98tdi wrote:
Fuel rail solenoid. If you examine the pins closely with a good light, you won't even need to look them up. I can't remember the pin #'s, but they'll be crispy if that's the problem. Yeah, no code often[/quote]
I will check that out never thought of that
Still if the pins were for some reason not making contact, and I had no fuel coming out of pressure side of cp3
(An unplugged connector at the FQS back side of the CP3(?) or any lost signal will result of MAX fuel passing through the CP3) I don’t think the solenoid wiring would cause that
Since I bypassed the electrical side of the equation by unplugging the fca
(FQS?) it wild
(would?) default into max rail pressure (which it did not)
If you are trying to describe the condition indicated by my corrections, then this isn't technically correct. It would default into max fuel quantity. Pressure depends on other things downstream.My thoughts are the cp3 has failed or has issue with either the fca or cascade overflow valve[/quote]
Ok I'm trying to interpret your statements here, but you're using a foreign term (FCA which means Fiat Chrysler Automobiles), so I will do my best.
"Still if the pins were for some reason not making contact, and I had no fuel coming out of pressure side of cp3 I don’t think the solenoid wiring would cause that"
The HighPressure side of CP3 is easily tested for volume by disconnecting any of the HP fuel line joints.
You don't specify to which solenoid wiring you are referring, but the only possible relevant one would be FQS (fuel quantity solenoid) attached to the CP3. This solenoid's natural state is "full open" (maximum fuel output). If there is no fuel output from the CP3, then either this valve is stuck closed, or the low pressure transfer pump inside the CP3 has failed in some way. If the ECM is giving a signal telling the FQS to shut fuel electronically, the only reason that would happen is the Fuel Pressure Sensor is giving the ECM incorrect information.
If there is NO FUEL output from the CP3 when cranking (except for return) The only way it could escape is via COV (Cascade Overflow Valve). This is a mechanical device, not electronically controlled in any way. And I'm not sure if it's even capable of bypassing full volume, especially in stage 1 or 2. It's primary function is to make sure the first place fuel goes it to the lubrication passages (0-44 psi). Secondary function is to bleed off air from supply fuel (45-77psi) Above 77psi goes to the HP pumping plungers and out to the rail.
So for any fuel to bleed back through the return, the pump has to be working somewhat.