3406B injection pump timing issues

Is there any type of timing advance failure on a 3406b with the later style timing advance unit that would cause timing to be off by approximately 70 degrees

I pinned flywheel at TDC and removed plug for cam timing pin on injection pump and didn’t see slot….yes it’s at TDC number 1 cylinder because I pulled valve cover and both intake and exhaust have proper lash

So I proceeded to turn motor over approximately 70 degrees until I could see slot on fuel pump camshaft

I did mistakenly loosen 2 of the timing advance bolts prior to checking timing but with the other 2 remaining tight I wouldn’t think the timing gear slipped as I rotated motor to get it to TDC

It ran fine up until recently and driver complained of low power…I drove it and yes power is low….it acts like it’s missing….a little white smoke at idle

Any help would be appreciated to save me possible unnecessary work

 

It’s surprising to me because we have had about twenty 3406’s throughout the years and I’ve never encountered this before….but I guess there’s a first time for everything….I cracked one injection line at a time and they all seemed to cut rpm’s relatively equal except for number one cylinder….i put a reman injector in number one and no difference so then I suspected a bad plunger or something in injection pump….one thing I noticed was at idle I couldn’t really feel any pulsating on any of the injection line nuts at fuel pump except number one cylinder I feel a real distinct pulsation on number one injection line…this made me think may something up with plunger….as I began removing pump I noticed the timing issue so don’t know what to make of it all….the pump has never been serviced since truck was new in 1990 so it’s got who knows how many hours on it…hour meter and odometer have not always worked but it’s got to have at least 15 to 20 thousand hours on it

maybe I’ll just hook everything back up and retime it first and see what happens….my luck it has multiple issues