Thread: That ledgendary puff of smoke on start up 300tdi.

Hi all,

The Bosch VE distributor pump is designed to put out maximum fuel on start-up. In the governor there's a very light spring that holds the control collar at the maximum position when the engine is stopped. So, when you begin cranking, it injects the maximum fuel charge. As soon as the pump is doing a couple of hundred rpm, this start-up spring is fully compressed and pay no further part in proceedings and the idle spring comes into play to regulate the idle speed.

Originally Posted by llandro

However, I have found that by applying a touch of accellerator as I turn the key, the annoying puff is much lessened.

Have to dig out the diagrams again to confirm but it seems pretty likely that touching the accelerator would probably also override the start-up spring and set the governor for a "just above idle" fuel setting, hence avoiding the max delivery "puff". Should work well with a warm engine (I'll try it later today) but might not work so well on really cold mornings though.

Originally Posted by Rayngie

I had mine parked down in Manly last weekend, just by an outside restaurant, started it up, gave everyone a lung full, who all turned and sent a few choice words my way, what do they expect?, they are having lunch on a footpath, next to a road, where cars park, and expect not to smell cars???

weird....

Maybe tell 'em that only homeless people eat on the footpath .

The day we picked up our new 1997 Defer we proudly took it my Mum & Dad's place for them to see.

When we were leaving my missus was putting the kids in the rear seats with the back door open. I thought it would be good to fire up the beast (Landy) and let it warm up a bit.

That was fine but a huge cloud of black smelly diesel covered the wife. She was not amused but the kids loved it .

Needless to say she hated it from then on and now I don't have it anymore, the Defer I mean .

mine used to do it, but i fixed that problem......

Timing belt...
if the timing is out a Bees Faaarrrr-t then it does the smoke on start, if its set right it is almost non existant.....

Originally Posted by Leo109

Hi all,

The Bosch VE distributor pump is designed to put out maximum fuel on start-up. In the governor there's a very light spring that holds the control collar at the maximum position when the engine is stopped. So, when you begin cranking, it injects the maximum fuel charge. As soon as the pump is doing a couple of hundred rpm, this start-up spring is fully compressed and pay no further part in proceedings and the idle spring comes into play to regulate the idle speed.

Have to dig out the diagrams again to confirm but it seems pretty likely that touching the accelerator would probably also override the start-up spring and set the governor for a "just above idle" fuel setting, hence avoiding the max delivery "puff". Should work well with a warm engine (I'll try it later today) but might not work so well on really cold mornings though.

I'll save you the effort.

It only over rides once the pump is spinning even if its too slow for the govenor side of business to be doing its thing.

which is why you still get the puff as the first few turns will be at max fuel setting then when the RPMs get high enough for the throttle side of the control to take over they take over even if the engines not at idling speed yet.

The govenor generally is only there to regulate fuel at the idle throttle position and I think its also reposnable for overall maximum RPM fuel control. (but that Bit ID have to look up as well.)

The black smoke thing is worsened by the fact that the first couple of injections may not be fast enough or hard enough into hot enough air to get a start as the starter motor is still trying to wind the crank up to speed (lets pick a really bad enigne that just doesnt want to play) so when it does finally fire its not only got the fuel that was injected to burn off (which will be too much in its own rights cause its a full noise type injection) but all the fuel from the previous firings.

as an interesting side its hypotetically possable to crank over some diesel engines for so long without it starting (lets say you had a starter that just wasnt spinning the engine fast enough to reach the ignition temp) that you will hydraulic a cylinder with the injected fuel.

I have found double glowing can cut the smoke on startup.

Originally Posted by sumo

No mufflers??? Chit! that would scare me . How come?

Sumo.

after a bit of reseach i removed them as part of the injector pump tweak to get max gain

I once started the Defender for some reason at a camp ground and my co-drive had tied her swag off one of those little bars on the crossmember. With the airventy on the swag open it was perfectly lined up to cop a great load full of black smoke right into her swag.

She was not amused. My rejoinder that I could not see the problem, as she was not in the swag at the time, seemd to make her even lass amused.