Originally Posted by Falmouthboy
OK - Daft question, but how is my DPF ever going to regenerate. I read everywhere that I need to go for a good 30 minute run at above 2500 RPM, however, to do this in a 330d Auto you need to be tanking it at 90 MPH. That can't be right - do I need to lock it in 4th and do a 30 min run? Not easy on Cornish roads!
If the regenerations are working correctly you won't need the high revs and or distance.
The autobox will be controlled by the ECU, just don't fight it and put it in a higher gear manually. I find it will want about 1,800rpm, during the first stages of a regeneration. Doesn't up change as normal, during a regen. But if you are cruising at around 60mph, it will drop into 6th during the regeneration.
I was discussing regenerations with one of BMW's technical managers, he said if you notice a regeneration "just give it its head". So if I'm driving locally and notice a regenertion start and get out on the open road, I'll let it cruise in 5th to assist an efficient regeneration. Mine usually are complete after about 8 miles, gearbox back to normal.
I think the real issue is, if there are problems with regenerations, then a harder drive over distance is required, to ensure the regeneration can be successful.