I have a 2000 Rodeo that was burned when a gas pump overflowed and static set the blaze. The Rodeo has been repaired and runs well but I had a crazy CEL. My mechanic found a vacuum leak on a part but we nor the local Isuzu dealers know what the part is for. It is a black plastic housing that was attached to the filler neck of the fuel tank. It has an in and out for vacuum lines. It is a box roughly 2 1/2 inches by 1 1/2 inches with some kind of valve and no electrical connection. We by passed the "thing" and the car still runs fine. Any help in determining what it is would be much appreciated. I know it has a use or it would not be there.

sounds like something for the evaporative emissions system, doesn't it.
you should be able to find it at the official isuzu online parts site
http://www.myisuzuparts.com/

i'll look later but can't now

let us know

//bc

Thanks, I have taken a look at the parts site and cannot find this component. I wonder if it could be some type of California emissions part, but I am located in Georgia and the only owner of the vehicle.

As info, we bypassed this valve and the CEL light did not come back on again. It's been about a month with no problem. I had the emissions test done and everything checked out good. I still don't know what this part is.

Go back on myisuzuparts and do a keyword search for ORIFICE; RECIRCULATION (part 591 on the drawing) sounds to me like that is what you are describing but not sure. Or maybe CONNECTOR; VENTILATION (part 584).

It looks like it is the "orifice; recirculation". You are very, very good. We could not find anyone who could tell what it was or what it did or how to order it. Since everything works and it passes emissions, I am just going to leave it as is. But I'll know what to buy if other problems develop. Thanks so very much.

Did he say, "orifice?"