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Old 8th June 2022, 17:35   #1
MissMoppet
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Default Broke down, again

A week after breaking down in Galloway - and the RAC sold me a new battery - it happened again, but this time just six miles from home. This time it was the UB Pump that I'd changed just 15K miles ago. Surely should last longer than that? (Bought from DMGRS described as "OEM -Q, WQB100481").


Fortunately the chap found me a local factor who had one and fitted it. Intermotor at cost of £129. Could it have failed because the In-Tank pump is failing and put an extra load on this?
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Old 8th June 2022, 21:26   #2
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Quote:
Originally Posted by MissMoppet View Post
A week after breaking down in Galloway - and the RAC sold me a new battery - it happened again, but this time just six miles from home. This time it was the UB Pump that I'd changed just 15K miles ago. Surely should last longer than that? (Bought from DMGRS described as "OEM -Q, WQB100481").


Fortunately the chap found me a local factor who had one and fitted it. Intermotor at cost of £129. Could it have failed because the In-Tank pump is failing and put an extra load on this?
Sorry to hear you've broken down again.
Hopefully the Intermotor one will be ok, when you're broken down and need to get it up and running you take what you can get.
But generally the only ones I recommend are either the Pierburg or Ti pumps that were fitted as standard. Both should last over 100k miles.
The in-tank pump on a two pump system is just to transfer fuel from one side of the tank to the other.
The reason why with a failed in-tank pump the car cuts out under 1/4 tank is that it empties the side of the tank with the fuel pick up

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Old 8th June 2022, 23:14   #3
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The in tank pump does a bit more than that Russ - they fit them to the Freelander TD4 and that doesn't have a saddle tank.

I've never looked inside the fuel tank after running out of fuel with a failed ITP, but I have bench tested both pumps, and the the reason the UBP sucks air at around a quarter of a tank level is due to the priming valve on top of the ITP becoming exposed, and looking at how high up in the tank the top of the ITP sits, that would be at around a quarter of a tank's worth of fuel. There are two valves on top of the ITP, one spring loaded for pressure relief, and the priming valve which is a floating ball that shuts as diesel is pumped up into the LP circuit, so with a failed ITP it remains open.

ITP's do assist with fuel pressure in the LP circuit, and also with self priming if the car runs out of fuel. Probably not a problem for us here in the UK, but in the middle of an Alaskan winter, it may be more of a benefit.











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Old 9th June 2022, 11:49   #4
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Yes Mike the in-tank pump will supply some fuel but not at any significant pressure, certainly not enough to run the car.
The Freelander although it uses a flat tank just utilises the same fuel delivery system as the early 75. The ECU's were set up for two pumps so that what they got.

I've looked into the tank on both sides with early cars that have a failed in-tank pump and there's quite a difference.

The interior tank pipework is totally different in the later models with a single pump so the problem with differences in tank level can't arise. You can't change over a early car to single pump without changing the tank and the pipework

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Old 10th June 2022, 08:49   #5
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Yes I wasn't implying the car will run on just the ITP, but that the system was designed to run at a set pressure, and the ITP contributes to it -no doubt you'd have seen the difference looking at the LP fuel pressures from cars with running and failed ITPs.

If Rover fitted a redundant pump to the Freelander then they missed a trick - Henry Ford was quoted as replying when asked why he didn't fit a fuel pump to his Model T that fuel pumps were a dollar a piece and he produced 15 million cars so the questioner could work out the answer. They only made around 540000 Freelander 1's, but fuel pumps cost a fair bit more than a dollar a piece these days. Can't see it making any difference to the ECU how many pumps are fitted as they both go through the one relay.

I'm probably in a very small minority on here but I think the fuel system for the diesels was very well designed. We don't get problems with condensation or priming, and just about the only weakness is the combination of materials for the ITP commutators and brushes - the ones I've stripped down have worn out commutators and brushes as good as new.

The vast majority of the problems on the forum come after ITPs are replaced and not fitted correctly, the pipework not clipped back in, the module seals either fitted the wrong way round or in the wrong order etc - but the one thing they have in common is that they all self inflicted and not the fault of the car.

Shame we can't talk to the designers to see exactly why they designed what they did but it's all good fun kicking it around on here!
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Old 10th June 2022, 12:08   #6
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Default DMGRS pump under warranty

Fortunately Mat at DMGRS has said the pump is still under warranty, but he agrees with me that such early failure could be the consequence of a failing I-Tank Pump. I can't hear any hum from the rear seat when starting (key pos 2) so presumably the obvious way of testing is to disconnect the fuel line in front of the in-line fuel filter, and try to start it?
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Old 10th June 2022, 18:04   #7
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Better to unplug the UBP, turn the key to position II and with your ear next to the open fuel filler pipe listen for a faint whirring.

I don't know about aftermarket pumps, but with the factory fit UBPs a failed ITP won't cause the UPB to fail. Bit of an old wives tail that one.
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Old 10th June 2022, 19:18   #8
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Quote:
Originally Posted by Mike Noc View Post
Better to unplug the UBP, turn the key to position II and with your ear next to the open fuel filler pipe listen for a faint whirring.

I don't know about aftermarket pumps, but with the factory fit UBPs a failed ITP won't cause the UPB to fail. Bit of an old wives tail that one.
Thanks but my old woman has yet to grow one.
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