DB2 Loss of timing at high throttle - misfire

[WarWagon]

I put a used 6.5 DB2 on patch awhile back and it's not been problem free. Still needs a visible advance to have enough timing to rattle and start ok. Not as much advance as the last pump. I am using high pop injectors. (2300 I think)

Not making it through emissions this year. Also I get a jerking feeling with the TCC locked up doing about 60 MPH. Like the engine is misfireing. Worse than fishbite.

When I do a snap test, in park, I get notably slow engine acceleration and lots of white smoke. (unburned fuel.) Steady RPM test gets a misfire at 2000 RPM.

I can bring the engine up to full 3600 RPM at ~half throttle. If I add more throttle the diesel rattle goes away and the white smoke starts.

Is it possible for the Mechanical/Light Load Advance Setting(s) on a DB2 to completely kill timing to the point of misfire and white smoke?

Before install of the pump it looked like the light load screw, pushes the pin, was completely backed off. I set it to the old paint marks. Can't reach the screw with the pump on the engine. I have since set the cam ramp as delayed as possible to come on - rotated as far back as possible. This reduced the 2000 RPM misfire.

Anything else I can do with the pump on the engine: Does the pump need a rebuild or test stand calibration?

 

[Will L.]

Normally I say only info I would look for at this point is:

Relative fuel pressure during misfire.

I have seen pumps wear the rod so it only sucks at with rod in certain positions for around 25,000 miles,then it finally starts sucking air at all positions. If you can create misfire wihout load- great for diagnostics. Watch for the bubbles at that speed. If load is required, then mount a video camera. Old phone without service laying around works great.

If you are proven good on those it may be time to see a pump builder. My old guy could do some amazing diagnostics with it on the rig, but those guys are rare.
I really got to the unfortunate point of forgetting most procedures because he could do in 5 minutes what took me a few hours. And since he was being visited once a week anyways- he just took a quick look and made a tweek for free often.

Usually on the bench is where it goes for most builders.

Because I believe you individually are safe inside the governor- and know how to deal with possible run away: I think you need to pull apart governor assembly and put parts under a magnifying glass-Literally. Your governor could be walking out on threads, spring dropping tension, etc.

Make sure your main throttle shaft has no play or side movement. Pressure up the IP with engine off and work the dogsnot out of if, shaking it, etc. looking for any seeping fuel.