P38 BMW Diesel Engine problem

I have had my Range Rover for 2 years and have had the usual problems that my local independant dealer has sorted for me, heated seats, air con, fuel pump, alarm etc etc.

The trouble is something always goes wrong just when i am getting ready to sell the car. The latest problem is verry puzzling. It became apparant when overtaking a car on my way home work. I was doing about 35mph and floored the accelerator to kick down, as i am accelerating the revs hit 3500-4000 RPM and then nothing, the engine would not rev any more and would not change up. Only when i completely lifted off and then back on with the accelerator did the engine change up and i continued to accelerate.

This i thought must have been a one off, but to my disbelief it now happens most of the time (but not always) that if i floor the accelerator the engine hits a 'rev' brick wall at about 3750 RPM and makes a hissing noise. Then after lifting off and only giving about 50-70% throttle will the car continue to accelerate.

I am having horrible thoughts of injector pumps faulty or worse. I have a vann akken chip fitted but otherwise the engine is FSH on 80,000 miles and standard. A new 'in tank' fuel pump was fitted 6000 miles ago to correct a starting problem.

If anyone has had a similar experience i would apprieciate some advice.

Many thanks

possible air intake problems. check ur hoses for cracks/blockages.

Thanks Bigstoo

All hoses look to be in v,good condition. I know they can de-laminate internally but i'm not going to start stripping them just yet.

I forgot to add that the engine runs perfectly. It is only under full throttle acceleration that something happens at about 4000 RPM, it's as though the engine management shuts off the fuel supply, its that sudden. I suspect the the hissing/wheasing noise will be a turbo bypass or a relief valve operating (i'm only guessing btw).

Any suggestions would be a great help.

Thanks

hmmm i still think its an air problem. are the hoses to the turbo soft or firm?

Hi Bigstoo

Had a look at all the hoses this morning. They are all of the soft type with like a banding around them. They are very easy to squeeze so i think they are supposed to be like that.

I think you may have a good point though, it is worth removing each hose in turn from the airbox to the inlet to check for cracks, holes or splits.

I can sort of see that under full throttle that if the turbo pressure is all out of sink to the fuel injection the ecu may shut the fuel off ??

I will re-post with my findings, defo worth a look before i take it to the garage.

Thanks

Don't wish to cause alarm, but we had a VW Passat doing the same recently and it was air flow meter failure....

What happens is that the ECU goes into safe mode when one of the various sensors fails, to stop you blowing it up....

Was same symptoms too....seemed OK, then brick wall of frustration.....

Hope it helps the problem, if not the wallet

anyone reading this i had same problem. it was the hoses colapsing, disconnect hose from air filter and try again if better replace air hoses