Club 80-90 Forums

Please excuse the basic question but Diesels are still black magic to me!  Petrol makes so much more sense!

After lots of starting and running issue finally traced back to air leaks (I think) It now starts stops and drives fine.  But....

The stop solenoid on the fuel pump does nothing when power is connected to it. It looks ceased. I presume it has been creatively engineered like the rest of the install.  Despite this the engine runs very well.

My question is why does the engine stop when I turn off the ignition is there a valve somewhere else?

There is wiring and a relay to the old style fuel filter housing that I have yet to identify.  Anyone?

 

Maybe not the stop solenoid then.

The stop solenoid (#8 on the pic above) on the pump should make a small click when you touch the +ve onto the stud and another when you remove the power. If the engine runs and stops, then it is working correctly (or there is another shutoff solenoid somewhere inline the fuel lines).
The relay and wiring on the filter could be a prewarmer. Maybe PO ran on Waste Wegetable Oil (WVO). A pic would help to identify it.

Are you sure you're not looking at a waxstat on the side of the pump? This is a cold start advance device, which won't click as it only has a heater element in it, and even when powered it wouldn't be apparent that it's doing anything.

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The wax stat on the side for the advance seems to be working ok although it does not move far.

The stop solenoid has no visible movement or noise when removed and connected to power. As far as i can see there is nothing else in the fuel system.  Is there an air shut off in the inlet somewhere to shut the engine down? or is it always fuel on VW's.

I have ordered a new fuel pump solenoid just in case.  I am keen to learn as very few garages deal with anything this old round these parts.

studog wrote: ↑31 Mar 2022, 11:33 The stop solenoid has no visible movement or noise when removed and connected to power. As far as i can see there is nothing else in the fuel system.  Is there an air shut off in the inlet somewhere to shut the engine down? or is it always fuel on VW's.

It is always fuel on VWs.
The solenoid itself does not move. Just pulls a plunger inside the pump.

Ok thanks. 

I am very confused by this as the solenoid is different internally to that one and there is a loose piston and return spring inside the pump.  If anything the pin in the solenoid would push this further into the pump.  But the pin does not move when the solenoid is removed and connected to power.  Yet the engine stops instantly when I turn off the ignition.
I will return it to the factory setup as illustrated.