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Hi Bz,
I believe what you found is the hard line from the gas tank vapor control system that included the canister at the left side apron.; not part of a return from the carb to the tank.
I don't know if you can use it for the purpose you're considering or not.
Regards,
Alan
I was thinking this was used to vent from the old vapor canister back to the gas tank. The fuel command center must vent back to tank so I was hoping to just plug into this existing line since the FCC will be in the old vapor can location.
Thanks for the help Alan. I found a good forum post that answers alot of my questions. Really excited about this Fitech unit. Can't wait to get her in.
Last edited by Bloodzone; Nov 9, 2016 at 05:04 PM.
I was thinking this was used to vent from the old vapor canister back to the gas tank. The fuel command center must vent back to tank so I was hoping to just plug into this existing line since the FCC will be in the old vapor can location.
Thanks for the help Alan. I found a good forum post that answers alot of my questions. Really excited about this Fitech unit. Can't wait to get her in.
I believe the line you refer to is the vent that goes from the tank vapor / liquid separator to the canister. I don't know if you can use that, but if you do I think you would need to reroute it to bypass the separator / check valve.
Hi Bz,
The system was called 'Evaporative Emissions Control'. All GM cars had this system beginning in the 1971 model year.
It's purpose was to have the engine burn fumes being given off by the gas in the tank and not have it released into the air as happens with an unsealed gas tank.
The engine's vacuum pulled the fumes from the tank to the canister and then on to the carburetor where they mixed with the fuel charge and were burned.
Regards,
Alan
Bloodzone,
Good morning, I'm not very familiar with the unit you are planning to install. But I am very familiar with that steel line you are asking about. Just as Alan mentioned, it is the fuel vapor line from the tank " Fuel Separator Check Valve" up to the EVAP Caninster which you no longer have on your car, ( note:the 79 may not have a check valve though, not positive on this, I thought they stopped with the 74s !) Alan also explained it's function as intended. These were used on sealed gas tanks. ( The gas cap will say " SEALED" open slowly/ carefully. ) You mention that your steel line was blocked, that must mean a PO replaced your gas cap with a vented one??
After reading your link above it appears that that gentleman ran the fuel line from the fuel pump to the CC and the from the CC with a HP line to the carb. I don't think you'll be able to use the car's fuel vapor line for your installation. Just my opinion!
Regards,
Jimmy
it appears that that gentleman ran the fuel line from the fuel pump to the CC and the from the CC with a HP line to the carb.
Thats exactly what I plan on doing. I only want to use that steel line as a vapor return to my fuel tank from the fuel command center. The CC must be vented back to tank so I was hoping to use the line because its already there. A check valve would complicate things.
Thats exactly what I plan on doing. I only want to use that steel line as a vapor return to my fuel tank from the fuel command center. The CC must be vented back to tank so I was hoping to use the line because its already there. A check valve would complicate things.
Your correct about my cap it is vented.
If the line was plugged up front, follow it back along the frame making sure it's ok, then up to the tank. Remove your spare tire tub and the plastic spare top under the tank so you can see where/ how that line is connected back there on the tank. Tough to see up in there. If it is still connected as original back there,( I'm not sure what's back there on a 79)maybe you could disconnect a hose connected to it, so it's no longer connected to the tank and try blowing some air through it from the front, and have someone back there feel to see if it comes through, then you'll at least know the steel line isn't blocked. Just a suggestion.
So, then the CC does take the place of the charcoal canister? If everything is still connected as original back at the tank and the line is clear, once reconnected to the CC you would think it would be ok. You would think there is something back there that keeps the fuel from traveling back up through that line. Especially if that's what the instructions say should be connected on a 79 as far as fuel venting goes. Then, does it say you'll need to switch back to the sealed gas cap?
Best of luck?
Jimmy
So, then the CC does take the place of the charcoal canister?
Its not intended to replace it. But my canister has already been removed and the FCC fits the space prefect so that part of the install is a no brainer.
Thanks for taking the time to help me out with this. Your recommendations are pretty much spot on with my plan.
I will still need a vented gas cap. Because after everything is installed the vapor will be traveling back to my tank and will need to vent thru cap.
It's been a long time since I did this - But I believe that I used that line as a return for my Holley once (it's a 1979) - But I would follow the line back and verify anyway.
Its not intended to replace it. But my canister has already been removed and the FCC fits the space prefect so that part of the install is a no brainer.
Thanks for taking the time to help me out with this. Your recommendations are pretty much spot on with my plan.
I will still need a vented gas cap. Because after everything is installed the vapor will be traveling back to my tank and will need to vent thru cap.
Your welcome. Keep us updated on the project.
Inquiring minds want to know
Jimmy
I've had no major problems. Any issues were tuned out with handheld controller.
Canister vapor return line works great, just use a vented gas cap or another tank vent method.
Car starts right up like a modern car,outside temp does not matter.
MPG slightly better.
Throttle response is much better. Tires will break loose at half throttle if you punch it
Make sure you have the system setup for the fuel command center and not a inline pump. It comes default to inline pump and will overheat and shut off after hour or so of driving. Ask me how I know hehe.
Other than that, very happy with mine.
1 other thing, car runs smoother and I believe a little quieter. It dont wake the wife as much.
Last edited by Bloodzone; Feb 9, 2017 at 03:38 PM.
Can you describe or post a picture of how you routed the lines from the FCC to the throttle body? Curious about how people approached fuel line routing in case I ever go this route.
If you mount the FCC in the vapor can location its really easy. I just routed it up over the brakebooster into right into the throttle body. Really clean looking.
The line from the mechcanical to the FCC could be a bigger issue. I run a electric fan so mounting line right to the frame in front of engine was easy.
Last edited by Bloodzone; Feb 9, 2017 at 06:38 PM.
Can you describe or post a picture of how you routed the lines from the FCC to the throttle body? Curious about how people approached fuel line routing in case I ever go this route.
I have not purchased the system yet. I have really been researching as much as possible to avoid any pitfalls when the time comes. I am currently running a Summit 600 square bore,vacuum sec. and electric choke. With a 1" spacer on a Weiand Action+ and it really has done a super job. With very little tuning it run great out of the box. I have been concerned about plumbing the vapor vent from the FCC, which fitech says must be returned to the tank. Thankfully, Bloodzone clarified what I thought about "T"ing into the existing vapor to tank return. As I have discovered, the '79 did not have check valves or a vapor/fuel separator. I'm not 100% sure where to locate the FCC yet because of being focused on the vapor return. I'll post updates,thanks.
If you mount the FCC in the vapor can location its really easy. I just routed it up over the brakebooster into right into the throttle body. Really clean looking.
The line from the mechcanical to the FCC could be a bigger issue. I run a electric fan so mounting line right to the frame in front of engine was easy.
Great pictures, Bloodzone. As if I needed more ideas what I can do under the hood. I am running a electric fan also, and I thought that would be the practical way to run the line to the FCC from the mechanical pump. Also looks like I found where to put the FCC also. I really can say that is by far the sharpest underhood I have seen. I can really appreciate what you have done. WOW! Do you have a quarter mile run on it? Thanks again for the pictures. And advice. And ideas for projects!
I'm a little slow on the typing but I'll get there eventually!
Fitech install vapor return question
