2.5 litre 5 cylinder diesel :) I'm not sure how tolerant the regulator would be of too high a pressure, it might be possible that too high a pressure would overwhelm it and result in too high a fuel rail pressure... on the other hand it may cope with it without any problem.

The ECM doesn't control the fuel pump as such on a TD5, all it does is activate a relay to supply power to the pump. You just need to power the new pump from the same circuit the existing one is powered from (purple/white wire at the existing pump) with the other side of the pump connected to ground.

You shouldn't need to purge air from the new system, it will self prime through to the existing regulator. Priming the fuel rail itself if you were to run out of fuel would be the same as you would do now using the 90%+ throttle technique to tell the ECM to purge the fuel rail.

Can you get parts from the US reasonably easily ? The Bosch units (including pre and post filters) are easily available there.

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The pick-up pump is called a pump by land rover but it isn'[t actually a pump. It is just a pick up tube with a fuel gauge sender attached to it. Puma land rovers and ROW spec 300 tdi's use the same fuel tank as td5's but they don't have an in tank pump. You would need one of these if you have an external pump because i don't believe you can use the td5 one due to various valves and stuff inside them.

Heres one that sold on ebay a while back

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=150490015298

And heres the part number

WQB100440

Hope this helps you.

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I'm calling to Bogotá in the afternoon to Bosch Colombia and see if they have some pump that can do the work.

What if instead of this pick up unit I use a simple hose to obtain the fuel from the tank? I think I can use the top portion of the TD5 pump only as a housing to be able to direct the hoses into the tank, taking away the valves and stuff that can block the flow.....

I'm really thankful with your help and comments, now I feel I'm in a project, not just an idea....

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New question:

What reference of fuel filter do you reccomend to replace the original one? please have in mind new pressure going to the filter is at least 7 bar, not 0.7 bar.

Circuit will be: Bosch pump taking fuel directly from the tank using the TD5 fuel pump case, going to a line filter (the one used by Ford in his V8 5.4 Triton) and then the fuel goes to the filter I'm asking for. Somebody knows the micron's specs for the WK730/2x (TD5 OEM)?

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