I adjusted the injection pump in my 84 300D just yesterday, for the first time. It was very difficult to get at 2 of the 4 nut/bolts.

The rack position sensor is in the way for the top-right nut. I had to spend a lot of time to get just the right combination of sockets and extensions to get my 3/8" socket wrench into the narrow gap where you can swing it, just aft of the sensor. I also had to jam a screwdriver against the extension to hold if for the clicks.

The aft bolt (below vac shut-off valve) was tricky because I had to swing a wrench in the small gap between the oil cooler tubes. I used a Craftsman 13 mm ratcheting box wrench that has fine clicks. I was able to loosen the bolt, barely getting the next click. But in tightening, I had to remove the wrench each time and turn the head manually for the next click, which took a long time.

I adjusted the IP on my 85 300D a month ago, and recall it being much easier. That car has an 82 engine, which doesn't have the rack position sensor. That sensor is only used for the EGR controls, which I bypassed anyway.

I never fooled with making a "drip tube", as shown in the manual. I just remove the #1 fitting on the pump. Before "start of delivery", the fuel squirts out, as you pump the primer. The "start of delivery" is where the flow gets blocked. It is a pretty sharp point, changing from squirt to nothing in ~1 deg of crank rotation. The 1 drip/sec is probably an anal spec the writers had to put in to quantify the process. I set both cars to 27.5 deg BTDC. Both were at ~24 deg BTDC as found, which is the factory spec. Both timing chains showed no stretch per the camshaft mark.

I can't say I really noticed a change in the way the engines run. Indeed, I found 3 injectors in my 84 engine were non-turbo (popped at 1600 psig), but it runs about the same now with 5 turbo injectors (1950 psig pop). Both engines shake a little at idle, and smooth out at higher rpm.