Am I correct in this....

[osullivant]

As I understand it the D5 185 has tremendous control over when and if a particular injector injects fuel into the cylinder and on some strokes, subject to the load on the engine, no fuel will be injected so that there will not be a detonation in that particular cylinder on that stroke.

If this is so, all that will go through that cylinder is Air; from the air-filter, some from the PCV and maybe some from the EGR.

I have just changed the piston rings, with decoked and skimmed head lapped valves stem oil seals etc, entire engine ductwork etc all drained of oil and refilled, dpf cleaned engine sounds much better, and definitly had more torque and was more economical until......

took on test drive initially very quiet and very economical, then faults.... then injectors loosened so less than ideal losing compression from at least 2, back to home, soot filter full....

trace other faults to bad connections and eliminate

tighten injectors force regen.... regen said to be successful.

10 minutes into test drive 2 soot filter full, etc. this test route is up and down some good hills.

on return investigate to find two injectors loose again and the interesting bit.... what is being fired out is dirty engine oil in a mist, the area around them was dripping in the stuff especially the underside of the stay bar

(I wrapped the unions in tissue so I know this is not fuel spraying)

My conclusion is that on the run down the hills the cylinders were not being fired so were basically just compressing unburnt intake air which was itself oil laden.

If i am correct this must be coming from the PCV ( I have a brand new original volvo turbo which has only done 600 miles)

My theory is that the oil is being vacuumed out of the oil separator due to a fault in the valve....

(when I previously fitted a catch can I got no oil in this pipe but of course this would have prevented a vacuum from developing....)

My plan is to change the top of this valve using part 8642424 and perhaps the innards from a donor s60 which never used oil..

Comments?

[Clan]

Originally Posted by osullivant

As I understand it the D5 185 has tremendous control over when and if a particular injector injects fuel into the cylinder and on some strokes, subject to the load on the engine, no fuel will be injected so that there will not be a detonation in that particular cylinder on that stroke.

If this is so, all that will go through that cylinder is Air; from the air-filter, some from the PCV and maybe some from the EGR.

I have just changed the piston rings, with decoked and skimmed head lapped valves stem oil seals etc, entire engine ductwork etc all drained of oil and refilled, dpf cleaned engine sounds much better, and definitly had more torque and was more economical until......

took on test drive initially very quiet and very economical, then faults.... then injectors loosened so less than ideal losing compression from at least 2, back to home, soot filter full....

trace other faults to bad connections and eliminate

tighten injectors force regen.... regen said to be successful.

10 minutes into test drive 2 soot filter full, etc. this test route is up and down some good hills.

on return investigate to find two injectors loose again and the interesting bit.... what is being fired out is dirty engine oil in a mist, the area around them was dripping in the stuff especially the underside of the stay bar

(I wrapped the unions in tissue so I know this is not fuel spraying)

My conclusion is that on the run down the hills the cylinders were not being fired so were basically just compressing unburnt intake air which was itself oil laden.

If i am correct this must be coming from the PCV ( I have a brand new original volvo turbo which has only done 600 miles)

My theory is that the oil is being vacuumed out of the oil separator due to a fault in the valve....

(when I previously fitted a catch can I got no oil in this pipe but of course this would have prevented a vacuum from developing....)

My plan is to change the top of this valve using part 8642424 and perhaps the innards from a donor s60 which never used oil..

Comments?

you must change the injector mounting spring clamps and copper washer each time you remove them , they loose tension every time you re use them .
I would fit a new breather box and make sure the drain hole into the cylinder block at the bottom is not blocked and go from there .

[dingov70]

Many modern diesels will cut fuel until such time as lowering revs require fuel to maintain engine speed . If you have injectors loose in head any fuel injected may not burn , be ejected up the sdies of the injector collecting any oily dirt in the process & giving you the oily deposits .

If your engine was drawing that amount of oil into the cylinders I would expect it to either smoke badly / run like rubbish / stink ,BUT I would be surprised if it did not begin to runaway ( uncontrolled engine acceleration ) as its simply see's the engine oil as fuel & burns it .

If you are getting DPF full messages & regens are not cleaing the soot , It may well be worthwhile to remove & pay for the DPF to be chemically cleaned .

For video of runaway diesels , simply view Youtube , the results will make your wallet panic

[osullivant]

Originally Posted by dingov70

Many modern diesels will cut fuel until such time as lowering revs require fuel to maintain engine speed . If you have injectors loose in head any fuel injected may not burn , be ejected up the sdies of the injector collecting any oily dirt in the process & giving you the oily deposits .

If your engine was drawing that amount of oil into the cylinders I would expect it to either smoke badly / run like rubbish / stink ,BUT I would be surprised if it did not begin to runaway ( uncontrolled engine acceleration ) as its simply see's the engine oil as fuel & burns it .

If you are getting DPF full messages & regens are not cleaing the soot , It may well be worthwhile to remove & pay for the DPF to be chemically cleaned .

For video of runaway diesels , simply view Youtube , the results will make your wallet panic

Thanks for that, I understand what runaway is, but it is not likely at this level, especially when the cylinder is loosing compression so little if any prospect of detonation.

I can change the top of the oilbox relatively easily, the valve in the top is my chief suspect at this stage so I will try that, I previously took off the oil box and cleaned it, the openings to the block were all clear with just a film oil that had the consistency of gloss paint covering the innards, I suspect this is just years of operating properly...

I would like to fathom out the operation of this oilbox top..., it seems to consist of a valve and diaphragm

Yes I should have replaced the retaining clips... especially as I have had these injectors in and out 5 times already, I fitted new copper seals....

I had the DPF off and cleaned in the past and it lasted a few hundred miles and it was that subsequent failure that led me to changing the turbo for a second time...

I am not removing the dpf again until I stop the cause of the failure...

[Rooster]

You have done a hell of a lot of work to engine

What was the original fault that made you do it all in the first place??

[osullivant]

Originally Posted by Rooster

You have done a hell of a lot of work to engine

What was the original fault that made you do it all in the first place??

first was noises in the head coupled with some oil use,(new rockers etc)

then ferocious oil use which according to this forum and other sites must have been from a leaking turbo. (new turbo core)

then really bad performance filled soot filter etc. Turbo and actuator re programmed...(waste of time and money)

then new(secondhand) actuator... then brand new out of the box new turbo.... then new tyres and 4 way alignment. then rings and now back to PVC which was one of my original thoughts...

in between, new maf, tmap, exhaust temp sensors, coolant, light bulbs, battery, tow bar bluetooth parrot.... and on and on...

blood sweat and tears and cash...

Today I ordered the 8642424 and injector clips and this is it.... unless the car is fabulous...I will sell it. I can get €2500 back from the government here if I scrap it or export it, so I will sell it to the UK complete with new turbo, and new Pirelli scorpions for a very good price or else break it here... any takers for a 2006 xc90 ocean race version with a chequered past....

it does seem that the beginning of the end was frequent oil changes which removed the gunk which was actually providing the compression around the pistons....

I guess I am a self delusional tenacious optimist ....