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  1. #1

    Default EVAP System?????

    Need help with finding out why I am getting too much pressure in the tank. When I open the gas cap I get and feel air pressure escaping. Can anyone tell me what the problem is? Fuel line look fine, EVAP system seems to be working. This is for a 1991 Suburban 350 TBI 5.7.

  2. #2


    I thought that was normal. Mine does it, so do all my other fuel injected vehicles, of course only after the ignition has been turned on and the fuel pump has created pressure in the system. IIRC, most fuel injected systems need something like 35-45 psi.

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