LT1 Carb Help Needed
Thread Starter
Instructor
Joined: Sep 2007
Posts: 101
Likes: 2
From: Cape Cod
LT1 Carb Help Needed
I hope someone out there has already solved this problem and can help me. I have a 1972 LT1 coupe that is perfectly original, smog equipment and all. I have a horrible gas fume smell and have even had gas pour out of the charcoal cannister under the left front fender. Nothing seems to be broken or obviously clogged, I have even tried vented and non vented gas caps. I think this may be part of the problem in getting the car to run or start after it has warmed up.
Any help or suggestions are greatly appreciated.
Any help or suggestions are greatly appreciated.
Team Owner
Joined: Sep 2006
Posts: 31,270
Likes: 4,362
From: Westminster Maryland
Barry,
I'm surprised fuel has gotten to the charcoal canister. It seems to me that there would have to be extreme pressure in the tank for that to occur. There is a relief valve built into the top of the tank that's supposed to stop that from happening. Also, the separator assembly mounted on the top/end of the driver's side of the tank should stop the fuel from going any further forward. If you take the separator off you should be able to hear the valve rattle when you shake the separator.
This should all be able to work with a sealed gas cap.
Do you have the GM Chassis Service Manual for your car? There is some info about this Evaporation Control System in section 8.
Regards,
Alan
I'm surprised fuel has gotten to the charcoal canister. It seems to me that there would have to be extreme pressure in the tank for that to occur. There is a relief valve built into the top of the tank that's supposed to stop that from happening. Also, the separator assembly mounted on the top/end of the driver's side of the tank should stop the fuel from going any further forward. If you take the separator off you should be able to hear the valve rattle when you shake the separator.
This should all be able to work with a sealed gas cap.
Do you have the GM Chassis Service Manual for your car? There is some info about this Evaporation Control System in section 8.
Regards,
Alan
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Sounds like the float in your carb has soaked-up fuel and is not actuating the needle valve properly. If you know that it has been replaced in the last couple of years, never mind....otherwise, get a new Nitrofil float for your carb and make sure it is set to the correct height. Might as well put in a new needle valve while you're at it.
Thread Starter
Instructor
Joined: Sep 2007
Posts: 101
Likes: 2
From: Cape Cod
Alan
Thanks
I don't have the shop book on the car. Is the valve you are speaking of on the charcoal cannister of the fuel tank?
also, do you think that this is causing the warm start problem as well??
Thanks
I don't have the shop book on the car. Is the valve you are speaking of on the charcoal cannister of the fuel tank?
also, do you think that this is causing the warm start problem as well??
Team Owner
Joined: Sep 2006
Posts: 31,270
Likes: 4,362
From: Westminster Maryland
Barry,
The relief valve is part of the fuel tank itself.
It's that little thing that looks like a "button" in the upper right corner of the photo near the tank filler neck.
About your 'warm start' I don't know, 7T1vette will be a lot more help than me!
Get the FACTORY Service Manual for your car it's worth the $ many times over.
Regards,
Alan
The relief valve is part of the fuel tank itself.
It's that little thing that looks like a "button" in the upper right corner of the photo near the tank filler neck.
About your 'warm start' I don't know, 7T1vette will be a lot more help than me!
Get the FACTORY Service Manual for your car it's worth the $ many times over.
Regards,
Alan
