rudolph schenker

I recently removed my old Crossfire engine and put in a new zz383. My new set up is now carburated. Do I still need the charcoal canister behind the driver grill? If not can I remove it without causing any problems? Also what did this switch do? It was connected to the canister.

TheSkunkWorks

I haven't delved into the evap canister system enough to know about the switch, but I believe keeping the system in good order would be prudent. Properly plumbed (or maybe even improperly), leaving it in shouldn't hurt performance, and taking it out and capping off the lines will require changing the gas cap to a vented type, which will then vent raw vapors.

sjmaster

Man, I need to spin some old Michael Schenker Group albums now

That vacuum switch probably controlled purging. I read that cannister purge only happens on start up.

1fastC3

i ran the line from the gas tank side of the cannister to a vac. port on the carb and bypassed the cannister all together, no troubles so far. good luck.

-alex

11Jake

I can't give you an answer on the switch. I didn't have any switch when I removed my canister and lines. I removed all the smog equipment and caped the lines on my 80 and haven’t had any problems with performance or gas smell.
Good luck!

...Roger...

Your fuel tank is vented through the canister.If you block the lines your tank will not be vented and the engine can starve for fuel and even cause the tank to collapse.

7t2vette

If you remove the cannister, you will need to seal off the connections at the tank as well as change to a vented gas cap. The vented gas caps are like one-way valves; they allow air in but not vapors out, they are this way to prevent the fuel pump from collapsing the tank. A properly functioning vapor recovery system will not affect performance in any way.

rudolph schenker

I thought I would keep the canister and line from the gas tank connected, but cap off all the other lines to the canister except the one on the bottom of the canister.

7T1vette

If you only leave the line from the tank to the cannister, there will be no "flow" passage for the system to work...it would just be dead-headed. You need to keep the line up to the engine area so the vapors in the tank can get burned by the engine.

...Roger...

but for the sake of discussion when do you think these vapors will form?When the engine is running air should be going from the canister to the tank because the engine is sucking fuel from the tank.In his case and I'm not totally sure about his pump situation he is going to have fuel returning also -churned up by his 1982 crossfire electric pump.This could create some fumes.When the car is shut off and the heat causes some expansion I would say the fumes would go to the canister.On the next start up the engine should evacuate the canister "if" still connected to the engine.

rudolph schenker

Let me clarify my fuel pump set up. Since I'm now carburated I no longer have an in-tank electric pump. I opted to run a mechanical pump, this way I don't need a pressure regulator. I capped off the return line at the tank (gas tank has been newly replaced I also removed the old fuel line and ran a new fuel line). My thoughts were to vent the tank through the existing line up to the charcoal canister, which will be open to air via the bottom hose which tucks up in the frame rale. I thought this would still allow venting of the tank and might help with a potential fuel smell?

7T1vette

Flow through the vapor system is FROM the tank TO the cannister, then INTO the engine. The cannister "collects" the vapors from the tank until the engine is running, then manifold vacuum sucks those collected vapors into the base of the carb so they can be burned off.

...Roger...

Your talking about when the engine is not running -right?

7T1vette

Any vapors in the tank can only go one way...toward the cannister. If there is some positive pressure for vapors to release [engine OFF], they go to the cannister and get "held" by the charcoal stuff. Then, with engine ON, the engine vacuum sucks the vapors back out of the activated charcoal through the base of the carb and then get burned by the engine. The cannister gets enough air flow through it to purge it before you shut it off again.

Rotonda

If you remove the canister and leave the line, it will vent the tank. As you fill the tank or the fuel in the tank heats and expands, fuel vapor will be expelled. As you pump fuel out for use ,or when the fuel cools and contracts, air will be drawn into the tank to equaloze the pressure.

Question - Why did you remove your fuel return line? The return assures that you will always be supplying cool(er) fuel to the carb, giving you more consistant mixture/performance and also go far towards preventing vapor lock.

...Roger...

Yes "but" when the engine is running the flow path is reversed.This same line allows air to flow from the canister to the tank as fuel is being removed from the tank to feed the engine.So your statement of one way flow from TANK to CANISTER is not correct.

7T1vette

I guess that I'm not certain about that one. There is a "fuel separator" on the left side of the fuel tank and I'm not sure of its involvement with pressure equalization of the fuel tank when running.