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So I'v isolated an issue with my car sputtering to my gas tank not venting properly. I heard people drill small holes in the gas cap to vent it. can this cause any issues?
You mean besides gas sloshing out the fuel door every time you turn right? What's wrong with your factory vent system? Is it disconnected and capped off, or is it clogged or crushed under the car?
You mean besides gas sloshing out the fuel door every time you turn right? What's wrong with your factory vent system? Is it disconnected and capped off, or is it clogged or crushed under the car?
i have a 79 , there is no charcoal canister , i have a charcoal lid
Got it. Wait, you have another thread going about this don't you? So what's wrong with your tank vent line that runs under the car and goes to the charcoal lid? If you changed carbs or got rid of the rat's nest that's okay, you just need to re-run the vent line. Without a vent your tank can't breath, and your pump won't be able to draw fuel out, because a vacuum is created (sucking noise when you open the cap). Another symptom would be pressure/fumes escaping when you open the cap, on a hot day.
These are some quick pics of my '85's vent system. The factory metal vent line runs under the car next to the supply and return lines, and up onto the firewall right behind the oil filter. It's the lowest, smallest metal line...
It runs along the firewall over to the pass side, then into a rubber hose to the charcoal can. I imagine your rubber hose used to go to the air filter, but my FB went to this stock can...
(It's the smaller, lower rubber line)
The gas tank can breath in and out all day long through the charcoal can. The bottom has holes stamped in it, and a filter media so "air" can flow in and out as needed to adjust tank pressure, but the charcoal inside traps the gas vapors and there's no unpleasant gas smell.
When the car is running that top hose draws the trapped gas vapor over to a nipple on the center iron, next to the oil fill tube...
and then it's sucked out, through the hose on the oil fill tube, and up to my filter. On the stock car it went through a timed purge valve on the rat's nest, but my rats nest is removed. My simplified setup has the same effect though - the intake draws from the oil tube, which pulls vapors from both the crankcase and the charcoal can.
I think you can plumb your metal tank vent straight into the nipple on your center iron, and then connect the nipple on the oil fill tube over to your air filter like mine....
I have a 79 as well with an aftermarket carb and no rat's nest. I added a charcoal canister pulled from a later rx-7 but basically any without a check valve will work. I have mine routed as above, it works. Also, no more condensation in the oil either.
03-10-21, 04:55 PM
