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

torquefoot

Veteran Member
Joined
Dec 5, 2009
Location
Toronto
TDI
1990 Jetta 1.6TD
Hey guys,

I have a thread on vediesel.net 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

Well-known member
Joined
Jan 27, 2005
Location
Sudbury, Ontario
TDI
1992 Jetta TD with 1984 Rabbit TD engine, 2nd '92 original engine, '90 Jetta TD GL
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

Veteran Member
Joined
May 2, 2010
Location
Mississauga, Ontario
TDI
2005 Passat, 2009 Jetta
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

Veteran Member
Joined
Dec 5, 2009
Location
Toronto
TDI
1990 Jetta 1.6TD
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

Veteran Member
Joined
Dec 5, 2009
Location
Toronto
TDI
1990 Jetta 1.6TD
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.
 

Z1Turbocat

New member
Joined
Feb 17, 2021
Location
Parker, Colorado USA
TDI
ADE & CKRA
Did you ever find the fix for this? I'm having the same issue after having a loose fuel filter that was sucking air into the fuel with the engine in my snow cat, a 1999 TDI 1.9 ADE. Anyone out there know how to get the pump to start drawing fuel on it's own?
 
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