fuel pressure regulator solenoid

[deez]

Today I was digging around under the hood, mostly cause I was bored, and looked at the fuel regulator solenoid and wondered just what it does? Mine isn't hooked up, as one of the first things I read when I got the car years ago was to unhook it. But can anyone, just out of curiosity, tell me just what it does?
Thanks

 

[FlyingEagle]

Hot start made easier.

 

[The_Big_Weave]

wouldnt it be easier cold start?

 

[TurboTrader]

Nope, it is for Hot-start purposes. It bumps up the fuel pressure to help start the engine back up when it is warm. It has something to do with gas vapors that build up in the lines, fuel rail, etc., that can in theory make a hot-start difficult. By bumping up the fuel pressure temporarily, the fresh flood of gas through the lines washes the vapors through. It was a good theory on Mitsubishi's part, but not entirely necessary.

It can easily and safely be eliminated. I have eliminated mine on all DSM's and my GVR4 with no ill effects really, other than the occasional sputter/misfire for several seconds only if I let the car sit for exactly 20-minutes or so on a warm day and go back and start it. I can only attribute it to eliminating the FPS, but no big deal, and so very occasional, I could care less.

 

[deez]

very interesting. so when I experience something like vapor lock on a carburated car after its been sitting a bit, that would be the solution.
And upon looking at mine, the nipple is broken off. Does anyone out there have a spare?

 

Yes, its the equivalent of vapor lock on a carb car. Just think how hot that fuel must get sitting in that rail while you are in the convenience store. It actually starts percolating, and raising the fuel pressure 7-9 psi helps somewhat to keep it liquid I guess.