Every time I turn the key to "on" position in my van, I hear the fuel pump run 1 sec, shuts off 1 sec, then runs 1 sec again. This is of course to build the pressure in the fuel system, or to prime, as you put it. This cycle is of course automatic, and should be controlled by a relay or the ECU. I guess there is a small error on your bus
that makes the prime switch necessary. What that error may be, I do not know, I do not know the aircooled injection system at all.

PerL
87 Syncro 112i

David wrote:

> A previous owner installed a 'fuel primer' button on the dash of my 82 vangon.  You push it and hear the wine of the pump and then a bit of a gurggle and then you let go of the button and start the engine and it starts fine.  If you don't push the button it takes a loooong time to get it to start.  So your asking, what's the problem?
>
> The problem is, why does it now need a button to start the fuel pump to get the fuel up to pressure and it didn't when the vehicle was new?  BTW it has a GD000861 engine, or an early 2.0L found in the 76-78 BUS.  Perhaps they had fuel pump prime buttons in 76???
>
> My purpose is to find and fix the original problem that caused someone to install a fuel priming switch.
>
> Thanks,
> David