Q: Evap Monitor not ready

asked by on May 13, 2017

Hi. On my car the evap monitor has not been wanting to clear. I just recently failed smog due to bad cat. I changed the cat, the Canister Vent Solenoid, Canister Purge Solenoid, Charcoal Canister, Fuel cap & MAP sensor. The car runs a little rough right now but no check engine light. I know its a EVAP problem because i recently cleared the codes before and it keeps coming back. As of now no light is on, runs rough and only monitor needed to clear is the EVAP. I need to do the smog but not sure if i can still get it done with the one uncleared monitor in CA. Any suggestions? thank you also car has a fairly new engine little less than 20,000 miles on it.

My car has 20000 miles.
My car has an automatic transmission.

Hi There, It sounds like you have replaced and checked all the normal suspects in the evap system. You may also want to check the lines in the evap system. A leak in the system may also cause the code to be triggered and the motor to run rough. When an air leak is present in the EVAP system, the MAP sensor will not be able to determine the air density, and the MAF sensor will not be able to determine the volume of air, entering the engine correctly. This will lead to an over fueling situation or an under fueling situation depending on the size of the air leak and engine operating speeds and load. This may eventually lead to catalytic converter problems as well as misfiring problems. I would recommend having an expert from Your Mechanic come to your location to diagnose and inspect your vehicle.

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