Some how (only when above a 2/3 tank of fuel) my car runs rich. First instinct i drop the tank to check the pressure relief valve on the top of the tank.. There was no such valve. Second i'm thinking the valve is on the charcoal canister. i have yet to find out where it is. If anyone knows what might cause this and or where the canister is, the help would be much appreciated.

also i have found that there are also 2 other possibilities. 1. A shut off valve for the charcoal canister inline before the canister. 2. that the valve is actually a part of the fuel pump in which case i would have to change the pump. again any ideas would be appreciated.

thanks

 

Why are you thinking the car runs rich? Is it throwing a code? You have black smoke coming out the tail pipe? Mileage is bad? You just think so?

 

Mileage is bad, exhaust smells rich and is black but not very excessive, and runs rough. as an example it runs like a carbureted car would if your jets were to large. it is throwing 5 codes one of which is for the evap the rest all could be caused by that. things like random miss, system lean (oxygen sensor), ect. that is why i'm pointing the finger at the evap system. wouldn't be the first time i was wrong though.

 

List the codes you pulled, not the system affected.

 

Like kwatt said, list your codes please.

You may need other stuff fixed too, but your symptoms point to EVAP system not functioning properly; most likely Evap valve stuck open.