XSeries-forum

Morning all. Did an oil change on the 4.0d x5 yesterday and while I was doing that I put the diagnostics on to give it a check. It came back with glow plug cylinder 4 faulty. Can this stop the dpf from doing a regen.

Yes, a single faulty glow plug can absolutely stop Diesel Particulate Filter (DPF) regeneration because the Engine Control Unit (ECU) requires all plugs to function to initiate the process, using them to generate intense heat (over 1000°C) to burn off soot, and if even one fails, the DPF system can be inhibited, leading to clogging and expensive replacements. (taken from Internet)

If your tailpipes are clean it isn't stopping a regen and may be faulty some time , thats how I see it , they do become incteasingly important on newer models though it seems , the e70 didn"t seem to care certainly the m57 ones ,the n57 possibly needs them but the tailpipe test is the key

If you change the plug (or plugs) change the controller at the same time. A faulty plug frequently causes the controller module to fail shortly after.

Also lubricate the plugs for a few days before you change them. The N57 (it’s a 3.0L not 4.0L) has a habit of snapping plugs due to them being fitted without lubricant at build. Always use ceramic lube when refitting. Snapped plugs can be a mare to remove and gets expensive. The B57 engine may be more friendly.

When buying plugs/controllers, do not mix brands. BMW specifically advise caution with Bosch plugs and any other brand of controller. Many of us have used BERU for both.

Not stopped mine doing a regen.
As long as the engine gets up to temp mine are ok and have been fore some time now.

For the F15 the manual says…..

The following conditions must be fulfilled for a regeneration:

The coolant temperature must be in excess of 75 °C
the exhaust-gas temperature before the diesel particle filter must be greater than 240 °C
there must be enough fuel (fuel reserve indicator light is not lit up). Whenever the reserve lamp lights up, the regeneration process is suspended.
no fault codes from the air mass system, exhaust emission system and sensors must be saved in the DDE
The fault codes 480A / 245700 (from F01) and 481A / 245800 (from F01) must display the status "currently not present"
Constant driving speed above about 60 km/h (approx. 38 mph). The optimum speed is about 100 km/h (approx. 60 mph).

No mention of glowplugs. There certainly was a time period when a single plug lost would stop automatic regen, so maybe BMW have changed things on later models so it’s not so critical any more - or it may have depended upon engine/year/model?. If you have a code reader that can check the soot/ash load, or when the last regenerate took place (should be every 500-800km) that will tell you if you have an issue.

Annoyingly I have exhaust gas back pressure too hgh today on my e70 x5 It was 55 mbar ( not certain of units) i think so cleared codes and went out for 40 miles at a high rpm approx 2.5 to 3k holding gears to keep rpm high and came back expecting the back pressure to be much lower and it was 75 now I did do a lot of idling and 3 days of short runs to work , clearing snow in the days before this etc . I think it night abort the regen if the back pressure is too high so high rpm isn't ideal but you would think if it gets hot enough it will clear itself out sooner or later .

I have noticed though once the dpf warming comes on it them comes on every run after about it seems 7 miles or so is maybe a time based thing , I also asked my scan tool do do a forced regen but it doesn't appear to have worked so will need to check coolant temp after a run , I have changed stats before on this car but it was a long time ago.
Currently on 177k , x6 has been brilliant in the snow but being a a pain now

I cannot find ash/ soot content in any menu on the scan tool (Foxwell NT 530 ) which is also annoying Not had any dpf bother till the injections threw the towel in last summer .

I have always said the glow-plug thing was a myth but maybe not with some cars.
All i know for fact is my 2 and 3ltr diesels both have one or more failed plugs.
Also my c250 merc has one failed but still does a regen.
VW now they might not regen with a plug failed but not sure on that.