Diesel missfire and white smoke?

tractorsam · May 21, 2022

So first off, I have done no troubleshooting, yet. Just bought a David Brown 995. It misses and smokes white when not under a load, its really bad going down hill. Starts well. Under a load it seems to come out of it and the exhaust cleans up. The fuel filters arent old, the injection pump was supposedly rebuilt shortly before this issue occurred. No heavy breathing from the engine. Any thoughts? Im intending to set the valves and pull the injectors and test them soon. Thanks, Sam

Dieseltech · May 21, 2022

Incorrect injection pump timing can cause white smoke too. With engine off, try advancing the pump housing a bit and see if it helps. DO NOT move the pump with engine running like a distributor is done.

tractorsam · May 21, 2022

Could that cause my intermittent miss?

Bruce from Can. · May 21, 2022

I had a similar problem years back with a CaseIH 585. Started and ran smoothly, under load it would smoke white smoke, and miss and backfire through the exhaust. I had to drain the fuel tank, and blow out the fuel lines. It was starving for fuel. Sediment in the tank was blocking fuel flow. Cheap place to start trouble shooting

Dieseltech · May 21, 2022

caterpillar guy · May 22, 2022

I'm with Bruce check for fuel flow. If no fuel all the timing in the world will not fix the problem. After fuel flow is solved to the filters with new filters. Follow flow to the pump. Whether low pressure or high pressure does not matter just follow it through to injection pump. Should get a good solid flow or good free flowing rushes off a low pressure pump if it is a lever pump like a cam operated one. Once checked and good then timing can be accomplished with any satisfaction. Also take a look at the air filter. Not necessarily a problem but a very over looked item just the same. Now when running again watch for your missing and white smoke. Look at radiator for bubbles if none present probably not leaking into radiator. If coolant is low refill and check after next running and see if low again after running. This will need several hours like when mowing or tilling,plowing something to warm it up and sustain temperature for a few hours. If low you are using coolant through the engine. Lots of options there Gaskets, cracks and such.

Fritz Maurer · May 22, 2022

If it comes out of it and cleans up under load, I doubt fuel flow is a problem. Restricted fuel flow can cause white smoke in some instances, but it would never pull a load if it was starving that bad.

tractorsam · May 22, 2022

A quick update - today I had a chance to read the operators manual. It mentions a cold start screw on the injection pump, a quick inspection of the tractor showed its been in the excess fuel position the whole time. Put it to run and its like a whole new tractor. It has a paper pre-cleaner for the air which still has a DB part number on it so theres some more things to do and Ill get the fuel system and air system serviced. But so far - 95% better. Thanks, Sam

Diesel missfire and white smoke?

tractorsam

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Dieseltech

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tractorsam

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Bruce from Can.

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Dieseltech

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caterpillar guy

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Fritz Maurer

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tractorsam

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