I was wondering on the TBI, if there is vacum going from the TBI to evap canister.
The line I have going from TBI to the canister does not have vacum. It only has a bit of fuel, but thats it. I've heard that there is vacum that goes to the canister, but unplugging that line just leaves me with a bit of fuel around the TBI opening and no change in the RPM. Just wanna know if there is vacum to the canister or not!!
Can you go without it??? I've searched on this but none of the answers made sense.

Thanks.

Laters.

 

The hose you are talking about is a purge line to suck the fuel vapors from the tank to the manifold to be burnt. There isn't vacuum on it at all times, as far as I can tell. Judging from the location on the throttle body, it looks to be ported vacuum. Some GM applications use a purge solenoid to release the vapor from the canister to the engine. My particular application doesn't use a solenoid.

Personally, I'd leave it on. Doesn't cost power, and it keeps fuel vapors from being released into the atmosphere. Plus, it's the only way to vent the gas tank. No vent, you could starve the motor for fuel.

Tim sends

 

Hmmm. I wonder if those canister dudes go bad?!?! I think I might replace mine!

 

I had one rot out on my old Suburban. Passed tailpipe sniffer, but still had to retest after I replaced the canister.