I just had to replace the injector pump on my 81 Rabbit diesel. Motor has a true 95K on it, but the pump was leaking from sitting so much and wouldn't draw fuel from the tank... it would draw from a glass jar under the hood and run fine, but the pump would empty onto the ground over night. I replaced with a tested, rebuilt pump... meaning it ran on another motor to verify the rebuild was done correctly. I've worked on VW's extensively in my younger years but never actually had to replace a pump (done timing adjustments more times than I can count), which is what I hope is throwing me off here:
I can't determine if I am truly TDC on the flywheel. Every VW diesel I've owned has had different markings. Some have been an actual 0, some have been a nub, some have been a raised line, etc. I am "guessing" on this flywheel that the little V groove that has the line down the center is what I should be lining up with the pointer? That's where I have it now.... cam locked, pump locked (and not 180° off) and at the assumed TDC on the flywheel. I can turn the motor by hand with all locks removed and there's no interference or weird feelings.
Back at TDC, inserted the dial gauge, rolled the motor back till the needle stopped moving, zeroed it it and turned the motor back to TDC. Once again, I am confused. I have the pump to the full advance position, yet can only get the needle up to .40mm. Not sure how to get it up to .86-.95 if I am out of adjustment.
I have noticed the needle moves more than I remember when rotating the motor backward until it stops moving... seems like it's rolling back 2 or 3 mm. Meaning the needle spins around the dial at least twice in this process.
My question being: with a new pump install, should I put the pump in the full retard position to start with the dial gauge?... or just a random spot in the middle?... or am I totally missing something?
I tried to start it and was willing to time by ear, but the motor won't start. It turns over evenly, hops and coughs like it's cold, getting smoke out the exhaust, but won't actually start and run. After several attempts, I can turn the flywheel to the assumed TDC mark and everything lines up, so not concerned that I'm off a tooth anywhere.
I am getting fuel (and yes, using fresh diesel)... can crack the fuel lines, crank and get fuel out of them so again verifying the pump is working.
Any thoughts? Thanks in advance!