On an 83 rabbit TD that I am playing around with, the injection pump suddenly stopped working. Earlier in the day, the governor seemed to have a few issues with idle stablization; it would rev a bit higher just so, then come back to 800rpm, then repeat. In addtion, if you revved the engine a bit, the idle would fall like normal, but drop all the way down to maybe 500rpm or so, then increase to 800 rpm along with the bespoke idle flutter.
When the pump finally stopped, the car was cold, and within 1 minute, the power dropped a bit. Then, whilst coming to a stop sign, the motor would not restart. I cracked the filter outlet banjo (we added an inline fuel pump to the car) and fuel flowed well/normally. Then I cracked the pump inlet, then outlet. All released fuel as normal, i.e. TONS of fuel. The fuel filter is 1 month old, and from the tests, is flowing very well. However, when I cracked the injector line at the injector, ZERO fuel came out. I checked each line, all were the same, no fuel.
Upon draining the fuel filter, we think someone tossed in some red wine (no joke) into the tank, as a good amount came out. While we have not verified the substance, it smells like red wine believe it or not. Damn saboteurs!
The fuel stop solenoid was verifed in function, and I even went as far as removing the fuel stop/piston itself then, reinstalled the solenoid. Same thing, no fuel being injected. I also tested if fuel flowed out from the solenoid with the fuel pump on, and it flowed very well. No restrictions. In addition, with the plunger nut removed, fuel also flows well out of the plunger/dial indicator hole.
Ok, so I pulled the injector lines, then checked the output at the delivery valves. Nothing. So, then I popped off one of the d-valves... now fuel was being injected! It seemed to change just slightly with no *throttle* compared to floored. So, I placed the d-valve back on the pump and tried cranking again. Nothing. WTF! It is like there is not enough pressure to crack open even the d-valves! It seems like there is some fundamental restriction, or something is seriously effed up.
What would break inside the injection pump? Or be restricted in this way? It is almost like the fuel sleeve is nearly totally covering the plunger intake, but as far as I could see, the governor, fuel advance etc mechanism is operational. Hours before the car died, the power was totally normal, save for the weird idle. It is almost like when the car cooled down fully, maybe something congealed? I could also see the cam plate; it looked totally normal.
Last, we tried feeding the pump straight ATF, which the internal vane pump, happily sucked into the pump (no electric fuel pump to assist). Same situation as before, except this time the fuel return discharged the red fluid of the ATF, as well as the d-valves when removed. Same thing as above!
I am about to pull the pump, or pull the head to see whats up. Any advice is appreciated!
Update: Checked pump stroke and timing. Both are dead on.
That is really weird... I've never heard of this happening before. It almost sounds like the governor mechanism broke or failed. Usually these pumps are quite bullet-proof... doubly weird! Done any mods to the governor? Maybe that oddball fuel you drained from that filter stuck, galled or damaged the governor or high-pressure section of the pump? Wish I could provide more help but never before have had, or even heard of such a problem. Good luck,
One other thought... you sure the pump is primed before you're cranking it over? If it's not primed, and air is in the system, no fuel comes out of the delivery valves. But it does seem like you have tested that by observing fuel coming out of the stop solenoid. OK, maybe disregard this. :?
Thanks for the tips Jake. Yah, this is VERY weird, I've never experienced this behavior either. I think I might have a look deeper into the control collar / fuel control mechanism, as maybe it somehow disconnected(?) from the main fuel lever. As far as the governor springs, they are changed, but operate properly as far as I can tell, and they feel the same when you operate the fuel *throttle* lever with your hand.
It is almost as if the control collar is not moving, therefor limiting nearly 100% of any fuel being injected, save for when the d-valves are off. Or there is some blockage at the control collar. Not sure :cry:
Perhaps Giles would have some answers? I am open to any suggestions!