What are symtoms of a bad FCA?

[ZBrooks]

When my FCA went out, it would start and idle just fine, but would fall on its face around the 2k rpm mark while accelerating.

 

[hirschjn]

Where is the "Constant Pressure Relief Valve" located, is it the one on top of the rail??

 

[TCDiesel]

Yes. . the factory has Dump Valve... At this point we Are the only company rebuilding and upgrading the factory Valve. the valve is located nexts to the Pressure Sensor.

 

[JJPage]

How hard is the Constant Pressure Release Valve to install? And where?

Where is the "Constant Pressure Relief Valve" located, is it the one on top of the rail??

You also have a COV(cascade overflow valve) on top of your CP3 injection pump. It is the component that looks like it has a large BB in it's center. If it fails,gets stuck partially open, your fuel will bypass to the return line. It can also weaken, just like the rail pressure relief valve, when that happens to either valve your truck will behave as if the fuel filter is constricted.

 

[jakprince]

So are you torqing the screws when you replace the fca or do you just tighten them up. I think mine may be bad but im kinda scared to mess with it from fear of stripping them out.

 

[zzman]

I just tighten the screws. All seems good now.

 

[steved]

The main thing with the FCA screws is make sure your get the correct Torx driver... the screw itself is fairly stout, but the head strips easily if you use the wrong Torx bit.

 

[jakprince]

OK so what size is it?

 

[Trino]

Ron,



A failing FCA in a pure stock engine will sometimes idle a little rough but that symptom can be erratic or random. In other words, it may occur or may not. The engine may also produce a mild rattle at slower highway speed with varying throttle input a little like the detonation or spark knock that can occur with a high compression non-computerized gas motor using low octane gasoline.



In a modified engine, diagnosis is far too complex and uncertain for me to suggest what your problem is.

Would a check engine code appear if this part is bad? Anyone know? I have similar problem. Rough on idle and ifi give it a little fuel the idle gets rougher where feels like a gas engine mis fire. But will get smooth at a higher rpm... . 06' 4x4 megacab.

 

[HBarlow]

In my experience no, it won't. It is a common failure item on the later model HPCR engines and will only cost you about $150 if you make a mistake.

The rough idle that gets worse with a slight increase in rpm does not sound to me like an FCA symptom.