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Charcoal canister for MGB
mgb281 - 22/6/23 at 09:39 AM

I am gradually restoring my MGB and want to add a charcoal canister to stop the smell of petrol fumes in the garage. Installing one is not the problem it’s what is the best way to control the purge valve.

JAG - 22/6/23 at 12:49 PM

I had a system like that on my MX-5 engine.

The system is connected with plastic tube between the main components, like this...

Fuel Tank -> Carbon-Cannister -> Purge Valve -> Intake Manifold

I think the Purge valve is closed with ignition-off and opens with ignition-on. So a simple 12v Solenoid I guess.

When you start the engine the vapour in the Carbon cannister is drawn into the intake manifold.

Mr Whippy - 22/6/23 at 01:07 PM

quote:
Originally posted by mgb281
I am gradually restoring my MGB and want to add a charcoal canister to stop the smell of petrol fumes in the garage. Installing one is not the problem it’s what is the best way to control the purge valve.


Even my old car does not make the garage smell even slightly of petrol. Are you sure you don't have a fuel leak!

mgb281 - 22/6/23 at 02:12 PM

quote:
Originally posted by JAG
I had a system like that on my MX-5 engine.

The system is connected with plastic tube between the main components, like this...

Fuel Tank -> Carbon-Cannister -> Purge Valve -> Intake Manifold

I think the Purge valve is closed with ignition-off and opens with ignition-on. So a simple 12v Solenoid I guess.

When you start the engine the vapour in the Carbon cannister is drawn into the intake manifold.


I know exactly how they are plumber in but I needed to know how to activate the purge valve, just connecting it to the ignition switch will cause all sorts of problems, it’s like having a vacuum leak on the manifold. I suspect it is triggered by a high vacuum on over run triggering the ECU but need confirmation




Even my old car does not make the garage smell even slightly of petrol. Are you sure you don't have a fuel leak!
No mechanicals fitted yet, just pre emoting a possible problem and helping the atmosphere a minuscule amount.

nick205 - 22/6/23 at 02:42 PM

My carb'd Pinto engined MK Indy didn't make the garage smell of petrol.

Benefit that my driveway sloped away from the garage door so I started the engine and drove straight out. Left the car roadsie while closing the the garage door.

As Mr Whippy say I'd check it over for any leaks and to make sure everything is plumbed in correctly.

mgb281 - 22/6/23 at 07:32 PM

quote:
Originally posted by nick205
My carb'd Pinto engined MK Indy didn't make the garage smell of petrol.

Benefit that my driveway sloped away from the garage door so I started the engine and drove straight out. Left the car roadsie while closing the the garage door.

As Mr Whippy say I'd check it over for any leaks and to make sure everything is plumbed in correctly.


As I said in my last post neither the engine or fuel tank is finally fitted yet, there are no leaks or smell of petrol because the tank isn’t fitted. All I want to know is how to trigger the purge valve without upsetting the ECU by creating a continuous air leak via the carbon canister.

Mr Whippy - 23/6/23 at 06:16 AM

quote:
Originally posted by mgb281
quote:
Originally posted by nick205
My carb'd Pinto engined MK Indy didn't make the garage smell of petrol.

Benefit that my driveway sloped away from the garage door so I started the engine and drove straight out. Left the car roadsie while closing the the garage door.

As Mr Whippy say I'd check it over for any leaks and to make sure everything is plumbed in correctly.


As I said in my last post neither the engine or fuel tank is finally fitted yet, there are no leaks or smell of petrol because the tank isn’t fitted. All I want to know is how to trigger the purge valve without upsetting the ECU by creating a continuous air leak via the carbon canister.


That's good, just making sure your car doesn't burn to the ground...

JAG - 23/6/23 at 11:50 AM

I'd also like to say that your car will run just fine with a permanent atmospheric vent - it's kinda how engines work

It will be fine with the Purge Valve permanently open. So long as the carburettor/injection is calibrated correctly it won't make any difference at all.

Just saying