PDA

View Full Version : Blue smoke on Cold Start



piersbc
12-21-2004, 10:35
I've been seeing more blue smoke on cold starts lately. After 5 seconds its all gone and the truck runs fine. I don't get any blue smoke on warm starts. I'm installing new JK quick heat glow plugs this week also. Just wondering if this blue smoke is something I should be checking in to.

More Power
12-21-2004, 10:57
Given the cooler temps, it sounds normal..

MP

piersbc
12-21-2004, 11:05
Where do you think the oil making the smoke is coming from? Just a colder engine with more tolerences? It's still 40 degrees here.

cruzer
12-21-2004, 11:36
piersbc, The smoke is should be diesel fuel. Next time have someone start it while your at the tail pipe.

piersbc
12-21-2004, 11:53
I thought blue smoke was oil....and white was unburned fuel....?

Hubert
12-21-2004, 13:58
Pretty normal. Mine (~109,000 miles)does it when its cold in the mid 30's F and gets worse in the 20's F a dark grey a little bluish when its cold the colder the bluer/darker. Its not really injecting enough diesel to be the heavy black smoke yet and the combustion is still relatively cold compared to operating temps and I think its a little condesation (white smoke) that lightens the color when the exhaust pipe is cold.
Add older injectors (not as a crisp effeceint spray "atomizing") coupled with a weak glow plug or 2 causing some cylinders to "crank up slower" its just things getting tired with age pretty normal.

Also another big big thing is starter cranking speed. Faster cranking speed means more heat for combustion. A good additive with cetane improver helps with much easier cranking too - especially in the cold.