We have a 2003, U320 with 103.00 mi. After driving 150+ miles, when we decelerate quickly a cloud of white smoke blows out the exhaust. Is anybody familiar with this situation? Any suggestions?
Bob, not familiar with your situation, but white smoke usually indicates either unburnt fuel or water in your system. Does it smoke under a load? It's possable you have the start of a fuel pump issue.
Bob,
Have you lost an abnormal amount of antifreeze from your overflow tank now that this smoking has started?
Have you gained oil level on your dipstick?
Pamela & Mike
Probably a lift pump issue or filter clog. Lift pump can deliver uneven pressure as can partially clogged filter. White smoke from head gasket is usually present at all times rather than decelerating. White smoke you have is usually excess fuel. How much smoke? How is it running? Check smoke when you start in the morning. Check coolant tank level. Need to find cause sooner than later. Might have someone follow you.
Filter is my number one suspect.
Pierce
Todays fuel is the worst.
Have you ever used (good) fuel injector cleaner?
Now may be a good time. (the stuff ain't cheap) = HOT SHOT SECRET
I doubt the pump is your issue.
White = Unburnt fuel entering the exhaust stream..
Blue = Lube oil
Black = excess burnt fuel
pc
You can tell if it's steam (antifreeze) or unburnt fuel. Try revving hot engine and see if it smokes. Carefully smell the exhaust. if it has a slightly sweet smell it's antifreeze. If its acrid and makes your eyes water it's fuel. Look for white deposits under the oil filler cap That's antifreeze in the oil.
Keith
Thank you all. The smoke goes away under load. Engine runs fine. Oil level steady. I'll keep a closer eye on the antifreeze. Today there was not any smoke. We did find a couple used fuel pumps in a compartment. How long are fuel pumps good for?
I'll inform the list of what we find out.
Bob,
With a clogged filter, it is not unusual for some of the contaminants to settle down to the bottom of the canister overnight allowing the engine to run normally for quite a few miles the next day, especially if flat terrain. If your engine loses power and you are looking at the possibility of being stuck somewhere, take the wooden part of a hammer and bang on the canisters for 30 seconds or so (with the engine stopped).
Pierce
I'm far from a diesel expert, but it sounds as if something in the fuel-control system is allowing too much fuel into the cylinders when decelerating. If you can find a really good diesel shop they might run some diagnostics.
We also have a 2003, older build number than you, and are still on our original fuel pump. Are there any records of when/why the PO had it replaced in your coach (especially if you think it's been more than once)?
When ever we saw white smoke on the fishing grounds the first suspect was a fuel injector and 9 times out of ten, that's what it was. Diesel fuel cools/lubricates the nozzle however the slightest amount of water may destroy the integrity of the orifice.
Our GMC with the Duramax was tough on injectors, had some replaced a couple times mad all replaced once. Symptom of the bad injectors was white smoke out of the exhaust at idle.
All injector replacement was at GMC expense.
Roland
We haven't seen any smoke since our last post. However, did notice that after servicing the engine that the oil was above the full line. Now it is in the middle of the safe area on the dip stick and has been holding steady there. Could too much crankcase oil have been the problem?
no.. pc