Alright first i just wanna say I have a 87 firebird with a 305(lg4) & 700r4 trans. So I passed emissions the other day and was so excited the first thing I did when I got home was rip it all out and throw my long tube hedders on. Well I jumped into it a little too fast. I later did a search and found out that the canister in the corner is for fuel vapors, so my first question is should I cap off the fuel line going back to the tank and get a vapor release gas cap? How should I go about this matter? The next thing I did was cap off anything that had emissions going to it. My carb has about 6 different caps on it. Shoud they all be capped or do some need to be left open for air to escape? My car starts and runs but I have to keep giving it gas to keep it alive. Its like I have a vacumm leak some where, but I know everything is capped off. I also already threw all my emission stuff out, so putting something back in is not an option. Thanks

 

I removed my canister, so at the gas tank, there are 4 lines,


1) fuel to engine
2) return line
3) canister line
4) pressure blow off

I think this is right, kbroenger (?) posted this before, you could find it I imagine... anyway, the #3 is what you're interested in. You could cap it at the tank (or anywhere inbetween), and run a vented gas cap, but some people say that gives off gasoline fumes. My choice was to put on a cheapo fuel filter on that line, and let it hang at the tank.

you should definately cap all the lines.

still the stock cc-qjet? with stock dist right?
you've kept your pcv right?
what about your EGR? gone?

 

Did you keep the PCV and MAP sensor?

 

Yes it is still the stock cc-qjet. Still kept the pcv. The egr is still there untill I get a new intake, but it isnt hooked up. The EGR is capped off. Would I put a cheap fuel filter on the line in the engine bay, or disconnect it from the tank and put the filter there?

 

Kept the PCV, not sure if I kept the MAP sensor. Where is the MAP sensor?

 

I would put it at the gas tank area. There are 4 rubber lines forward of your gas tank, (the flex lines).
Just chop the one in question, and cram a cheapo import vehicle plastic fuel filter on it, and use a hose clamp if desired.

 

Sorry not sure if I see the difference between putting a filter there or putting on a vented gas cap. wont they both allow vapors to escape the same? It seems easier and less work to just change caps. Please let me know if i'm not seeing something here. Thanks

 

well do whatever you like, I just put the filter on the line, since I was dropping the tank anyway, and I didn't want to put any extra gizmos in the engine compartment.

*shrug* someone mentioned that the gas cap led to fumes. Gasoline vapors tend to...float or sink in air? I'm not sure, but if they sink, starting them closer to the ground would lead them to be less noticeable.

I think your ECM, takes sensor readings, then gives signals to the mixture control solenoid, etc. So I have no idea what emissions its *needs* to work right. I ditched my cc carb a while ago.

 

Sonix thanks for the help. Also I just check to find out where the MAP sensor is. I just went out to my car and noticed it was unpluged. I also rember is having a line going from it to a sensor in the thermostat housing. I have that sensor capped of. Do i need to run thta line back? Im guessing I do. Also the sensor has to spots for the line to connect to. Does it connect to the top or bottom one?

 

well for my car i just yanked the box out and caped the lines i think there where 2. then some guy looked at it and said that shouldnt my caped so i took it and and now the lines on the drivers side just sit there open.

 

Hooked the MAP sensor back up and ran a new vacum to the sensor and the car runs great. Good call on the MAP sensor, Thanks