So... on sunday whilst going to pick up a nurse for my "i am looking for an excuse to bimble around in the landrover in the snow" moment, my in tank fuel pump shat itself. - cue me replacing a fuel pump at 10pm, on the side of the road, whilst it was snowing and -6.. joy..

bear in mind that there was no egregious noises coming from the tank or whining prior to this (it did seem a little down on power before it failed and immediately before it packed up it was horrific from what i can only assume was that it was using up the residual pressure before borking it and cutting out.


anyway... Would this likely be the cause of my poor fuel economy if it was on the way out? i have read, and had conflicting conversations about it negatively affecting economy
(i could maybe squeeze 500miles out of a full brimmed tank of diesel if i drove it like a saint on a long run which obviously isnt that good)

What do you define as 'poor' fuel economy?

I'm getting low 20's in mine and everything is working as it should. I had a failed MAF (which is claimed to cause fluctuations in MPG) but replacing it didn't really make any difference. I'm running some off road tyres as the truck spends most of it's time in fields which also drag the economy down. Again, also depends on factors such as auto/manual and what type of driving you do. My previous Defender 110 TD5 would do between 25-30 mpg's but with same driving disco won't do that. Knowing quite a few people with standard TD5's we all seem to get variations between 20 and 30 mpg.

Toseland said:

Would this likely be the cause of my poor fuel economy if it was on the way out?

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IMO not a chance

changing he maf with an original delphi unit did do some for the smoothness, and also sorted a strange hot starting "limp mode" issue which cleared shortly after. (possibly IAT related as it only did it when the engine was hot)

turned out the poor economy were the rear brakes dragging, one sides carrier had become slightly pitted and meant the pad could not retract properly and it wasnt releasing the disc.. cue hot breaks, smells and 15mpg.. back to better now,

Toseland said:

....changing he maf with an original delphi unit....

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If it's delphi it's aftermarket, the only 100% reliable one is Genuine LR made by Siemens/VDO ... which is not the same with the OEM Siemens VDO

dunno why i wrote Original, was meant to be OEM.. i think my mind was still shocked at the cost of the ambient pressure sensor in the air box..

OEM is the same manufacturer like the Genuine LR so also Siemens... any other make is aftermarket .... as for the airbox sensor if it's the old type with 3 wires is friggin expensive but you can addapt a 4 wire one which is much cheaper, a proper 4 entry plug is needed and the wires to be connected only to the pressure input

I wouldn't consider 500 miles out of a tank as "not good"?