XJ DPF regeneration.
Discussion
The regen sequence depends entirely upon your driving cycle. If you have changed from, lets say, motorway driving to dense traffic, there will be a change in the cycle interval.
The prime trigger being the differential pressure between the DPF inlet and outlet.
Take it for a flat out blind! Not on a public road of course.
The prime trigger being the differential pressure between the DPF inlet and outlet.
Take it for a flat out blind! Not on a public road of course.
Mr Jenks said:
How do you know that is in a regen phase ? Does a warning light or something come up, do you notice a change in performance ?
You will notice a lot of smoke coming from the exhaust. It has only happened 3 times in the last 3/4 months, but I never noticed it before and we have the car two and a half years. It seems to have happened when I changed fuel stations, but the car is no longer on the motorway everyday and is doing much shorter journeys.Thankfully I had a Touareg which used to regenerate regularly, so I knew what it was and didnt panic, but other motorists think the car is on fire.
Firstly you must understand that any diesel will run on virtually any type of oil, parafin,central heating oil etc etc.We have had 2 S types in the shop where, following regen. Both cars has `took off` without use of the acel pedal and would not stop. Aided by the crap in the intercooler ( One had so much oil/ carbon/diesel ( around a litre)that it obviously had run on its` own crap. No loss of engine oil,no problems with the turbo either. Infact when I checked the engine oil it was way above the max, which is not good for the system at all. I have heard of a forced regen at the dealer using IDS, where one vehicle was left, redlining, with no stopping it, until it had burned all the contaminamtes in the intercooler.We feel that removal and cleaning of the intercooler would be preventative maintainence, especially with those of you who only cover low mileages. Both my problem cars were 06 with under 30k miles.I don`t think these are isolated incidents either , as my colleague( another independant) in the midlands has one in at present with the same symptoms.
The factory feel this issue and is well covered in the handbook. Trouble is these cars are very poor at maintaining chug chug up the shops and back, where the DPF quickly becomes full very quickly and the correct procedure is not followed. The vehicle I have in at present I am investigating further and I will report when I have time. The other car blew the engine after a high speed run, where again it `took off` with no stopping it, again the customer had noticed the oil level rising within the motor. It was covered by the extended warranty,but we had noticed the simular symptoms with a oily/carbon/ film around the back of the bellhousing. The DPF is linked to the cam covers/ back of the head via two pipes I believe, above the DPF, so possiblby the ingress into the motor is via these pipes, if the DPF is that full.
The factory feel this issue and is well covered in the handbook. Trouble is these cars are very poor at maintaining chug chug up the shops and back, where the DPF quickly becomes full very quickly and the correct procedure is not followed. The vehicle I have in at present I am investigating further and I will report when I have time. The other car blew the engine after a high speed run, where again it `took off` with no stopping it, again the customer had noticed the oil level rising within the motor. It was covered by the extended warranty,but we had noticed the simular symptoms with a oily/carbon/ film around the back of the bellhousing. The DPF is linked to the cam covers/ back of the head via two pipes I believe, above the DPF, so possiblby the ingress into the motor is via these pipes, if the DPF is that full.
RW774 said:
Both cars has `took off` without use of the acel pedal and would not stop. colleague( another independant) in the midlands has one in at present with the same symptoms.
again the customer had noticed the oil level rising within the motor.
The cause of the rising oil level is due to diesel getting into the sump because of incomplete regens which in turn can cause the engine to run uncontrolably on its contents.again the customer had noticed the oil level rising within the motor.
Owners are advised to keep a watchful eye(and nose)on their dipsticks for rising levels, the smell of diesel and then change the oil when noticed.
Agreed Diesel Piston, no fault found on Autologic with the motor or injection system, but logged were 22 failed DPF regeneration issues. Basically the 2.7 overfuels prior to regen cycle, to allow the exhaust to build up temperature and assist burn off the excess fuel stored in the DPF.Excess bore wash causes sump oil to fill with a % of the diesel.A new regen cycle just keeps adding extra fuel and the sump starts filling.
The DPF software monitors the owners driving style and when certain conitions are acheieved the cycle starts. Interupting the regen can be caused by braking, changing speed limits etc. It has to be consistant to acheve completion as the handbook states .When the cycle is broken,a failed regen logged and another will start when the conditions are correct .When a predetemined oil dilution is logged , by calculus a service message should be displayed on the dash.
Both my customers were alerted by the `DPF full` message. However, in my opinion both cars had much more diesel dilation than the 7% listed by the factory. Nearly a litre out of the intercooler!!
So Its` back to the good old check the oil weekly.That now explains why the other car blew the engine, due to the oil dilation being excessive, enough for it to leak out of every internal orifice and fill the intercooler, start dieseling to the point where it scoffed its own oil and seized.
Hope this helps, check your oil
The factory state some vehicles may require extra servicing outside of the standard schedule as a result of dilation.
The DPF software monitors the owners driving style and when certain conitions are acheieved the cycle starts. Interupting the regen can be caused by braking, changing speed limits etc. It has to be consistant to acheve completion as the handbook states .When the cycle is broken,a failed regen logged and another will start when the conditions are correct .When a predetemined oil dilution is logged , by calculus a service message should be displayed on the dash.
Both my customers were alerted by the `DPF full` message. However, in my opinion both cars had much more diesel dilation than the 7% listed by the factory. Nearly a litre out of the intercooler!!
So Its` back to the good old check the oil weekly.That now explains why the other car blew the engine, due to the oil dilation being excessive, enough for it to leak out of every internal orifice and fill the intercooler, start dieseling to the point where it scoffed its own oil and seized.
Hope this helps, check your oil
The factory state some vehicles may require extra servicing outside of the standard schedule as a result of dilation.
diesel piston said:
RW774 said:
God help those who live in the countryside where there is not enough road to carry out the regeneration
With respect regeneration can take only 20min@40mph once up to normal running temperature.Another safe bet is to ask the dealer/ independant to take off the hoses to/ from the intercooler during routine servicing.Any oil found , then I suggest the intercooler is remooved and cleaned with brake cleaner to despense with the oil residue altogether. Check to see how many failed regens are logged via your servicing independant. Easy to do with autologic or IDS.Too many Failed regens will mean interim oil changes. No bad thing.This is Preventative maintenance, preventing potential vehicle runaway and maintaining engine life. Also check your oil regularly, weekly is a must.
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