Check Valve On Fuel Regulator Vac Hose

[cashmgr]

Hello All,

I have a 1988 Grand Am Quad 4 LD2. A vacuum hose routing diagram that I have shows a "check valve" on the vacuum hose that runs from the intake manifold to the fuel pressure regulator. My engine just has the hose (it was replaced at some time, not by me).

Should I locate the proper check valve and replace it? Is this a critical item for the regulator/vacuum system? Also, the fitting on the regulator for the vac hose is a different size than the fitting on the manifold - this suggests to me that some kind of regulator or reducer was probably intended to be there.

It seems to run ok (a little rough at idle - but common for the earliest quads). Your thoughts, part #'s etc. are greatly appreciated....

Thanks

[GTP Dad]

If the car runs alright then I wouldn't worry about the check valve. The valve is probably there to prevent fuel from being sucked into the engine should the pressure regulator diaphragm fail. If you want to replace it then search rock-auto.com or gmpartsdirect.com as they should have the part available.