Symptoms od bad 3/2 directional control valve

[ccrisson]

Can the 3/2 directional control valve ( also called "running losses solenoid" or fuel control valve ) cause fuel pressure at the fuel rail to drop rapidly after the engine is shut off?
When I bypass this device the pressure at the rail holds. When it is connected the fuel pressure drops rapidly once the engine is shutoff. Also the pressure will drop when the key is turned to the run position but engine is off. The pressure rises to about 43 then drops rapidly.
I attached a fuel pressure gauge to the return line side output port of this device and plugged the return line after the valve. The pressure holds fairly well.
So I conclude that the fuel pressure is dropping because this device is allowing the fuel to bleed back to the tank. I know this is part of the purpose of this device, but if the system will not hold pressure when the key is first turned on what holds the pressure? I replaced the fuel pump, the fuel regulator, and the fuel filter. I then tested the check valve in the fuel pump. No problem found, it holds pressure.

[Dmitry at Pelican Parts]

What year and model is this in reference to?


-Dmitry

[ccrisson]

1999 M Roadster s52

[fiatbrett]

Hi ccrisson, I'm having a hard starting problem with my 2000 M Coupe w/S52 engine. I see the same thing with pressure dropping from 45 to 29 PSI within 15 min. at the fuel rail. I've replaced the fuel pump, FPR, and fuel filter without success. The car takes 4-5 seconds to fire when starting after it has been sitting for a couple of hours. After it does fire, the car runs normally. I'm wondering if it could be the electro valve in the 3/2 valve?

Do you experience hard starts, too?