Low power D40 after turbo failure.

[Ukracer]

Hi I am not sure what else to title my problem so here goes.

Having had my 07 D40 going into limp mode over a few years it was not a great issue as it was always fine when it was towing.

Step forward to a few weeks ago my son decided to identify the cause as we had fitted 2 new SCV's and a fuel pressure sensor.
Then it started cutting out when at traffic lights so using a guide of youtube (arrggg) he tried to force a regeneration as described on you tube.

This resulted in recovery by the RAC with a broken turbo and oil everywhere.

Moving on a couple of weeks a new turbo was fitted. This was after all the intercooler and associated piping was steam cleaned. Started up perfect but exhaust was obviously full.of oil despite being washed out. As large quantities of black smoke covered our estate (it was that bad.)
Anyway we decided to steam clean the DPF as the DPF light had by now come on.
That seemed to.be the secret BUT after driving about a quarter of a mile DPF light comes on again.

So along comes my sons mate. With his snapon from work. He managed to turn of the DPF light.
But a trip up the road brought on the DPF light in exactly the same place on the road. (Inc limp mode)

So a forced regeneration was started. Very smokey at first but around an hour later it was running very clean.


Yet another trip up the road and "Damn" DPF light back on. (Same place and inc limp mode)

The most confusing thing is it's not making the power it used to even before the DPF light comes on. It ticks over and runs good otherwise.

 

[Ukracer]

The snap on read the codes and turned the light off. It definately regenerated as there was lot of smoke and heat to start with.

Our problem is that since cleaning and refitting everything when you take the truck up the road the dpf light is off from the start, but the truck has no power. When the truck reaches a certain point (within feet) the dpf light comes on and there is even less power.

What we are trying to establish is whether the snapon was just turning off the light and not deleting the fault. Leading to the DPF fault coming back after the truck has travelled a certain distance or for a certain time.

I do have access to.nissan consult III so we will be trying that.

 

[Old.Tony]

I remember something about the DPF fault being a special kind of fault in the ECU - but also that those workshop tools, if they clear the light, also clear the code, so what you're seeing is something else. There are at least 3 possibilities:

Bad pressure sensor. This is a small black unit that lives up on the inside guard fairly close to the left hand bonnet hinge. It has two black rubber hoses that connect it to two metal pipes that lead up from the front and rear of the DPF. This pressure sensor monitors the pressure differential between front and rear of the DPF so it can determine if the DPF is blocking up and needs a regen.

Bad DPF sensors. These are sensors directly in the front and rear of the DPF. Something goes wrong with them (don't ask, I don't know) and the DPF light starts coming on, clouds of white stinky smoke etc. Limp mode can and will happen. The quickest solution to these going bad is to buy a replacement pair from auggie (contact details in first post of this thread). Note that the DPF will need to be "modified" to use these sensors (I am not supposed to tell you that this requires removal of the core material of the DPF).

Bad ground on DPF. The sensors obviously work electrically and if the ground circuit is compromised, the sensors may not provide the correct feedback to the ECU, which could make the ECU produce errors.