diesel white smoke (again, sorry!)

Billjratt

Billjratt

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I make clouds of white smoke on startup, until the throttle is given full burst for a second or two.
Then the exhaust returns to it's normal self (just another smelly 30yr old engine).
I suspect a sticky injector and will have a go at cracking the HP unions to discover which, when the weather gets a bit better.
My question is though, why doesn't it sound like there are only 3 cyls firing? (it's a perkins 4108) it sounds perfectly normal under error conditions.
Could the unburnt fuel be added during the exhaust stroke due to an injector failing to shut? If so, I'm going to have difficulty identifying which cyl is the culprit as I'm used to working by ear.
I did have a dirty filter incident during the Summer, but must have motored for >100hrs since then, surely that should have cleared any debris?
Is it recognised practice to pull the injectors and compare colours as I used to do with sparkplugs?
Finally, what's your favourite "miracle fuel additive", and is it worthwhile re-routing the spillback pipe to prolong running on pure additive, having filled the filter with it. I used to have to do this to get my car through the emissions test at MOT time, but never bothered up to now with the boat.
Your experience-related replies eagerly anticipated...
Thanks.
 
White smoke

White smoke is usually water vapour, black smoke is excess diesel, blue smoke is burning oil.
Don't worry, there is nothing wrong with white smoke, it usually only last for a few minutes until the engine has warmed up, and does no harm. George.
 
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Rule 1: if it starts without drama, pulls away, delivers thrust, makes a regular sound, start up exhaust dissipates when warm...well, hey you've got a fully functioning engine!

Rule 2: stick with Rule 1 at all times.

So, no need for any intervention, including additives to the fuel - unless you know you've got a fuel problemo - ie sluge in the filters and/or water in the filter bowl.

Injectors can perform over many hundreds of hours without the need to pull and recalibrate.

Sounds like you've no need to join the "worried well" as far as your engine is concenrned!

PWG
 
GeorgeLlewellin said:
White smoke is usually water vapour, black smoke is excess diesel, blue smoke is burning oil.
Don't worry, there is nothing wrong with white smoke, it usually only last for a few minutes until the engine has warmed up, and does no harm. George.
Click to expand...

That's only half right. You can in fact get dirty white smoke, but this could easily be steam as you suggest. It's easy to check though as steam soon condenses into water droplets and dissipates. It also does not smell! If it leaves an oily residue and hangs about as a smelly cloud worry. If is dissipates quickly after starting and does not smell any worse than when running normally it's just taking time to get water through. Check your coolant pump impellor.
 
for what it's worth I would agree with above.

momentary white smoke wouldn't keep me awake.

Would take 10mins to inspect for possible sources - i.e. milky coloured oil on dipstick?, any water in fuel line/water separator?, water back siphoning thru exhaust? (siphon break fitted?), condensation?

like yourself, I tend trust my ear - if engine sounds happy and gauges confirm this, then it more than likely is..

rgds
cimo
 
Cant really see how it can be steam from a cold engine and exhaust!

More likely incomplete combustion due to cold start preheat failure. Certainly unlikely to be any one injector, and pulling them they will all look the same anyway - they dont burn like sparkplugs! If you suspect them, the spray pattern has to be checked. Many diesel specialists will do this for free if you take the injectors in to them - it only takes a few minutes. It can be done on the engine but it is messy and dangerous. Dangerous because if you get sprayed the injector has sufficient force to inject you with raw diesel - usually giving you blood poisoning!

The 'dirty filter incident': did dirty diesel get past the filter into the injection system? If so, that could be the cause, and the pump and injectors may need checking - again a specialist job, but if the smoke problem identiably started then, then that could be it. It takes very little to cause problems, which is why diesel has to be so carefully filtered

On the other hand, a puff of white smoke on cold start is fairly common on older engines begininning to wear, and is nothing to worry about - just a bit antisocial in the marina! The likely cause then is valves not seating quite 100% or valve stem leaks, which reduce compression and combustion until the engine has started to warm up a bit.
 
Don't worry about it. If it dissipates it's steam and older engines are not alone in spewing out condensation products as steam the minute they start, have a look at many modern cars on a cold morning, some of them have exhausts that positively drip water as well as spew out steam. This usually goes as they warm up but of course there may still be steam on boats as water is injected into hot exhaust gases, it is logical that some gets turned to steam that may not condense before it is ejected from the hull outlet.
 
Disagree - my engine exhaust steams only when it is warmed up then it does it all the time. Its normal for that kind of engine. Petrol engine cars produce steam as they warm up - not at the moment of starting from cold, nor does it clear when 'given a burst of throttle' - that makes it worse until things have warmed up a bit more. Not at all what OP is reporting.

I wouldnt worry unduly about it myself either, and certainly didnt bother when my old Perkins engined diesel Montego used to do it! But OP is asking specific questions, wanting to take his engine to pieces, and seeking advice on how to set about seeing whether he can stop it happening. Specific questions - specific answers.
 
Old Harry, You get steam from a cold engine because the exhaust still comes out hot and instantly boils off any residual water in the exhaust system and water trap. If the intake is not blocked or restricted the water immediately injected into the exhaust will stop this but if the intake is partially blocked or the pump impellor is knackered it will steam off until the throttle is opened sufficiently to restore flow. Exactly as the original post described.
 
Thanks for response guys.
No, I don't have a steam engine - the exhaust configuration won't do that, and it is instantly "switched off" by blipping the throttle.
Additionally, ( I know I should have mentioned it), the white smoke lingers, and there is evidence of some oiliness on the surface of the water ( however the engine is old and this may be there anyway) I didn't get downwind to see if it smelt like a paraffin blowlamp that's gone out, but I suspect it will.
I didn't get any feel for what is your favourite additive/cleaner, and am Googling away as we speak. Anyone used BG 244 with success?
http://www.fueltechexperts.com/2008/08/20/we-try-bg44k-and-bg244/
I thought this made interesting reading, and will probably try it before applying spanners.
 
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Wont argue. Just never seen it happen in 25 years dealing with engines including managing a fleet. Maybe I got lucky!


And BillJ - I dont have favourite 'cleaner'. I never found one that made the slightest difference except to my wallet!
 
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Yup, it's not cheap stuff to buy, but I've gone ahead and ordered some.
The thing is, there could be any number of inherited problems in unit of this age, so it's difficult to get a decent reference point to start from without inspection/reconditioning - and that is always a jar of worms!
I will report results sometime next season, as it will take that long to burn the fuel.
Thanks again guys.
 
Billjratt said:
Thanks for response guys.
No, I don't have a steam engine - the exhaust configuration won't do that, and it is instantly "switched off" by blipping the throttle.
Additionally, ( I know I should have mentioned it), the white smoke lingers, and there is evidence of some oiliness on the surface of the water ( however the engine is old and this may be there anyway) I didn't get downwind to see if it smelt like a paraffin blowlamp that's gone out, but I suspect it will.
I didn't get any feel for what is your favourite additive/cleaner, and am Googling away as we speak. Anyone used BG 244 with success?
http://www.fueltechexperts.com/2008/08/20/we-try-bg44k-and-bg244/
I thought this made interesting reading, and will probably try it before applying spanners.
Click to expand...

This is what I know about white smoke - as opposed to steam - from diesel engines,

IF it is smoke then IT WILL be one or more of the following:

Engine/pump timing out
Fuel starvation to the pump causing the pumps timing not to operate correctly
Low engine compression
Water/petrol in the fuel

Steam is something very different from smoke and the causes are not related to list above in any way, in a marine engine I would be looking at the cooling and exhaust systems not the engine as such. Insufficent flow of raw water is the most probable cause of steam, perhaps reving the engine after startup gets the raw water pump operating.
 
Billjratt said:
Thanks for response guys.
No, I don't have a steam engine - the exhaust configuration won't do that, and it is instantly "switched off" by blipping the throttle.
Additionally, ( I know I should have mentioned it), the white smoke lingers, and there is evidence of some oiliness on the surface of the water ( however the engine is old and this may be there anyway) I didn't get downwind to see if it smelt like a paraffin blowlamp that's gone out, but I suspect it will.
I didn't get any feel for what is your favourite additive/cleaner, and am Googling away as we speak. Anyone used BG 244 with success?
http://www.fueltechexperts.com/2008/08/20/we-try-bg44k-and-bg244/
I thought this made interesting reading, and will probably try it before applying spanners.
Click to expand...

Then you are probably right, it's smoke. The fact that it instantly dissapears with a throttle blip indicates that the engine condition is probably fine and the injectors are unlikely to be a problem. It could well be that the fuel pump is one of those with a starting valve that gives rich fuel when starting from cold. If so it will indeed need a throttle blip to reset it.
So I have a new question for you!
Does this only happen on initial start? In other words if you give it a blip on the throttle and then return to a tickover does it still smoke? If it doesn't no worries. If it does then it's more likely to be a fuel pump problem, possibly, dependant on the pump, a stuck or broken spring. Either way I doubt very much that fuel additives will help.
 
I have had this (white smoke - no Vatican in sight) before, on a volvo penta md11d, when the tip of one injector broke and some of it disappeared via the exhaust. However this undeniable injector problem was permanent.
My current problem is intermittant inasmuch as it just seems to need a good blasting to free-up and operate properly.
Forget the steam, it's a freshwater cooled system with a cooled manifold conected to about 2 metres of dry lagged iron pipe going to a cast water injection unit and then to a short rubber pipe. Nothing has time to get hot enough for steam, and there is plenty of peepower in the saltwater telltale. no water in the fuel filter bowl, and good flow, can't see a timing or high-pressure pump problem correcting its-self so predictably, no loss/blow-out of freshwater coolant.
If the elixir of life turns out to be snake oil, I'll have to go through the original plan of trying to identify the dirty/faulty injector (all professionally refurbished about 300 eng.hours ago)
Anyway, as I said, it'll be a while before I have anything to report, so back to hibernation....
CU next Spring!

EDIT - Boatmike, tx fr reply we were typing in stereo I think.
Yes, it is initial startup, but the cold start device was not employed, and cranking was not prolonged. I let the engine run in "smoke mode" just to see if it would clear naturally and it didn't, so I throttled it with immediate success, and clean at idle revs. I'll have to test with multiple starts to see if it's repeatable once it's 'awake'.
 
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I would bet its something to do with the 2 mtrs or so of lagged iron pipe. Dont forget the exhaust gas IS hot enough to produce steam and on a cold start I would imagine the inside of this pipe would be coated in condensation. Lots of revs boils all the water away hence no "smoke".
 
Steam

At the risk of being regarded as a nerdy scientist, the main product of ALL internal combustion engines is in fact steam (boiled water). You are converting all of that expensive fuel (hydrocarbons) to carbon dioxide (and enraging the tree huggers), and water. The only reason that you see it on a cold morning is because the steam is condensing faster in the cold air.
Dont know if it helps solve your problem, but at least you know that steam is not something to be ashamed of.
 
I see no steam - only water! ?

AllanJ said:
At the risk of being regarded as a nerdy scientist, the main product of ALL internal combustion engines is in fact steam (boiled water). You are converting all of that expensive fuel (hydrocarbons) to carbon dioxide (and enraging the tree huggers), and water. The only reason that you see it on a cold morning is because the steam is condensing faster in the cold air.
Dont know if it helps solve your problem, but at least you know that steam is not something to be ashamed of.
Click to expand...

Quite right, but in a marine engine the steam (superheated at is comes out of the cylinder) is usually condensed rapidly in the exhaust elbow and becomes part of the cooling water and is therefore seldom seen - strange things are a foot in this engine! PhD anyone?
 
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