07 Impala P0442 EVAP small leak. VIN 2G1WB55K779254969
Vehicle came in with P0442 code stored. Vehicle has a 1/2 tank fuel. Removed line from purge solenoid (no service port) and smoke tested system untill smoke came out of filler tube then put fuel cap on. No smoke seen and no leak under pressure. Removed smoke and sealed system and no drop in fuel tank pressure pid. Performed purge/seal test with verdict and there was a slow drop in vacuum according to fuel tank pressure pid. Pinched off hose to vent valve to eliminate valve, still a slow drop in vacuum. Vacuum tested purge solenoid, ok. Applied vacuum with a hand held pump to system at purge solenoid line and monitored fuel tan pressure pid and still showed drop in vacuum. Have a fuel cap (GM) on order and ordered a blue point universal fuel filler adapter to smoke test from the tube to see if a leak can be found that way. Seen Bob's post and others on smoke testing from the filler neck. Wondering if the roll over valve in the filler tube could let smoke out of the top of filler tube untill the cap is installed then it would seal under pressure and not be able to detect a leaking cap or crack filler neck like the post that Bob nicely illistrated.
Thanks
Darren
Vehicle came in with P0442 code stored. Vehicle has a 1/2 tank fuel. Removed line from purge solenoid (no service port) and smoke tested system untill smoke came out of filler tube then put fuel cap on. No smoke seen and no leak under pressure. Removed smoke and sealed system and no drop in fuel tank pressure pid. Performed purge/seal test with verdict and there was a slow drop in vacuum according to fuel tank pressure pid. Pinched off hose to vent valve to eliminate valve, still a slow drop in vacuum. Vacuum tested purge solenoid, ok. Applied vacuum with a hand held pump to system at purge solenoid line and monitored fuel tan pressure pid and still showed drop in vacuum. Have a fuel cap (GM) on order and ordered a blue point universal fuel filler adapter to smoke test from the tube to see if a leak can be found that way. Seen Bob's post and others on smoke testing from the filler neck. Wondering if the roll over valve in the filler tube could let smoke out of the top of filler tube untill the cap is installed then it would seal under pressure and not be able to detect a leaking cap or crack filler neck like the post that Bob nicely illistrated.
Thanks
Darren
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