Hello World,

This is my first tech article post. I did try a search in google and on here but came up blank. I did find a lot of reference material regarding wiring fuel pump & Carb combination but nothing specific to AuX Air valve wire.

A bit about what I have: 1974 914 2.0 recently rebuilt into a 2056 build. I'll be using empi HPMX 40's as they came with the car but I do have a rebuilt set of italian webers to go on after the break in period. Ignition will be in the form of a Pertronix Flamethrower 009 equivalent with ignitor 1 module. Wish I could have found a mallory but they are NLA as we all know. I'm open to suggestion on an alternate dizzy choice if anyone has one that would work better than the Pertronix, but for now this is what I have to work with.

The PO had an Empi 009 points dizzy installed along with MSD 6A Model 6200 and Tach adapter model 8910 and Coil is MSD Blaster 2. I might need to change this to a Flamethrower but some people have had success using the MSD Blaster 2.

The wire for the Aux Air valve I traced from the 12 pin relay. This is spliced in with the red wire coming from the tac adapter and the red from the dizzy. (see attached) I've identified and label the wires coming from the MSD box and where there wired to. There's one yellow wire that was added and was connected to the relay board in one of the open spots in The FI 4 pole connector housing not sure why maybe someone here can explain the reasoning for this.

My understanding is I can delete the MSD and Tac adapter and wire the Black/red wire from the relay to the + on the coil and the black/purple to the - of the coil. Then wire the dizzy as per the instructions.

My question is what do I do with the white Aux Air Valve wire from the 12 pin relay board?

Click to view attachment
Click to view attachment

That wire is live, but doesn't go anywhere anymore. You need to shrink wrap it so it doesn't short on the block, blow the fuse for the fuel pump and leave you stranded on the side of the road wondering what just happened on your maiden voyage around the block.. with your wife in the car.

Yeah, ask me how I know.

To clarify, the wire is live when ever the fuel pump is powered. Needs to be safely isolated, as there said.

Thanks all, I think I can open up the 12 pin connector and remove the wire completely unless it's a bridge in the connector to power something else.

Ya I can't see that being a good thing. As is my wife says it sounds like a tractor and before the rebuild smoked like one to.

The AAR wire is a switched 12V power source. Use it for anything you want, or nothing at all.

Why don't we have more lights in our engine bays? This would be a great power source for a row of LEDs

That are only on when the fuel pump runs? That doesn't sound overly useful to me...

I would just tape the end of the wire and zip-tie it back along the harness so it's out of the way.

--DD

I think Jeff just means it's powered when the key is on (and fused through the 25 amp fuel pump fuse on the relay board) and can be used in that context.

If not used, then yes, insulate and zip tie out of the way.. or eliminate entirely back to the relay board (which seems more trouble than it's worth, imho).

I think you guys are confusing the AAR wire with the CSV. The CSV only functions under limited conditions, but the AAR is powered whenever the key is on. If it wasn't, then the AAR would be open all the time with a resulting massive idle problem. At least that's the way I remember it.

Maybe I need to go back and review the manual?

Yes, review the manual.

The AAR is spring-loaded open. When you power it, the coil heats up and closes the valve. The wire to the AAR has power when the fuel pump runs, the same circuit powers both. That's not quite the same as "when the key is on", though it isn't the worst approximation.

The CSV is closed by default. It gets power when the key is in the "start" position--while the starter is cranking only. The TTS provides a ground path for the CSV only when it is "cold enough". So the CSV only opens up when it is cold and the starter is cranking.

--DD

So for all intents and purposes, I'm right huh. In that whenever the car is running - when the engine is on and FP spinning...that AAR circuit is delivering a constant 12v that could be useful for something...like full time engine bay lights or...?

Lets not tell the bling crowd or we'll start to see purple light shows coming out of the engine bay at night to go along with their lifted 914s with 24 in rims and wheel well lights.

You're kind of inverse on what power does to the AAR, though.

--DD

Nah I got that down. Power to it heats it up and closes it.