Ford 2600 diesel running rough, black snmoke.

[CTPhil]

I'm looking online for injectors and it very confusing. Many of the sellers list multiple crossover numbers as the right part, as in different parts but they say they will fit. Should I insist on the exact number from the Ford parts lookup?

 

[CTPhil]

Well I think I'm in trouble. I replaced the injectors, no improvement at all, it starts but barely runs. What's the next thing on the list of suspects?

Any possibility that a malfunctioning or leaking cold start manifold heater could cause problems like this?

 

[pmsmechanic]

Black smoke is one of two things. Too much fuel or not enough air. A guy can throw a lot of money at a problem only to find out it's something simple. I know you've checked your air cleaner but there could be a restriction somewhere else in the intake air flow. The fact that it will barely idle indicates more to the restricted air rather than too much fuel.

 

[CTPhil]

Black smoke is one of two things. Too much fuel or not enough air. A guy can throw a lot of money at a problem only to find out it's something simple. I know you've checked your air cleaner but there could be a restriction somewhere else in the intake air flow. The fact that it will barely idle indicates more to the restricted air rather than too much fuel.

Any suggestion on where to start on that?

 

[pmsmechanic]

Any suggestion on where to start on that?

Well one of the first things I would do is take the air cleaner off. Make sure the housing is relatively clean and start the tractor. If it now runs better then you know the restriction is before the air cleaner. If it doesn't make any difference then there is either a restriction after the air cleaner or there is some other issue.

I've seen air intakes on tractors plugged with birds nests. I've also seen mouse nests in the air filter housing. I also worked on a small diesel engine that started and ran quite well but had no power under load. It was in a small building and used to pump water for irrigation. As we were trying too figure things out I noticed that the wind was swirling the exhaust fumes back into the building. It had lots of power once the air cleaner was removed. The air filter looked reasonably clean but was plugged with diesel exhaust soot. A new air filter and a bit of an extension on the exhaust pipe and all was good. The point here is that the filter looked ok but really wasn't.

Hope I gave you a few ideas.

 

[CTPhil]

Thanks, I have had the filters off and there was a little change but now I've put a new filter on. I pulled the rubber hose off the intake manifold and there was no change. I also checked for return fuel flow (there was), and isolated the manifold heater, no change. I cracked each line fitting at the injectors in turn, diesel spurting out and a worsening in running each time. I'm not seeing any smoke coming from where it shouldn't, no strange sounds, no loss of coolant. So far I'm still stumped.

 

[pmsmechanic]

I'm getting stumped too! I would like to say check the timing but that is a fairly involved procedure. If your feeling brave you could try and advance it a bit and see what happens. Advancing is usually done by rotating the injection pump. Make sure you mark the original timing well so that you can go back to it if advancing doesn't work. Short of taking the injection pump off and having it checked out I'm running out of ideas.

 

[CTPhil]

Things I tried yesterday:

Blew air back through the tap, pulled the internal pump filter at the pump inlet, now I can't even reprime the pump.

 

[CTPhil]

I drained the fuel from the tank and replaced the tap, now I'm getting a stream from the injector bleeder, but little to the injectors.

 

[Agvg]

Any possibility that a malfunctioning or leaking cold start manifold heater could cause problems like this?

They can make problems, does it knock? Often leaking thermostart will make premature ignition because the engine sucks inn diesel with the air.