Also known as the charcoal canister, the vapor canister is one of the core parts of your car's EVAP (evaporative emission control system). This canister is designed to collect and store fuel vapors that are emitted by the carburetor and fuel tank. A vacuum attached to the canister sucks the vapors and transports the emitted gases back into the fuel system. This way, the vapors are burned while the engine is running and are not released into the atmosphere. Once this part breaks down, you're most likely to experience these problems:
- Reduced power
- Poor fuel economy
- Fuel odor
- Rough engine handling
Vapor canister troubleahooting and maintenance
Two common causes behind the symptoms above is a crack on the canister or pipes and a dirty canister. If you suspect that a canister or hose is leaking, bring your car to a shop and have a technician run an EVAP test. In this test, the technician will put nitrogen inside the gas tank to build pressure. Once the pressure drops, it means that there is a leak. The technician will then run tests and inspections to determine which part (canister or hose) is leaking and needs replacement. Now if the culprit is a dirty canister, you can clean it at home. Here's how:
- Air compressor and air line
- Screwdriver set (flat head)
- Socket and ratchet
Step 1: Uninstall the vapor canister.
Using a screwdriver, uninstall the canister by removing the bottom and top lines. Then remove the canister from the assembly bracket with a ratchet and socket.
Step 2: Prep the air compressor.
After setting the canister aside, switch on the air compressor to let the air pressure alowly build up inside. Once the pressure reaches at least 50 psi, switch off the compressor.
Step 3: Attach the air line.
Put the rubber tip of the air line's nozzle inside the outer vent control valve pipe. This vent control tube is a bit bigger than all the other pipes and is located on top of the charcoal canister.
Step 4: Apply air into the vapor canister and pipes.
Once the air line is securely attached, cover the openings of the other pipes with your fingers while allowing the air inside the compressor to blow inside the canister. Do this for around two minutes. Next is to blow air into the control valve pipe. While blowing air, put your finger at the bottom part of the pipe, taking note if the air does come out on the other end. If it does, it means the canister is clean, allowing proper air flow from the top part to the bottom pipe.
Step 5: Reattach the vapor canister.
Reinstall everything you've removed in step 1. Make sure all the lines are securely attached to prevent vapor leaks.
When cleaning the canister, now is the best time to inspect it for signs of damage such as cracks, holes, and corrosion. If a canister is beyond repair, replace it as soon as possible because you'll most likely fail an emissions test once this part is busted.