ratter,
ok i found some other info about troubleshooting problems and they deal with low power issues and black or dark gray smoke.
They describe the possible causes as being:
- not enough air for combustion so check the air filter and make sure it is not clogged up, you should be able to pull it out and put it up to a bright light like the sun and see light through it. If not then replace it.

Black or Dark gray smoke
- injector nozzles (we already mentioned this)
they could have bad seal washers or could even be the incorrect ones. a possibility if they were rebuilt and he was just given the wrong ones back, hard to say.
- wrong fuel injection timing (we've already mentioned this and will check later).

Low power issues
- low quality fuel
- fuel pressure is low
- air in the fuel system
- accelerator linkage not adjusted properly
- wrong valve lash set on valves
- fuel injection nozzle defective (already mentioned above)
- fuel injection pump timing not correct (already mentioned above)

Now with all this said we can make many assumptions here that he did not do anything with the accelerator adjustments other than the connection at the fuel injector pump where the linkage connects. The only problem that would occur if the linkage was not connected correctly is not pulling the injection pump to full open which would cause it not to go to full rpm and cause a low power scenario but will not cause black or gray smoke. (we will assume the black smoke problem is causing low power issues for the moment).

So we go to the injectors and pump, we can check to see if there is any air in the system.
The fuel system air bleeding proceedure is as follows:
- Bleeding air from the fuel filter:
1- make sure there is enough fuel in the tank and it is clean.
2-On the fuel filter assy look on top of it, there should be a priming pump button and also a bleeder screw off to the side somewhere, you can pump the primer button to pressurize the lines and crack that screw, if you get any air bubbles out of it then let it run out till all the air is gone and clean fuel only is running out of it. Then tighten the bleeder back.
3- look on the fuel injection pump, there should be a vent screw on top of the body, use the same proceedure as bleeding the fuel filter, use the priming pump to pressureize the system till you get a good resistance on the priming pump, then crack the bleeder screw on the pump body and let fuel run out, if any bubbles let it run out till the bubbles are gone. You may have to continue to pump the primer pump to achieve this.
note: if this fuel system has an electric fuel lock solenoid on it you will have to use the preheat button till the light goes out, then turn on the ignition switch and leave it on so the fuel will flow, otherwise you will not get any fuel flow to remove any air. If you find any wires hooked to a solenoid on the fuel injector pump this procedure will need to be done to bleed air from the pump.

4- remove air from injector lines:
loosen nuts on top of all the injectors, move/press the accelerator pedal to full throttle position, turn the engine over with the starter motor until fuel runs out from injector lines with no bubbles. Once the air stops coming out of a line you can tighten the nut on that injector and do this for all other injectors as the air stops coming out. If you do not get any air out of any injector then tighten all nuts and stop cranking the engine over.

This is the order for bleeding air from the fuel system.

Now before you start bleeding air out you may want to do the following:
pull out each injector and check for the following, each injector has 2 washers at the base where they mate up to the engine head, there should be a large copper sealing washer and down inside where the injector seats into the head there should be a smaller thin steel sealing washer. Make sure all injectors have both of these. Do only one injector at a time so you will not mix these washers up, they should stay with their respective injectors as they have already been seated to their mating surfaces. If any of them look damaged or compressed wrong replace them.

to be continued on next post