White smoke

smitty

Lieutenant
Joined
Oct 28, 2011
Posts
36
Likes
11
Location
Long Island N.Y.
Boat Make
Mannino
Installed new injectors in a cummins 6b 5.9 . Went from 9mm to 7mm injectors
and more white then before? the injection pump is in alinement . the washer where installed with new injectors. ??
 

Toolate

Admiral
Joined
Aug 6, 2013
Posts
6,479
Likes
2,402
Location
Southwestern CT
First Name
Ben
Boat Make
1998 36' Sabre Express CAT 3116TA's, 2015 ROS Scotia 16 Etec 50
Its not antifreeze burning from a head gasket? Does it smell like coolant?
 

Beamie

Commander
Joined
Jun 3, 2012
Posts
276
Likes
95
Need more info.......

Is this under load or sitting at idle? Wet exhaust or dry? What was the weather that day? cool, humid?

What do you mean 9mm to 7mm? Did you change to size and style of fuel nozzle?

White smoke usually indicates light load, too much air. Not sure where you guys are getting unburnt fuel in your head from. Usually unburnt fuel, poor combustion from say poor compression is indicated by blacksmoke. Too much fuel, not enough air..black smoke.
 

smitty

Lieutenant
Joined
Oct 28, 2011
Posts
36
Likes
11
Location
Long Island N.Y.
Boat Make
Mannino
7 mil meter nozzle injectore size . wet exhaust at idle, cool and dry days. nozzle was change 9 mm no longer made.
 
Last edited:

captjohn

Captain
Joined
Apr 12, 2013
Posts
840
Likes
405
Age
63
Location
Delray Beach, FL
Boat Make
Henriques
Unburned diesel fuel will result in white smoke. The cause is typically low compression, (rings, valves, or cold operation) Diesel pistons are not perfectly round, when cold they are smaller across the piston pins, when the piston warms up it expands more in the pin area because there is more metal there, at that point they are round and should get full compression. Get the engine up to temperature, under a load, at that point you should not have white smoke. You can get "steam" when warm, but that's a riser problem. Your never going to get black smoke from a low compression condition. Black smoke is due to rich condition too much fuel, not enough air. Bad injector, or pump, dad pump timing, clogged intercooler.
 

MDI45

Vice Admiral
Joined
Sep 1, 2011
Posts
3,648
Likes
1,098
Location
Freeport , new york
Boat Make
45MDI /28WB
I new of a guy with the same motor ..that had a fuel cooler.....cooler let go and the fuel tank loaded with water........white smoke at idle
 

Beamie

Commander
Joined
Jun 3, 2012
Posts
276
Likes
95
Your never going to get black smoke from a low compression condition. Black smoke is due to rich condition too much fuel, not enough air. Bad injector, or pump, dad pump timing, clogged intercooler.

Never, Really??? Listen, not wanting to start a tit for tat but these 2 sentences contradict one another. I have pulled my share of pistons and liners because of black smoke conditions due to low compression. Low compression is one reason for not enough air....causing a rich fuel condition causing black smoke. Low compression from scorn liners will also cause burning of sump oil......causing....you guest it....more black smoke.
 

Duke

Commander
Lite User
Joined
Dec 9, 2011
Posts
487
Likes
338
Location
Rye, NH
Boat Make
Dyer 29

codfather

Lieutenant
Joined
Mar 9, 2013
Posts
40
Likes
11
Basic Diesel engine theory states: black smoke = too much fuel and white smoke= too much air . Seeing that you downsized the injector I would check to see that it still dumps the same fuel quantity u may have to make an intake valve lash adjustment to get the right mixture
 

FPTMarineDiesel

Captain
Joined
Jan 21, 2013
Posts
770
Likes
268
Location
Waldoboro Maine
Installed new injectors in a cummins 6b 5.9 . Went from 9mm to 7mm injectors
and more white then before? the injection pump is in alinement . the washer where installed with new injectors. ??
How does the engine start? Does it fire right off when cranking with a very minimal delay, lets say within 5 seconds? If so, then it is not a compression issue.

Does it take more than 5 seconds to start and does it stumble or misfire at first and then start to become stable all the while it is smoking white with raw fuel odor? If so, then you may have an issue with compression or injector washer and or injector tip protrusion issues? What was the symptoms before replacing the injectors? Why were you replacing injectors, was it for this same reason? Does this B-Series Cummins have a VE Bosch Distribtor pump or a Bosch PLN P- Pump? Was the pump off for some reason and reinstalled by a dealer?

Sealing washer thickness changes where the spray of the nozzle is introduced into the bowl of the piston. If the wrong washer is introduced you can change the point at where the fuel is dispersed and can be putting fuel onto areas of the cylinder where it doesn't belong, this will give a white smoke unburned fuel odor, especially when at idle no load. Did this all come about only after changing injectors?

Diesel engines are already abundently rich with air when turbo charged, this is one reason why they are high in NO and NO2 emissions. Too much air doesn't give you white smoke and an unburned fuel smell. Timing, injector position (spray angle deflection and point of entry into the piston crown combustion chamber), valve wear, compression, water ingress (steam in cylinder), these types of issues will bring on white smoke.

If it were antifreeze, it would present itself as grey smoke and would smell sweet out the stern exhaust outlet, it would not burn your eyes and be strong in odor like fuel will. If it were a head gasket, you would push antifreeze out the overflow or around the cap when under a load, you would likely see higher than normal coolant temperatures and usually in an overflow tank there is some black soot residue showing like a skim coat at the top of the system.

Just some things to think about and put answers to in order to give the right direction.
 

FPTMarineDiesel

Captain
Joined
Jan 21, 2013
Posts
770
Likes
268
Location
Waldoboro Maine
How does the engine start? Does it fire right off when cranking with a very minimal delay, lets say within 5 seconds? If so, then it is not a compression issue.

Does it take more than 5 seconds to start and does it stumble or misfire at first and then start to become stable all the while it is smoking white with raw fuel odor? If so, then you may have an issue with compression or injector washer and or injector tip protrusion issues? What was the symptoms before replacing the injectors? Why were you replacing injectors, was it for this same reason? Does this B-Series Cummins have a VE Bosch Distribtor pump or a Bosch PLN P- Pump? Was the pump off for some reason and reinstalled by a dealer?

Sealing washer thickness changes where the spray of the nozzle is introduced into the bowl of the piston. If the wrong washer is introduced you can change the point at where the fuel is dispersed and can be putting fuel onto areas of the cylinder where it doesn't belong, this will give a white smoke unburned fuel odor, especially when at idle no load. Did this all come about only after changing injectors?

Diesel engines are already abundently rich with air when turbo charged, this is one reason why they are high in NO and NO2 emissions. Too much air doesn't give you white smoke and an unburned fuel smell. Timing, injector position (spray angle deflection and point of entry into the piston crown combustion chamber), valve wear, compression, water ingress (steam in cylinder), these types of issues will bring on white smoke.

If it were antifreeze, it would present itself as grey smoke and would smell sweet out the stern exhaust outlet, it would not burn your eyes and be strong in odor like fuel will. If it were a head gasket, you would push antifreeze out the overflow or around the cap when under a load, you would likely see higher than normal coolant temperatures and usually in an overflow tank there is some black soot residue showing like a skim coat at the top of the system.

Just some things to think about and put answers to in order to give the right direction.
Another thing to add to this:

If you replaced the injectors on the premise that the white smoke was due to the injectors, it may have been the wrong approach. If you have higher hours on the engine, a VE Bosch rotary distributor pump with KSB or KKSB injection advance, then you may have made matters worse by changing the nozzles. The reason is that the nozzle lower pintle valve control spring is now new and the opening pressure is nominal or slightly higher. If the pump cam is worn or the rollers and delivery valve then the pump may need to work harder to open the nozzle pintle valve. If this is the case then timing will be delayed and atomization will suffer and therefore combustion will be affected and compromised. Add normal wear and tear of the engine combustion chamber and you are amplifying an issue more with the injection pump possibly than with the injectors or cylinders. Just some additional things to think about dependent upon why you did the work in the first place and what the life on the engine is?

I am only jumping in because this can be resolved and diagnosed here as well as on Boat Diesel I am sure.
 

smitty

Lieutenant
Joined
Oct 28, 2011
Posts
36
Likes
11
Location
Long Island N.Y.
Boat Make
Mannino
No smoke! well very little. Did adjustment on valves and fuel pump timing.
Thanks everyone for in put.
 

BillD

Admiral
Joined
Sep 1, 2011
Posts
7,477
Likes
3,107
Location
Portsmouth NH, boating out of the mighty Merrimack
Boat Make
25 Terry Jason with Cummins 370 power
Installed new injectors in a cummins 6b 5.9 . Went from 9mm to 7mm injectors
and more white then before? the injection pump is in alinement . the washer where installed with new injectors. ??

If you do not find your answer here,
spend $25/yr and post the question over on boatdiesel forum.
You'll get an answer to your question.
 
Top Bottom