Engine/Transmission (1994 - 1998) Black Smoke Continues

[Mr. Cummins]

Perhaps some of you remeber my condition... My recently purchased truck is putting out alot of black smoke. its even smoking at idle. The concensus seems to say -adjust the star wheel. The previous owner told me he had bigger injectors put in as well as a differemt fuel pump cam. Should I investigate any other issues before jumping right into adjusting this star wheel -checking proper operation of the pump, etc. How should the start wheel be adjusted if that is the suggested route to take.



THANKS

 

[Howard Durand]

It sounds to me like your engine is having trouble breathing.

Has anything been done to increase the boost and exhaust handling capabilities of your engine to complement the injector and cam plate upgrades?



If you want to try it, adjusting the star wheel can reduce the black smoke you see during acceleration.



It is inside the AFC housing located at the rear end of the injection pump.

To access it you have to remove a large round plug that is about 1" in diameter located on top of the AFC housing.

It is removed with a 5/16" allen wrench. The plug has a metal sealing washer to watch for when you romove it.

Once the plug is removed, you will see a toothed wheel inside the housing that can be rotated using a fairly large screwdriver as a lever.

To reduce the fueling and the black smoke, the top of the wheel must be rotated toward you away from the engine.

You should feel a definite click for each notch of the wheel.

Try adjusting 10 or 15 clicks at a time and see if there is any improvement.

It is a good idea to keep a record of the number of clicks and the direction you move it each time so you can go back to where it was when you started if necessary.

As you rotate the weel toward you it will move laterally toward the rear of the housing. Conversely, if you move it away from you toward the engine it will travel toward the front of the housing.

Notice where it is when you remove the plug. If it is very far forward near the edge of the hole it has probably been adjusted by someone for increased fueling.

Bear in mind that as you reduce the fueling and it's associated black smoke you will also notice loss of low end response and acceleration.



I hope this helps, I have moved my star wheel back and forth several times to get the response I want without generating too large of a black cloud.

 

[fox]

You most likely have a dripping injector. It could be an air flow-plugged air filter- issue, but if it is smoking at idle I bet it won't go down the road very well.

Does it run rough? Like it is missing?

What state are you in?

Is the timing correct? Des it clatter like other 12 valve cummins?

The star wheel shouldn't have any effect it idle.