smoky 300tdi

[tassydisco]

G'day all,

My 300tdi disco has a bit of a strange problem that has been going on for a few months now. It is quite hard to start when cold in the morning or when has been left sitting for a few days. Once the vehicle has been driven for a few minutes it starts fine. But when the engine is cold and i am coming to a stop (de-accelerating) it blows a heap of smoke, only when foot is off throttle. give it a rev and it clears, only seems to be when its cold, or when i am going down a long downhill descent in low-range. Things i have tried to fix it are, new glow plugs, new valve stem seals, and i've been running deseil conditioner through it for a while now hoping this will miraculasly solve all my problems.
Has anyone had the same problem, or have any advice for me on where to start looking? The motor only has 240kms on it, just did all timing gear in the front, and regularly service, etc. Runs really well plenty of go so i'm thinking perhaps injectors? Not sure, am a bit stumped, any advice or experiance would be muchly appreciated.
Cheers

Adam

[Blknight.aus]

check the valve adjustment and the injector pattern.

[justinc]

Timing is retarded.

JC

[tassydisco]

Thanks heaps to both of you. I will check out all these things and let you know how i go. This should keep me busy after work this week ;)
Much appreciated - Adam

[archifx]

try replacing the seals on the fuel sediment tank.

[tassydisco]

Timing is retarded.

JC

Finally got around to working on the disco today, timing was well out, so thanks heaps, while we're at it, doing the clutch,overhauling the brakes, various gasket and seals and fixing oil leaks in the gear box. Could turn out to be a bit expensive, but oh well, gotta keep it in top shape, haven't fired it up but will let you know if it goes better! :D

[gazby]

Had a cold starting problem with my '97 Tdi exactly as you described, turned out to be the Injection pump (I.P.) throttle shaft "o" ring seal.
Try this test, only of course if injection timing reset that you have just done has not fixed cold starting problem.
Make sure the fuel tank is at least 75% full, find a slope in your driveway or yard where you can park the vehicle overnight, i.e. where the rear wheels will be at least 200mm higher than the front wheels, park the vehicle with the nose facing downhill, in the morning or whenever, while the engine is cold, try starting as per normal procedure. If, as in the case of my old girl it buttons straight off what you may find, as I did, the leak at the throttle shaft was allowing fuel to siphon back to the tank via the excess fuel return line thereby loosing prime in the I.P, requiring lots of turning over of the engine first start to get fuel up in the injection system.
It seems that with the I.P. so high up on the engine any air entering the fuel side of the I.P will cause fuel to drain back to the tank which is lower, if the vehicle is parked nose up hill or on the level, particularly if the tank fuel level is low.
This test method is a good indicator of this particular problem, and if I am understanding what you describe the engine starts ok every time after, once it has had its first start of the day, that is what mine did.
New "o" ring seal is $1.00, new I.P. top cover joint ring $4.00 from any diesel injection specialist, you need a bit of mech ability and common sense to fit the bits yourself but it's not brain surgery. Good luck.

[tassydisco]

I finally have the disco back on the road! Its been a while but its never ran so well! Thanks for your help everyone makes it a lot easier to nut out.Cheers - adam