300tdi strange smoke problem, ideas?

[pete3000]

I took my 110 defender in for it's yearly MOT and was a little concerned that the smoke reading was borderline.

I noticed that the smoke only happened as the accelerator was pressed for 1 second or so. The engine pulls fine and the turbo can be heard quietly whistling on a steady incline when acc is pressed.

It was something I had noticed, visible on dark nights in rear view mirror with someone behind the landy with their headlights on.

The engine has done around 80000 miles and was a salvage unit about three years ago. To replace a 2.5 NAD It didn't do this when I first installed it.

Since then I have maintained with services at 6000 intervals. In fact the oils and filters were done before the mot.

Things I have done.

I have a paddock mushroom top snorkel which was fitted 2 years ago.

Cam belt and idler changed when installed at 69000 miles.

checked valve clearances before MOT.

cleared valve cover breather and checked pipework.

had intercooler and pipes to check for de-laminating and off turbo a small amount oil before turbo and after,but not loads. turbo impeller wheel spins freely, without wobble.

The things worrying me are the cover was missing off the fuel injection pump when I had it.

I have only adjusted the torx stud a couple of turns to back off the smoke, this made no difference to the blip of smoke though so I put it back to where it was.

I have a list of jobs to try but all vary in expense, I have considered, in order.

Injection timing, bigger intercooler(easier breathing), injectors change, new turbo, new piston rings, not really sure what else. Any ideas guys?

Pete

[western]

chuck some injector cleaner in & go for a decent length drive & make it work hard.

was the emission test done straight after your arrival at MOT place when it engine was still hot & running, or was it left to cool & shutdown ?

always best to do the test straight after arrival, my mot guy does & it's never failed.

[pete3000]

Thanks Ralph, Yup I've tried the redex diesel treatment, (the restores power one). Although I had run this through after it's MOT, didn't cure the smoke though, I put some in before it's MOT last year and have been told it does bring the readings down slightly as do changing the filters and oil.

The MOT guy put my landy on the ramps with the engine running for leak checking etc must have been idling for 5mins.

I ran it for 30 mins fairly hard down the bypass and local roads before turning up for the test also.

I don't use my landy a great deal or as a daily driver so don't want to spend thousands on it, but I would like to eliminate the initial acceleration smoke if possible. It's not blue smoke like a dead turbo or thick black like over fueling.?

there is a sooty deposit around the tailpipe but this I would think is fairly normal?

The second or so of smoke is on gear changes when re applying the throttle, or can be seen at night when driving in front of another car with headlights on. I can get it to grey smoke if I really open the throttle up to top revs in 2nd/3rd gear but this happens in most diesels if you dump fuel into them? and not something I like doing often. Watching the smoke test makes me cringe.

I was thinking the fuel injection pump had been messed with or my injectors are blocked/carboned. I'm not losing any oil or gaining any and the crankcase pressure seems normal.

Pete

[western]

as cover was missing from the injection pump sounds like the previous owner has been tweaking the pump, maybe worth having the injectors checked for correct operating/pressure & see if the pump can be reset back to standard settings.

[JimAttrill]

If you take the diaphragm out of the pump, you will be able to see marks where the shaft has been. You can easily set it back to the original factory setting which should get rid of your smoke problem. And maybe wind the star wheel about 1½ turns anti-clockwise in case that has been interfered with. After the MOT you can, of course, set it all back to how it was.