I suppose I should start getting some updates documented. I certainly haven't stopped working on it, she seems to crave constant attention over the last 1/2 a year.
I played with a bunch of stuff on the old injection pump. Talked to some shop techs and tried different things. I just couldn't get the fueling dialed in and further adjustments didn't seem to make the results I was expecting.
I played with timing using a dial this time to find out where I was. .074" of lift equaled 1.88mm which I estimate is in the 17-19 degree range. A bit more than I wanted to run but no real difference.
I played with the pressure regulator on my VE pump. The idea is to run a little more case pressure so that more fuel can make it to the high pressure piston and ultimately make it to the injectors. Too much or too little pressure can be bad. However, pressure is used to actuate the dynamic timing function in the VE pump so that plays into the tuning as well.
It has a funny head and was a bear to get out. I fashioned a socket to work but ultimately, as barbaric as it sounds, a chisel and vice grips became the norm.
The center rod on the regulator can be adjusted by driving it deeper into the bolt (adds case pressure) or tapped back out (reduces case pressure) but you have to tap the inner spring out and then tap that rod back up.
Replaced all the o-rings and put the collar back on.
So that's the fuel going in. The fuel out on the injection pump is regulated by the OUT banjo bolt via a tiny hole. It's a fixed size and not adjustable like the P-pump variants. To get a case pressure reading I drilled a port on the end of this bolt and installed a fitting that I can attach a pressure gauge for reading and a cap when I'm not. This allows you to see what pressure you are running. This was part of the conversation I had with the shop tech on playing with the pressure regulator.
I also played with the shim stack on my KSB unit that controls the dynamic timing advance function. Adding more shims would delay when the timing started to advance, thus to compensate for the added case pressure.
None of this got me what I was expecting so pulling off the injection pump for some investigation became the next step. I read the Bosch manual a couple of times and found some good VE rehab threads in the VW world with great pictures to get a clue before I opened it up. It wasn't until I pulled the distribution head off that I found one of the springs broken in two places and the drive from the cam plate to the distribution piston broken. So while I had timing and fueling "set" at a higher value, my actual timing and fueling was not producing those expectations due to the breakage. I'm really not sure how long it had been like this. It may have been this way before the compounds got set up.