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torquefoot February 27th, 2017 10:09

1.6TD IP will not draw fuel but runs fine on gravity
Hey guys,

I have a thread on but thought I'd chime in here.

1984 mk1 Jetta with newer motor, I believe its code MF from an '89.

Basically after changing some seals on a leaky IP (shaft seal, main seal, cold start seal, pressure valve o-rings) my pump will not draw fuel but runs when gravity fed.

Everything has been timed properly and checked twice and basically the motor runs fine when fed through a funnel but does not produce any vacuum to draw fuel. It wont even pull fuel from a bottle right next to it. Similarly, it does not push anything out through the return side.

Notes: Return bolt orifice is clear, no visible leaks on the pump, I can pull fuel easily from the IP return with a MityVac when hooked up to the bottle or the main tank with fuel filter connected, etc.

I'm waiting for some Diesel Purge now so I can soak the pump - the latest suggestion is that one of the 'vanes' might be stuck and a good soak for a few days might clear it.

If this doesnt work I have no choice but to open up the IP (which I've never done) or replace it (which I cant afford). For what its worth I have all the tools and am pretty hands on mechanically (have rebuilt carbs and a few motorcycle engines before).

Any insights are appreciated.

Bless your souls.

primerisgood March 1st, 2017 05:34

FWIW, if you need to be driving car, and as a work-around, my understanding is that an inexpensive electric aftermarket fuel pump installed in fuel line nr. tank to supply diesel under low pressure to intake of IP works, I'm pretty sure I read about it on these pages. (Google is your friend here?)
Others may have had specific experience with this.
In my own experience messing with lake-water potable water pumps, a slight vacuum leak in a 'suck' line is very hard to trace. The same line when pressurized with fluid may not leak. Eventually traced just such a vacuum leak by installing section of clear line, could see vacuum creating and sucking bubbles instead of fluid phase.
Good luck.

igiveup March 1st, 2017 18:10

I've had some hard start problems with those engines after doing work on them. (long time ago)

I had a '90 TD Golf that would not start for the life of me.

Finally what did it. I loosened off the big nut that holds the injector lines to the injector. Tied a rope to the car and had a friend pull me around the block (key in the on position). It was very obvious that fuel was flowing, pissing everywhere.

Tightened back the nuts and gave it another pull and it fired right up.

You have 12V at the stop solenoid?

torquefoot March 2nd, 2017 09:46

Primer: I appreciate the suggestion but if theres an issue with the IP that has stopped it from drawing fuel, I'd like to resolve it.

IG: What do you think the issue was? I've primed my IP many times but it just wont draw its own fuel. I can even drive the car around when gravity feeding it from a bottle but it just wont draw fuel like it used to before I resealed it.

torquefoot September 1st, 2017 09:36

Just to update this: the timing belt was too tight and damaged the internal fuel pump inside the injection pump. IP had to be replaced.

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