Td5 sometimes has no power

Hi everyone... an interesting problem here. On my 1999 Discovery 2 Td5 manual, in the low rev range sometimes and not all the time i find that the car has no go at all, you push the throttle down fully and nothing really happens. VERY slowly as the revs build the power will all of a sudden come and your off. There are no abnormal engine noises and it revs perfectly and has power in the mid and upper rev range but it seems if you bog it down too much it will sometimes just completely die and if your on a bit of a hill first gear almost isn't enough and you really have to rev it and boot it to get it going - can be a real pain on hill starts. When the power does come in though, it feels similar to a waste gate suddenly opening then you have all the boost pressure and power. However i doubt it to be the waste gate as the turbo is new and the waste gate is free to move (but does require a bit of force). Ive tried driving with the MAF disconnected which made no difference, and the red plug is oil free. Definitely not turbo lag though and i might add can be a bit abrupt when the power comes in. Could it be the boost modulator??

you can rule out the wastegate modulator by taking the pipe from it's bottom and connect it to the wastegate actuator valve, then it will act like on the defender...though it seems to me that the fuel pump's high pressure side it's on it's way out for you

thanks for that, ill try that and see if that makes any difference. But if the the 'high pressure side' of the fuel pump is on its way out then does that mean a fuel pump replacement in general? The fuel pump isn't really making the loud noises that indicate a td5 fuel pump failure.

usually the pump noises are generated by bad flow due to rubbish filter or air in the system and it's coming from the low pressure stage, the high pressure goes directly to the head it's not routed through the filter... the Td5 will run even on low pressure just without power... to check the HP a gauge is needed instead of the sensor in the FPR

there could be many other reasons for lack of power, live data readings with tester can reveal things, if all the sensor readings are good and no fault codes logged then it's almost sure that the problem is with fuel supply cos it's not covered by diagnostics

interesting, thanks for the info sierrafery. Im going to take the car into local landy experts relatively soon so ill get them to put all the gauges and diagnostic equipment into it and see what we find. Hopefully will be able to solve the 3 amigos at the same time.

Both my Defenders and my dad's Disco do this when started. For about 10-15 seconds, it has no power and the suddenly jumps to life as if you flicked a switch.

been having same sort of problem ,drive on low revs then accelerate no power you wait and wait then suddenly away you go change gear wait then it clears also when not doing that it would suddenly feel like a lazy throttle press down and just felt lazy. bought hawkeye and found iat sensor would go from 20 degrees to 119 this is when all power disappeared then come back when temp dropped the lazy throttle was temp showing -36 put on new map sensor never felt smoother