Over the years, if there is any one thing everyone did in my shop, it's break the distributor shaft in the pump head.. Sure, you feel dumb as a rock, but the point is, to work the pump still attached to the engine is just begging for trouble. Each of the screws that hold the head onto the body of the pump should be turned equally, because when you hear that high metallic 'PING!', its your glass-hard distributor shaft turning into 2 pieces... $400 down the drain.
Just sticking in another pump head onto the body is not the answer. The stroke for the mainshaft to the distributor shaft for the spacer shim, come in measurements of .05mm, if I recall correctly and just because you get a pump head with a shim doesn't mean it fits your body. The thing about Bosch is they used to make the old pumps so you had a setting for stroke at .039" (1mm) and that's just about what it still is.
The other day, one of my less skilled customers lost the shim and asked me to send him one. After trying to get through to him that 'some shim' isn't going to work, and then insulting me with some stuff about just trying to work him to get pump business, I don't have much sympathy left for him.
If you can't get it done, find someone who can. If you break parts, yes, there are a ton of pumps out there, in all sorts of varying shape. Some good, some not so good. Good luck.
As for priming pumps, the technique offered here is painfully slow in my book. With all fittings tightened, remove the return fuel line from the #4 injector, attach a vacuum source and draw vacuum until fuel comes up the #4 return line. The idea is that the VE pump is actually nothing more than a reservoir. Once you get enough fuel to submerge the pump head, it will flow fuel into the distributor shaft. For speed, we use an electric vacuum pump, attached to a reservoir. You don't want to pull fuel into your vacuum pump.
If there is any single problem with restarting a pump that has been reset, it's that moving the IQ body too far to the timing belt side of the engine will keep the engine from getting enough fuel to start. Also, it is better that the timing be advanced and the fuel IQ number be low. You can make and engine start with too much fuel and advanced timing. Not enough fuel and retarded timing, not so much... Another tip... removing your glow plugs will cause two things to happen. Your engine will spin much faster and you can actually tell if your injectors are fueling, because mist will come out the glow plug hole. The other benefit, if you have VCDS, the engine will turn fast enough you can get some idea of injection timing and IQ.
Another thing about the guy who needed a shim... after working for hours with him, and this all done without VCDS (please don't waste your time doing that...) he tells me after all my wasted efforts, it was the crank sensor that was bad. Instead of wasting hours of my time, VCDS would have found that in literally seconds. "Bad Crank Sensor". Or, as the adage goes, "Common Sense is, unfortunately, entirely too uncommon."
