I replaced my ECM with the Fast EFI 2.0. I took my EVAP can out thinking it would be ok but I’m getting tired of the fumes and I’d like to get it working again. Is there a way to do this? I thought the solenoid was controlled by the ECM?

 

Hello Michael,

First, the disclaimer;

I have no clue if my idea will work or not, it was just a thought I had when I read your post.

Cars in the 1970s had charcoal cannisters/ EVAP systems, with no ECM to control them. Maybe you can look into how 1970s cars did their EVAP systems without an ECM and copy that? I'm pretty sure it involved some sort of TVS (thermal vacuum switch) and perhaps other non electronic controls to purge the EVAP can at the right time.......

 

Yes. I am runing it with no ECM. of course the electric solenoid is eliminated...

 

So how does it work? Is there any kind of valve? I’ve heard that if you don’t have a valve you’ll be sucking raw fuel into the canister.

 

Early evap used thermostatically controlled vacuum switch. Circa late 70'S cars. Try rock auto. Might get lucky.

 

The original vacuum-operated valve is retained. Like Orangebird said; you need to utilize a thermal vacuum switch (TVS). There should already be one unless someone removed it.
That prevents vapors from being sucked in before the engine reaches a certain temperature (or maybe it's after -- can't remember). The only difference is that your ECM will no longer be monitoring the EVAP system. Cars prior to 1981 had these systems with no ECM. Thirdgens distributed only in Canada did as well (at least the early ones). An EVAP diagram for Canadian thirdgens may be of help to you...

 

Vacuum Diagrams - Potential Sticky? - Third Generation F-Body Message Boards

 

Early TBI trucks and vans did not use a purge valve of any kind. Just a vacuum hose from the canister to ported vacuum on the TBI unit.