Charcoal Canister question
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Joined: Oct 2012
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From: Lucas TX
Charcoal Canister question
As I was cleaning up the engine bay on my 76, I found a cut or broken vacuum hose. I traced it back to the charcoal canister. The carb to canister hose was not there. No problem, the AIM showed me where it should go. Like all the other rubber on the car, the rubber hoses were rotten, so I decided to replace the short hose to from the hard line to the fuel tank to the canister too. The hose broke when I pulled it off from the hard line. That didn't surprise me, but I found something jammed up in the hose next to the hard line.
It is a small plastic piece with a small hole in it. It doesn't seem to be broken from anything, so I went to the AIM to see if I could find it. I could not. I saw something that looked like a valve next to the fuel tank, but my AIM is too blurry to tell exactly what it is. Was this inserted to prevent siphoning to the charcoal canister or to restrict liquid gas from getting in the vapor line? Is this all of it or is there supposed to be some sort of valve? Is the hose next to the charcoal canister where this is supposed to be? Help please, I am stumped.
It is a small plastic piece with a small hole in it. It doesn't seem to be broken from anything, so I went to the AIM to see if I could find it. I could not. I saw something that looked like a valve next to the fuel tank, but my AIM is too blurry to tell exactly what it is. Was this inserted to prevent siphoning to the charcoal canister or to restrict liquid gas from getting in the vapor line? Is this all of it or is there supposed to be some sort of valve? Is the hose next to the charcoal canister where this is supposed to be? Help please, I am stumped.
Team Owner
Joined: Sep 2006
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From: Westminster Maryland
Hi cw,
The piece of hose is supposed to have that 'restrictor' in it.
It's "original"!
The AIM shows the "seperater" that keeps the liquid gas in the tank and allows the gasoline fumes to be drawn to the vapor canister.
Regards,
Alan
The piece of hose is supposed to have that 'restrictor' in it.
It's "original"!
The AIM shows the "seperater" that keeps the liquid gas in the tank and allows the gasoline fumes to be drawn to the vapor canister.
Regards,
Alan
Last edited by Alan 71; Nov 4, 2014 at 07:15 AM.
Instructor
Joined: Jun 2014
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From: S W pa. pa
Good morning Guys I too have a 76 that has the canister unhooked. I would like to get it working again. I don't have a q jet, I have a holley carb. So, where do you hook up the vacuum line on the carb? I tried manifold vacuum teed into the pcv line but that didn't work. My canister only has 2 lines on it. 1 for vapors and 1 for vacuum. Ported vac.???
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Joined: Oct 2012
Posts: 86
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From: Lucas TX
My canister has two lines and what looks like a drain at the bottom. The PO changed out the carb for an Edelbrock. When I got it, there was an open vacuum port on the front (where the AIM indicates the line goes). I put a cap on it to get it to idle better (it did).
The ports on my canister are labeled carb and tank. I was going to connect the carb line to the vacuum port that was open on the front of the carb. I don't know exactly where it is supposed to go - maybe someone that has a 76 in better shape can show us.
Wayne
The ports on my canister are labeled carb and tank. I was going to connect the carb line to the vacuum port that was open on the front of the carb. I don't know exactly where it is supposed to go - maybe someone that has a 76 in better shape can show us.
Wayne
Le Mans Master
Joined: Oct 2002
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From: Las Vegas - Just stop perpetuating myths please.
That vapor line from the canister to carb needs to go to a "ported" vacuum line - one that enters the carb throat just above the throttle plates. If everything is in good condition - including the charcoal canister - the vapor is too rich at idle and can stall the engine. So the canister vapor enters above the shut idle position of the throttle plate where RPM will be high enough not to stall the engine with a rich mix.
I use small thin wire to probe the carb ports to find which ones enter the throat above ("ported" vacuum) and which ones enter below (direct intake vacuum) the throttle plate. Sometimes i have to use spray like carb cleaner or WD40 to see where a vac connection goes.
Good luck.
I use small thin wire to probe the carb ports to find which ones enter the throat above ("ported" vacuum) and which ones enter below (direct intake vacuum) the throttle plate. Sometimes i have to use spray like carb cleaner or WD40 to see where a vac connection goes.
Good luck.
