Maxxed_Ross wrote:

well look what I found when giving the air box a good deep clean


That explains why it was getting worse

Oooo pre-filter

Do we think a prank?!

Maxxed_Ross wrote:

I'm at the end of my tether with this one, so hopefully someone can help. I've been through every "power" related thread and still can't find an answer

So the story goes:

Bought a 2001 TD5 90 just over a year ago. Was remapped by a company I've never heard of but pulls like a train. Fuel economy and torque delivery was decent so I fitted a Disco 2.1 transfer box and slightly bigger tyres. It's also running a bigger alloy intercooler.

Ran fine for a while then occasionally would loose power on the motorway. I changed the fuel filter and this seemed to solve it for a while. Since then it has been progressively getting worse to the point where it's almost impossible to drive.

The issue happens in all gears if they're held for too long, so I've gotten into the habbit of short shifting and just sitting at 60 on the motorway. All is fine until I either let the revs wander up a bit too high or I hit a hill. The engine starts the clatter, they're a huge ploom of black smoke out the back and all power is lost. I've tried keeping my foot planted but it just gets slower and slower. lifting off and accelerating again brings back normal power until it happens again.

Strange thing is that once it happens that first time it'll do it totally at random while driving. The slightest load increase by going up a hill, an increase in head wind or even over taking a lorry can trigger the power cut again. If the car is turned off fully then started again it'll cruise past trucks at 60mph without any issues at all

I've had a nanocom plugged in during a test run and the turbo pressure drops totally when this happens

Injector balance is good, MAF readings are normal and the only weird fault code it threw up once was an overspeed crank detection... but it's never shown that before or since.

The list of things I've checked / changed / swapped

- EGR fully removed and blanked, all blanks and plugs ok
- New genuine MAF 6 months ago
- New genuine crank sensor with spacer
- New genuine fuel pump
- New mahle fuel filter, no change at all this time
- Recent diesel pressure regulator with genuine gasket
- Regularly checked Terrafirma air filter
- New silicone boost hoses
- Turbo play checked and ok
- Turbo hoses all checked and ok
- Swapped actuator, no success
- Wastegate moves fine
- Actuator rod set for 13 threads (standard I believe)
- MAP sensor swapped with another working vehicle, no change
- Injector washers and loom replaced about 6 months before issues
- Minimal oil in the ECU harness
- Fitted Alive boost box, no change

I also tried swapping the ECU for a standard one. Obviously this made it really sluggish to drive but it didn't fix the issue - although it did change it slightly. Whereas the mapped ECU required a full lift off from the throttle to recover power the standard ECU would boost fine then cut, then boost fine again then cut with the foot held firmly to the floor.

The only thing that gave me slight hope was cleaning the crank sensor. Last time I found a little bit of swarf on the end and cleaning that made it rev up perfectly for about a mile - then it started to play up again.

I'm properly at a loss now. Next step is to change the dual mass flywheel (clutch needs done anyway) so I'm hoping to find something in there.

Any ideas?