Gas Tank Vacuum - ZR-1 Net Registry Forums

Mystic ZR-1 · 05-26-2016

Seems like there's a lot more vacuum then normal
when removing the gas cap? 1990 w/40k miles

No codes, runs fine. Always has passed emissions where they check
gas cap as part of check.
Fuel level in tank makes no difference.
None of the hoses/wiring etc have ever been messed with.
Just replaced fuel pumps, but it did this previously.
Gas cap?
Evap cannister solenoid valve?
Imagination?

05-26-2016	#1
Mystic ZR-1 Join Date: Jan 2010 Location: Mystic CT Posts: 2,625	Gas Tank Vacuum Seems like there's a lot more vacuum then normal when removing the gas cap? 1990 w/40k miles No codes, runs fine. Always has passed emissions where they check gas cap as part of check. Fuel level in tank makes no difference. None of the hoses/wiring etc have ever been messed with. Just replaced fuel pumps, but it did this previously. Gas cap? Evap cannister solenoid valve? Imagination?