Thread: The curious white smoke scenario

IIRC, the TD5 doesn't inject any fuel in a overrun situation, so perhaps the engine is just turning, no fuel, cold, no glowplugs, and basically you are starting the engine cold for the first time on the hill?
Have you tried idling the car for 5 mins before you leave? or accellerating a little every min or so on the way down?

interesting scenario though!

Further thought:
Could water be condensing in the cylinders, then when you do finally accelerate, it needs to be evaporated?


Fraser

Do you have a "flat spot" when it's warmer - would a Throttle Position Sensor fault do this or similar (and simply be worse when the engine is cold?).

Dave

maybe water in a pot
cheers
blaze

Originally Posted by bblaze

maybe water in a pot
cheers
blaze

May be water in the fuel?

as frazer130 said, no fuel on over run. but mate its not a nice thing to do to your motor. cold every thing wouldn't have expanded to its correct shape, maybe oil past the rings, thats what i would put my money on. maybe the humidity being denser its taking more or any heat that there is out of the motor?

Not an easy one to diagnose via a chat forum.



The cost effective maintenance website gives some ideas of the various types of smoke from a diesel and why.



"White smoke occurs when raw diesel comes through the exhaust completely intact and unburned. Some causes of this include:

• Faulty or damaged injectors
• Incorrect injection timing (could be a worn timing gear or damaged crankshaft keyway).
• Low cylinder compression (eg caused by leaking or broken valves, piston ring sticking, cylinder and/or ring wear, or cylinder glaze)

When white smoke occurs at cold start, and then disappears as the engine warms up, the most common causes are fouling deposits around piston rings and/or cylinder glazing. "

I have worked on an old Toyota diesel where the white smoke is due to not enough diesel going into the diesel engine itself - the engine misfires as a result and unburnt fuel comes out as white smoke. When investigating this, there was also water in the diesel, which also caused white smoke, but then created the major problem of damaging the fuel pump and causing the fuel delivery problem, as it wasn't diagnosed for some time. This was on a farm vehicle that was out in the rain and no fuel conditioner was put into the tank.

However, if the engine is cold, could it be condensate from the exhaust? I'm certain that the above isn't exhaustive either!!

Thanks to all who contributed. I have noticed the yellow water light flickering intermittently @ times and thought nothing of it. It never stays on just flickers. As for flat spots it seems to be accelerating/revving as per normal. One other suggestion that I tried this morning was letting it warm up about 5 mins @ home and then driving it. Same problem, however, I have found that if I accelerate and brake at regular intervals down the hill is seems not happen. It is really funny, It happens at exactly the same place on the hill every day, regardless of speed or idling time @ home.

I will have Dorans check out the fuel system and drain some (maybe) water and try a longer warm up. failing that, an Exorcist.

Craig

Thanks to all the users that have helped me with this issue. Being the fool that I am I forget to check the most basic thing..........the air cleaner element. Changed it on saturday @ the cost of $27. Most surprised to find a spare part for a disco under a grand.........anyway...everything appears good now.