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Evaporation System problem

For a few months now, my check engine light has been on in my '03 chevy cavalier. The scan says its an evaporation system malfunction. Well I was reading the car talk desk calender for thursday april 15th, and you said that filling up your gas past when the pump automatically shuts off can damage or break the vapor recovery canister. Well, just about every time I fill up I put a few more dollars in to make an even dollar amount. Could this be why my check engine light is on? and Where the heck is this canister?

Probably. The canister is located at the right front fender on most Cavaliers. Some, I have heard, are near the gas tank. Overfilling the gas tank will allow raw gas to get into the charcoal canister which can damage it to the point of replacement.

It could be. Your gas tank breaths in and out through a bed of activated charcoal in the charcoal canister. In some vehicles overfilling can cause gas to gett into the bed and saturate the charcoal. Since the tank cannot breath through a saturated bed, the EVAP system registers this as ab inappropriate vacuum and trips the CEL.

However, there are other things that can cause an EVAP light to trip. A bad purge valve, a bad purge solenoid, and others. And they can trip different codes. Don’t make assumptions. Post the actual codes here and we’ll try to help.

I agree with mountainbike that it is possible that the problem lies in a purge solenoid/ valve rather than in the carbon canister, but in the meantime, may I suggest that the OP stop overfilling the gas tank?

I’m hooked on paying at the pump with a card. I can let it stop at the first click. No rounding up and no growing coin collection.

Yup
If someone pays for his/her gas with a credit card (or even a debit card), there is no need to “round it up” to the next dollar.

If someone is about to set out on a drive across the Gobi Desert, I can understand wanting to force that extra bit of gas into the tank, but for those of us who drive on paved roads in the US, the next gas station is usually not very far away–thus making that click-click-click-click process a very expensive practice in the long run.

It can be. Unfortunately the OP seems to have made the assumption that the canister was the problem and moved on. I hope he/she didn’t just assume it was the canister and spend the money based on that assumption.

I have not done anything yet. I was wanting to check here first to see what people thought. After reading that article a light popped up in my head. I thought that seemed like a pretty logical connection, seeing that I go past the auto shut off all the time. I usually pay cash at the pump, but maybe its time to move on with the card. I know that its not cheap to have the system tested, so I thought by maybe taking the chance to replace this part I can save a lot of time and money. But its a gamble, and if I loose I could be down a lot more $