Fuel cutoff solenoid...issues...possibly

[RabbitGTDguy]

So, having some fun working through a few things on the mTDI here. I'm thinking that I may have a bad fuel cutoff solenoid...but correct me if I'm wrong...

K...here goes... when the solenoid if mounted in the pump, in the "OFF" position, the fuel stop hangs down in the hydraulic head blocking the spill port for fuel to flow. When power is applied to the terminal top + it is ground on the sides of the solenoid - and from there at the pump. When in the "ON" position, the solenoid creates a magnetic field and should pull the fuel stop UP INTO the solenoid itself, which then opens the spill port for fuel to flow.

Now...tested one of two probably pretty old solenoids that I had here tonight. The other is in the mTDI pump currently... anyways. used a 10amp setting on my battery charger. Connected power to the top of the solenoid (terminal +) and the ground to the side of the solenoid (screw portion -). Had the solenoid laying on its side with the fuel stop installed with spring, etc. Applied power and it SHOT the fuel stop and spring out of the solenoid vs. pulling it up in...

Did I miss something? Or is it too late for me to be typing? I thought it should pull it up in  

Joe

[RabbitGTDguy]

I will go down and try it again without the spring...however...
I have a 24v one from the 4bt pump here from before I had even started with the mTDI pump. Of course...it wouldn't work under 12v but the design of the valve is a bit different than the one used in the VW pumps.

The fuel stop is the same design...however, it is all one piece as the stop does not get removed from the solenoid on removal from the pump. There is no spring/stop that comes out from it. The valve would have to operate as said... (Off, drops in... ON, stop gets pulled up). To me, it seems like a simpler/newer design...maybe the new ones are even that way...but anyways, I'll test and find out...

Joe

[RabbitGTDguy]

Well...for fun...I went back at it this afternoon in testing the solenoids. It can be done via the battery charger. Maybe not the preferred way for some...but for the future, if anyone wants to test out of the car, here is how...

Simple...

I attached the positive to the top of the solenoid terminal, the negative cable to the threaded portion of the solenoid. I then stuck the fuel stop and spring inside the solenoid...

Turned the charger on and "ta-da", it worked... didn't "shoot" the spring/stop out of the solenoid as it did before when I was just apply power and briefly touching the solenoid with the negative cable...

Very simple way to test it. Glad to say, that both my units are in good condition and the "starting" problem I had turned out to be something else entirely...but, I learned something in the process...

Oh, and libbybapa ... we are right in our though. When testing and power was applied correctly the solenoid pulls both the stop and the spring up into the solenoid housing.

Joe