Just driving home and my truck started to regen about 5 miles from my house. The usual routine for my truck is that when its doing a regen, its a little sluggish and unresponsive to the throttle, but its done that since new so nothing strange there.. What was strange was that when I parked in my driveway the rpms were jumping from 500-750 with my foot on the brake. It felt like it was going to stall out every time it dropped to 500 rpm, then it would surge up to 750, and so on. When I let go of the brake, the rpm's would climb to around 1200, but not smoothly. It would surge around 500 rpms at a time. Anybody experience anything like this? Ive got 4000 miles on her now and since new, it likes to do a regen with every tank of fuel, usually when the distance to empty is around 90 miles or so, like clockwork.

 

I've never seen my rpm drop below 750. It should stay around there with your foot on the brake because with the break depressed there should not be any automatic throttle control related to a regen. Might want to get that check out at the dealer.

 

thats what i'm thinking too...i wonder if it has anything to do with the fact that i'm blowing a cloud of black smoke when i press the throttle? I took it the dealer for that and they said they couldn't find anything wrong with it. I see quite a few 6.4's around now and they all have nice clean exhaust pipes, where as mine are sooo black.

 

sorry to jump in and ask a question but i will be picking up my '08 F350 next week. what is a regen?
Thanks!

 

a regen is when the diesel particulate filter(dpf) has collected enough soot to call for it to be burned off. There are sensors that check backpressure among other things, and when the filter needs to be cleaned, the truck will go into a high idle, around 1200 rpm's, and burn off the soot by injecting fuel into the filter and burning it off. The exhaust temps are very high while this is happening, and it usually lasts around ten minutes or so? If you do a search on dpf or regeneration, you will find plenty of reading material. Good luck with the new truck! You're gonna love it

 

That does seem like a strange thing for the truck to be doing. Might want to get it checked out if it keeps up.


On a un-related note. This is just a thought but maybe we should get one of the mods to place a "read first" thread at the top of the forum with information about the re-gen cycle?

 

Ok might be an obvious question are you running ULS fuel? Also what kind of driving are you doing? All highway or all city stop and go?

 

Sounds like your DPF is cracked or damaged. I would take it back again and have them look over the DPF very carefuly.

 

Agreed, sounds like a damaged particulate filter, is the DPF still on the truck? I have to ask because there has been some successful removal of the DPF with slight retuning.

 

Mine did a regen on my way home last nite it started with a stutter they fuel dropped down to 7-10 mpg for about 15 min. Is this the norn.

 

Depends on what your truck is, but yes that could be normal.

 

I like my warranty so I havn't taken off the dpf. As far as fuel goes, always ulsd and also cetane booster. I was using Ford additive, but I just put in the diesel kleen gray bottle to see how that works out. I didn't notice any real difference with the Ford stuff. Most of my driving is done on the highway, avg speed of 70 mph or so, and still getting roughly 14 mpg hand calculated, so i'm not complaining about that at all. Guess its time to visit the dealer again and hopefully they will know a little more about this engine and emissions setup than they did last time. Its so frustrating when I read about TSB's and other peoples experiences and relay the info to them, they just look at me like I dont know anything.

 

I'm glad to see y'all are paying attention to what I write.

If there is black smoke from the tailpipe, the filter is cracked. The root cause of what cracked it needs to be discovered and repaired. A filter will crack from soot overload due to a "dirty" running engine, OR the fuel being injected during regen isn't enough to cause the DOC to come to the proper temp. Also, the filter could have been overheated at one point causing it crack. There are many possibilities, but the unfortunate thing is, most dealers won't have the experience necessary to discover the problem.

 

I was transfered down to Richardson TX Monday (3/3/08) and coming down 40 between Memphis and Little Rock my '08 PSD went berzerk for about 15 sec. I thought an injector harness on one bank had come loose or disconnected, but it cleared as quick as it happened. I continued the trip arriving here in Plano Tuesday. This morning when I got to work, I noticed the high idle deal, around 1100 rpm and the exhaust was hotter than 3 barrels of Hell. I figured it was a "burn" so I let it go. I waited 10-15 minutes, and it still didn't idle down, so I shut it down and went to work. It did the same thing on the way back to motel this evening and still is high idling. Not with foot on brake or sitting at a light, but I would think it has had enough time to clear the DPF. My exhaust pipe ends have always been very clean and I don't know or remember this happening prior to the other day. By the way, on the trip down here I averaged a little over 16.5 (hand calc.) I thought that was OK for just 4000 total miles on it.

Any suggestions appreciated.

Bill in KY

 

Soot in the tailpipe IS a defective DPF...Period....And it may not throw a code..mine did not..If the dealer and the diesel folks know anything about the DPF function the black and sooty tailpipe is enough to determine a bad DPF.The defective DPF affected the all over performance of my truck. By the way..keep a eye on your fuel level with low fuel these things blow white smoke and will run rough..That is the trucks way of telling you that you need fuel (air in the lines) It is in the manual..