I bought this 1981 Volkswagen 1.6 diesel with only 30,000 miles on it. Timed it and it ran great for a year. Drove it all the way from Idaho to Massachusetts and back. Ran fine. Then injection pump sprung a leak around the choke lever. I replaced it along with the main shaft seal and put it back in. Thats when this weird low low power thing started. So I put a used injector pump bought off ebay. Same problem. (that was over a year ago). So just recently I put in a new set of Bosch injectors from autohausaz, couldn't get it started. Bought a rebuilt injector pump from parts place inc. Same problem. Only now I noticed how fast it drinks fuel from using a gravity fed bottle (bypassing the tank). Definitely not normal consumption. And only a little white smoke. When I press the pedal its clanky and has low low power. Something is definitely not right. And I've meticulously timed it repeatedly. Checked to cam shaft timing repeatedly. Tested the voltage at the pump shutoff solenoid. Is there something I'm missing? Could it be a cracked piston or something?
I can think of a couple of things to be checking. One for sure is the compression in all 4 cylinders. You need to have about 400 psi to meet minimum specs. I think 480 is normal. So get on that first. You have to have an adapter that replaces the injector in order to do the test. Or you need a fitting that replaces the glow plugs. The injector one is the better option as getting the GP's out from behind the IP is a pain in you know what!
Then could you have advanced the cold start lever, not the choke, when you did the rebuild the first time? I am thinking you had it running already pulled out even though it didn't look that way. That would be advancing the timing and even if you thought it was spot on now it is like you are timing it with the cold start lever pulled. That would not apply to the other pumps you have purchased. Money wasted in my opinion. Never just throw dollars at a problem, find the problem then buy the parts to fix it.
So with multiple pumps, you still have a poor performer. Could be rings, could be head warp. A compression test will tell you what you need to know there.
Got clear fuel lines?
Might have put a regular banjo bolt in place of the "OUT" bolt.
Must have gotten it figured out, no reply from the NEWBIE