Td5 power surge and power loss

Hi all. Just found this site, thanks to all that have already indirectly helped with my problem. Whilst under hard acceleration the other day the engine started to cut in and out at 2.5 3k revs, followed then by a less violent presence of the cutting in and out, but with a verying max of revs of 3k to 4.1k. On route home i tried a new fuel filter, with the same sympton present i started to look on the internet. Having found the usual thread on injector harness i found oil at the rocker cover and ecu plug. I then cleaned out the ecu plug and fitted a new harness, fault still the same, I then following advise checked inside the ecu for oil, none, found. Under more investigation i found the air filter had sucked in, changed and no difference again. At this point i took the vehicle to an independant LR specialist, who cleared the faults on the ecu and took the vehicle for a test run. The ecu still then showed no faults. We then looked at the intercooler for obvious stone damage etc and none found. Again following surgestion we changed the fuel pump in the tank and found no difference, so refitted the old one. We then inspected the waste gate tube work for cracks etc and tested the waste gate operation. This seemed to be a little sticky, so we worked it and lubed but now with smooth movment it still has the same fault. The lr has not got aircon so the wiring loom has not rubbed through either. The next surgestion is to change the fuel filter assemberly, but at £80 i dont really want to keep buying bits untill i find the offending item. Can any body help, I am rapidly running out of ideas.
If it helps its done 150k

It is overboosting - simple as that,the wastegate lever must be totally sloppy in operation to work quick enough.The other fault I have seen when the arm is free to move is that the compressor housing is slightly out of alignment and causes the boost control rod to pull at a slight angle on the arm, making it jam.Fixed by slackening the 6 fastners around the turbo and straightening it up.
On a live data display with Testbook the boost MUST NOT go over 225kpa or the ECU will cut fuelling make it do the kangaroo bit.Max boost can happen as low as 2100rpm so the wastegate is working alot of the time.

eightinavee said:

It is overboosting - simple as that,the wastegate lever must be totally sloppy in operation to work quick enough.The other fault I have seen when the arm is free to move is that the compressor housing is slightly out of alignment and causes the boost control rod to pull at a slight angle on the arm, making it jam.Fixed by slackening the 6 fastners around the turbo and straightening it up.
On a live data display with Testbook the boost MUST NOT go over 225kpa or the ECU will cut fuelling make it do the kangaroo bit.Max boost can happen as low as 2100rpm so the wastegate is working alot of the time.

Click to expand...

Wow .... when you say 225 KPA max, that's over two BAR, 32 psi so is that an 'absolute' pressure including atmospheric?

I have a boost gauge on my TD5 Disco and it never exceeds about 1.0 BAR.

I would LOVE to get that doubled but not if it's inviting grief.

CHarlesY

Remember 100 kpa is atmospheric pressure,225 is what they get up to - Defender and Disco.So the boost pressure is only 125 kpa max above atmospheric.

Thanks for that, i will look again at the waste gate and get a pressure guage.
James