Hello all!

Does anyone know how to route the charcoal canister on a 914 that’s LS swapped? I have most of the connections routed, I just need know where to route the hose that went to the stock 914 engine fan.

Would it be better to remove the charcoal canister entirely?

Removing the charcoal canister is never a good idea. You will end up with the smell of gas in the car, and it is not good for the environment.

The charcoal canister system on the 914 is simple because it can take advantage of the engine fan to push the fuel vapor to the air cleaner. A Chevy charcoal canister system has a "purge valve" that controls the vapor recovery. Before computers, the purge valve was vacuum operated, and was triggered by a ported vacuum connection. When the vacuum went away (the engine was not at idle), the purge valve opened and allowed engine vacuum to pull in the vapors from the charcoal canister. Later computer controlled cars use the ECU to open the purge valve.

Click to view attachment

You need an early Chevy purge valve, and it needs to be hooked up correctly to the engine. The part number is "Standard Ignition Products CP109"

Clay

I noticed the diagram you attached is for a carbureted engine. I’m running a fuel injection system. I’m assuming one end on the charcoal canister gets routed to the purge valve, then into the throttle body, and the other end of the charcoal canister just stays open to atmosphere?

I've also seen modern cars with fan connection disconnected, so the only hose to worry about is the one to the expansion tank on the fuel tank and the one to the air cleaner.

On FI, you need a purge valve that can be controlled by the ECU. One connection will go to the canister line that originally connected to the air cleaner, and the other side of the purge valve will need to connect to manifold vacuum. the other side of the charcoal canister will need to either attach to the air filter assembly, or have a small air filter put on it.

Clay

Understood! Thank you very much for the help Clay.

If you are using the GM efi, it should already have the wiring for the purge valve.

Clay

Sadly I am not. I am using the Holley Terminator ECU.

I do have one more quick question for you. Should the purge valve be routed into the manifold before or after the MAP/IAT sensor? Or does it not matter?

Here's a link to the Holly forum on how to wire your purge solenoid. https://forums.holley.com/showthread.php?15...e-Valve-Control