N109 Shutoff solenoid for marine applications

I've got a VW TDI 140-5 (ANH engine type) which is essentially the same engine as used in the Transporter T4 and similar vehicles. The fuel injection pump solenoid is physically identical to that used in cars, but the functionality is reversed - meaning that when power is OFF it allows fuel to flow but when it gets a +12V signal it shuts down the fuel supply.

I believe that my solenoid needs replacing, but since VW has sold this engine to Mercury/Mercruiser I need to go through their ordering system and they want $580 for the solenoid, plus it is back-ordered. Considering this 10x markup I am unwilling to get their part but am looking for alternate sources.

Does anyone here know where I might source this part? Who makes the OEM part? Are there after-market manufacturers that I might contact?

Do you have a part number or manufacturer name? I don’t know if this helps you or not, but in the past I’ve looked up sensors and switches by function on a Echlin’s site. They have descriptions such as normally open versus normally closed, Voltage ranges, resistant ranges etc.
Not that I think you would necessarily find it there, but searching manufacturers sites in that way may lead you somewhere

No, I don't have a manufacturer name; I was hoping someone here might know who manufactures the standard solenoid used in VW GTIs so that I might be able to locate the part that way. I assume it is Bosch but I couldn't find anything on the web relating to a normally open rather than normally closed variant.

So, get a reverse signal relay and get the other part and solve this issue the right way for your wallet. That's bs btw

Can you email Bosch tech dept? Frans at Dutch Auto, Darkside, or another European supplier may have a better handle on it

Solenoid, not delay his request reads

Relay

you could make a relay for what you want to do.. or should be able too.

Zanshin said:

The fuel injection pump solenoid is physically identical to that used in cars, but the functionality is reversed - meaning that when power is OFF it allows fuel to flow but when it gets a +12V signal it shuts down the fuel supply.

Click to expand...

Interesting to know this exists... it would be cool to swap this part into a mechanical pump VW diesel to have an engine that can run even with a major electrical failure, e.g. for an expedition vehicle. A relay could easily invert the signal to integrate with the existing wiring.

Well, the issue has now become somewhat of a moot point. I won't need to change out the solenoid after all! After weeks of trustration getting this marine engine to run, today was my first successful day in quite while. Jesse, the diesel expert from Banchwerks, came by with my old fuel pump and we went to work.
We removed the marine solenoid from my original fuel pump.

and put it back into the engine. Unfortunately, the RPMs were still erratic and we couldn't find a logical explanation for the engine's behaviour. We were brainstorming and looking at the old solenoid when it hit both of us at the same time - there was something missing.
We were torn between looking for a mechanical problem or an electrical one. We measured the cable resistances and tested relays and I wanted to put the car solenoid without the blocking valve into the engine to test the always-on mechanical situation. This takes a while to do, since you have to remove all the cables to the ECU box, then get the box out, access the solenoid and then put everything back together.
Once we'd done that the engine fired up, but the RPMs were far too high and we had to adjust both the timing chain and use the VW TDI "Hammer Mod" to get the fuel quantity back into the correct range. Once that was done the engine ran perfectly!
So what was causing our issue with a solenoid installed? it could still be an electrical issue in the wiring loom that wouldn't let the solenoid work correctly; but somehow that didn't seem correct...
finally the solution hit us at the same time and the following picture explains the problem and solution:

It turns out that the previous mechanics in the BVI had removed the uncaptured spring from the solenoid when they re-installed it. The spring was in the plastic tray that contained all the screws and bits-and-bobs that we'd removed from the engine in order to access the important pieces!

Glad you found that!