benz,for your reference, just because an ip can be timed and appear to be functioning doesn't mean it will pump fuel, the pressure plunger that produces all the high pressure is shoved up by a cam shaft in side the pump but is returned by a spring. i have disassembled a lot of ip's that have all the plungers stuck up and you ain't going to get a drop of fuel till you get the plungers back down. this is why i mention inserting a straw so you can see the plunger move up and down. you get that motion with fuel available and you have to get small volume under high pressure.
larry perkins
71 old cars