Euro4 DPF & Oil Consumption, *UPDATE*

[Nickthecook]

Sorry for new thread, but I needed this to be seen. So it looks like we're just about there at last. Tomorrow I will know for certain.

1) if you have a genuinely restricted DPF, the HPL EGR will only serve to make it worse it the majority of cases. I cannot stress how important it is to maintain that 2,00rpm - 2,200rpm when attempting to clear it. Every press of the gas pedal when you have a high exhaust pressure, will result in the throttle closing to achieve the desired differential pressure.

2) This is to all the others who are stuck in a cycle of 'Soot Filter Full' and horrendous oil consumption, look at changing your alternator. It would appear a faulty current can spike your sensor readings, but more importantly the freewheel diodes appear to switch the power supply from 12v to 12v ACC during charging (lift off mostly) if the freewheel pulley is buggered, the throttle doesn't appear to get any power and therefore closes. In a high mileage car, exoect lots of oil to be sucked from the sump due to the vacuum created by the throttle. The Throttle doesn't always open again ( on and off the gas pedal a few times can get it moving again) and therefore high boost can build up on the intercooler side. Change gear, the throttle opens and allows all the boost into the cylinders. Unlike petrol, diesel cars a fuel driven, therefore the increase in air makes no difference to the revs, but it does spike the exhaust pressure on it way out, triggering a soot filter full warning.

It also appear a a faulty alternator can prevent the ECM from picking up certain faults. When I changed the Alternator to ECM signal wire at the weekend, it straight away revealed an A/C fault which now has the fan running flat out. Anyone sceptical of the link between he two, check the ECM signal specifications in VIDA and you will find one for 'Alternator Freewheel Diodes and Throttle.'

I'll update tomorrow.

[osullivant]

Originally Posted by Nickthecook

Sorry for new thread, but I needed this to be seen. So it looks like we're just about there at last. Tomorrow I will know for certain.

1) if you have a genuinely restricted DPF, the HPL EGR will only serve to make it worse it the majority of cases. I cannot stress how important it is to maintain that 2,00rpm - 2,200rpm when attempting to clear it. Every press of the gas pedal when you have a high exhaust pressure, will result in the throttle closing to achieve the desired differential pressure.

2) This is to all the others who are stuck in a cycle of 'Soot Filter Full' and horrendous oil consumption, look at changing your alternator. It would appear a faulty current can spike your sensor readings, but more importantly the freewheel diodes appear to switch the power supply from 12v to 12v ACC during charging (lift off mostly) if the freewheel pulley is buggered, the throttle doesn't appear to get any power and therefore closes. In a high mileage car, exoect lots of oil to be sucked from the sump due to the vacuum created by the throttle. The Throttle doesn't always open again ( on and off the gas pedal a few times can get it moving again) and therefore high boost can build up on the intercooler side. Change gear, the throttle opens and allows all the boost into the cylinders. Unlike petrol, diesel cars a fuel driven, therefore the increase in air makes no difference to the revs, but it does spike the exhaust pressure on it way out, triggering a soot filter full warning.

It also appear a a faulty alternator can prevent the ECM from picking up certain faults. When I changed the Alternator to ECM signal wire at the weekend, it straight away revealed an A/C fault which now has the fan running flat out. Anyone sceptical of the link between he two, check the ECM signal specifications in VIDA and you will find one for 'Alternator Freewheel Diodes and Throttle.'

I'll update tomorrow.

Sorry but I am one of the sceptics. I have cured the high oil use and the blocked dpf issue in a 300kms 2006 185 xc90

Without changing my alternator or detecting any blown sensors. Other than those I damaged doing my amateur mechanics...

I still have not checked my timing which will be done tomorrow as my only remaining issue is lowish mpg.... at that stage I'll have a look at vida.. and check what you highlight above...

however I think these engines are complex but their principles of operation are not too complicated and as the problems are mileage related I think they must be related to worn or deteriorated mechanical parts... tappets and lifters, rings, turbo, pcv. and a cleaned out DPF...

[osullivant]

Checked timing today and it looked pretty good using my old marks... but when the locking tools and the mark on the crank shaft are used it was a half tooth out...

runs much smoother and accelerates much quicker... although the instanteous consumption is really frightening but the average, even in a few short runs is improving...

The insides of the piping to the intake manifold, when I bought this car first was almost blocked... after about 20k mls since it was last cleaned, there was only a small amount of gunge and this may well have been there since the few ks miles I drove with the old PCV..

It will be a few days before I get a chance to test things properly but the MPG issue may well be sorted..

Just need to sort the occasionally heavy steering now....

[jamie1131]

Originally Posted by Nickthecook

Sorry for new thread, but I needed this to be seen. So it looks like we're just about there at last. Tomorrow I will know for certain.

1) if you have a genuinely restricted DPF, the HPL EGR will only serve to make it worse it the majority of cases. I cannot stress how important it is to maintain that 2,00rpm - 2,200rpm when attempting to clear it. Every press of the gas pedal when you have a high exhaust pressure, will result in the throttle closing to achieve the desired differential pressure.

2) This is to all the others who are stuck in a cycle of 'Soot Filter Full' and horrendous oil consumption, look at changing your alternator. It would appear a faulty current can spike your sensor readings, but more importantly the freewheel diodes appear to switch the power supply from 12v to 12v ACC during charging (lift off mostly) if the freewheel pulley is buggered, the throttle doesn't appear to get any power and therefore closes. In a high mileage car, exoect lots of oil to be sucked from the sump due to the vacuum created by the throttle. The Throttle doesn't always open again ( on and off the gas pedal a few times can get it moving again) and therefore high boost can build up on the intercooler side. Change gear, the throttle opens and allows all the boost into the cylinders. Unlike petrol, diesel cars a fuel driven, therefore the increase in air makes no difference to the revs, but it does spike the exhaust pressure on it way out, triggering a soot filter full warning.

It also appear a a faulty alternator can prevent the ECM from picking up certain faults. When I changed the Alternator to ECM signal wire at the weekend, it straight away revealed an A/C fault which now has the fan running flat out. Anyone sceptical of the link between he two, check the ECM signal specifications in VIDA and you will find one for 'Alternator Freewheel Diodes and Throttle.'

I'll update tomorrow.

I think this is wishful thinking. Yep, a vacuum may be causing oil to be sucked into the engine but via what route? If everything is working as it should the combustion chamber should be sealed from the oil in the crankcase. I suspect you will be chasing this down until you change the piston rings.

[osullivant]

Have you tried a compression test...