Car losing power after reaching around 3000rpms

Goudy

It's not only the DPF that causes problems with diesels.

Soot and engine oil (fed in from the crankcase breather) can clog up the EGR valve and cause it to stick open, the starves the engine of air, as it's being replaced by exhaust gases and you usually notice the exhaust produce thick clouds of black sooty smoke.

Again, soot/carbon can clog the wastegate of the turbo and create an overboost as it cannot regulate the spool by opening the gate at high load/speed. Inlet pressure sensors detect this and trip the car into a low rpm, limp mode.

With the problem being engine speed/load related, I would hazard it may be turbo or in fact a fuel pressure problem in the fuel rail/injectors/fuel filter.

A leak, blocked fuel filter or worn injectors will reduce the injection pumps ability to maintain rail pressure and when demand it high (3000rpm and above) it detects this so tends to restrict the power with a trip into restricted, limp mode.

The above faults tend to reset with the ignition, so turning the engine off and back on again will reboot the car, that is until it reaches the same point again and trips again.

The cheapest option would be to replace the fuel filter first, there's been a recent temp drop and I doubt they've starting winterizing diesel fuel yet, so it could be clogged a little and the cold fuel is a little slow to move through it causing it to starve a little at high load.

AdrianC

MrBrindle wrote: »

Haha, yeah I know. I've read of conflicting info online regarding the regen. Some people/articles mention a swift drive at 70mph does the trick, others say you need a good 30-45mins of solid 50mph+ driving. What is correct?

You need to get the exhaust PROPERLY hot.


Sitting at a bimbly cruise on a clear dual carriageway or motorway won't do that - the car's not working particularly hard, and there's a lot of airflow to cool the exhaust. You need to get some load on the car. Drive it hard.