I replaced my fuel cap with a Fram. (red cap with a push button on the top)
The rubber seal was getting a little brittle on the old one so I replaced it but I was told that the Fram one I put on is non-venting.
I checked Rockauto.com and there was no less than 15 different caps offered!

What is the right and best cap to use??

Thanks, Kit (86 GT)

My guess.... Since the Fiero has a vapor canister for gas fumes I would think the non-vented one would be correct.

Or it might need to vent one way. IE allow air into the tank but not allow it to go out. Since the tank thas four lines, Fill, pump out, fuel return, and vent to canister if the canister would not allow air back to the tank you would need a vent one way.

I can't remember if the canister would allow leak back or not.

Most likely all the hoses are old enough there are probably enough leaks there should be no problem.

[This message has been edited by Dodgerunner (edited 07-07-2006).]

Kitskaboodle, Are you wondering because of smog test or emissions in your area? If so the local emission place will usually have the info required on your year , make, model, ect. If not worried about that I would go with what Dodgerunner is saying.

Non-venting is the only cap ever used on Fieros. The charcoal canister setup catches the fuel vapors and allows you to burn them for power, as opposed to the vented systems which allowed that $3/gallon gas to just evaporate away.

JazzMan

quote Originally posted by 3800superfast: Kitskaboodle, Are you wondering because of smog test or emissions in your area? If so the local emission place will usually have the info required on your year , make, model, ect. If not worried about that I would go with what Dodgerunner is saying.

The reason I ask is because two weird things happened to my car when gassing it up coming back from Westfest. After pulling into the gas station, I unscrewed the fuel door and as I did I heard a tremendous Hisssssss....After this I topped off the tank till it was full and then proceeded to put the gas nozzle back on the pump. As I turned around, fuel started coming back out of the filler neck! I quickly put the fuel cap back on. I dont recall my car ever doing either one of these things....

Kit

AC Delco #12F1P

The gas cap on a Fiero is one-way vented. It allows air to be drawn in, but doesn't allow any air / fumes to escape.

When the system is working correctly, any vacuum is relieved by the gas cap. Any pressure is relieved through the charcoal canister. You should never encounter any "hissing" when you loosen the gas cap.

It is possible under some conditions to have the tank "burp" some fuel out when fueling. If you're filling using a sealed fuel nozzle and pumping gas at a fast rate, pressure can build up faster than the charcoal canister can release it. Then when you break the seal at the nozzle it can "burp" and shoot some fuel back out. It's not common to find pumps set to deliver fuel this quickly, but it's always a good idea when using nozzles with that rubber bootie on them to pause after it clicks off, then remove the nozzle slowly. The pause gives the canister a chance to bleed off the pressure...