327_TPI_77_Maro

iTrader: (8)

hi guys, I am still figuring out small details of vac routing on a V8 CCC qjet car that I am assembling, using all correct emissions provisions, on a 1983 Firebird that was originally V6. The V6 setup uses a vacuum purge solenoid, near the vapor canister on the driver's side fender. Does the V8 use this solenoid at all, or does the purge control valve connected to the Qjet control purge without needing the electric solenoid? The vac purge solenoid has 2 ports -- 1 connects to a vac pod on the vapor canister, and the other port connects to a vacuum source. My question is, what is the vac source (if the V8 needs this solenoid at all)? Is it a timed (ported) vac. source from one of the front ports on the Qjet (if so, which letter port), or is it simply full manifold vacuum that I can connect to the tree coming off the rear of the carb, which power brakes also interface with? Thanks!

Vader

There was no solenoid on Federal emissions level cars. California cars may have been different, but they don't count.

The 1983 LG4 and L69 used a timed port on the carburetor to feed a TVS on the intake. This purge valve signal was fed from the TVS through a purge control valve (a form of a vacuum differential valve) that would only allow purge if the overall engine vacuum (sampled at the PCV valve) was above a given point. The system was such that when the engine had reached a given temperature and the throttle was opened beyond a given point, and engine vacuum was above a set point, the EVAP canister would purge.

327_TPI_77_Maro

iTrader: (8)

Vader, I just checked several manuals and even wiring diagrams, they show that the Fed V6 had a purge solenoid (mine did) but none of the Fed V8s did. It looks like my stupid vapor canister set up for the purge solenoid has too many ports to use with the V8's purge control valve, so I'll have to go grab a V8 can at the junkyard tomorrow.

99Hawk120

Correct, you need a V8 carb canister if you have the one with the solenoid built onto the canister. I did that on my '84.

327_TPI_77_Maro

iTrader: (8)

The solenoid is not built into the canister, it is external. however I don't know what to connect in place of where the solenoid would go on a V6, in the case of the V8

99Hawk120

I'm going from memory here, but I am pretty sure it's the line that goes to the carb. The other line, the one from the fuel tank, needs to be open at all times.

1991L98G92

If the wiring for the purge solonoid is still in use (I would think if your going from V6 to V8 there would be computer issues) the purge connector on the carb would be center front base plate just below the fuel filter housing. If solonoid is removed, get the V8 cannister. Here's a vacuum diagram: