no fuel to injectors - mk1 1.6L diesel (natural aspiration, 1984 jetta)

I hope this isn't a problem to post here. My mk1 1.6L diesel is naturally aspirated, so it's nto a TDI. I also posted this to vwvortex.com.

No fuel is pumping into the injectors, tested by removing the pump to injector line. The pump's stop valve is opening as should be. The belt is driving the fuel pump. I fed fuel by gravity into the line from fuel filter to pump, so I think this eliminates the fuel filter. Is there anything else to check first, on the pump for example, or is it time to replace the fuel pump? Thanks!

Not sure if anyone what will flame you for this, however, I feel your pain.

Air, you must eliminate air leaks before replacing the pump. I believe this is a mechanical style pump like the MK3 And early mk4 are, as is mine. So if the seals on the pump are leaking, or the lines are leaking, you'll lose prime.

We often recommend hanging fuel in a container and running the supply and return to it. This will create a gravity feed. If you have a syphon pump handy use it for the supply and pump fuel down to the pump.

After you have guaranteed fuel to the pump check to see that it pushes it with enough pressure to the injectors.

Remember, the seals and hoses can leak air before they leak fuel. Fuel molecules are larger than air. This will cause a list prime.

If you're simply losing prime, you can replace seals and hoses to cure the issue.
If the pump doesn't push the fuel with pressure after the fuel is present then it's likely you have a pump issue.

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Search a bit
https://cse.google.com/cse?q=+&cx=018097697432185261444:_idbzjdyxdm

Some results
https://forums.vwvortex.com/showthr...ny-Ideas-Why-or-What-to-Check#/topics/5866192

https://forums.vwvortex.com/showthr...-delivery-issues-please-help!#/topics/6070958

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Thanks! It won't pump when I gravity feed it fuel. So the pump inlet connector and pump seals are the only places air could be leaking in. A transparent return line would show this air coming through after cranking the starter. If no air in the return line, then no air leaks, and it must be a broken pump mechanism.

Some background would help. Did it stop running? Hasn't been run in years? ...

Maybe the internal lift pump is gummed up.

Yeah, could be as simple as pump head and o-rings. Which if anything like the VE pump can be tricky to do o-rings on...
Impossible to say without a bit more knowledge..

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It can also pull in air around the injection pump shaft seal at the pulley end if bad.

KLXD said:

Some background would help. Did it stop running? Hasn't been run in years? ...

Maybe the internal lift pump is gummed up.

Click to expand...

That is what I would want to know. If VE pumps sit for a long time, they'll get messed up. Things stick, things won't work.... even if they were working fine when the engine was stopped.

Not much to that fuel system, I use an electric inline pump to prime the system, put between the filter and the pump (this is a pain on early ones with the banjo fittings, you may need to make something to fit) and have all the delivery pipes loose at the injectors.

You can prime it and have some fuel dribbling out at the injectors that way. Then crank the engine. If the pump cannot make delivery pressure, it is shot and needs to be rebuilt.