1989 GMC S15 passed smog but failed functional EVAP test.

My 1989 GMC s-15 passed all smog tests but failed fuel evaporative controls functional test. The smog technician said pass was a 40 my test was a 45 . He gave a card to and auto repair place and said the repair would cost 80 dollers. My gas cap passed. This is the first time I have seen this test. I would appreciate advice on how to proceed.

Answer:

The EVAP test is a smog check requirement. The test ensures fuel vapors are properly routed to the intake manifold and charcoal canister, and do not leak into the atmosphere. Your vehicle must pass the EVAP portion of the smog check in order to receive its smog certificate. We recommend allowing a smog check repair station to diagnose your GMC EVAP fault and make the proper repair. More then likely the repair will involve replacing a broken, cracked or brittle fuel vapor line.

posted by SmogTips Support