Wildwhilly04

The truck just started this yesterday and I had to baby it home only going 30mph 🙄 it has a rough idle and when I give it fuel it cuts out and spits n sputters at 2000 rpms, itll recover after i let off the fuel and it goes back to a rough idle.. the fuel rail pressure is what is bealived to be the problem at idle it's at 24k and when i press the accelerator it begins to drop down to 1k give or take.. the truck doesnt shut off just stumbles and no power.. I replaced the injectors,tubes, new lift pump, new FCA, the prv is blocked off, I did a cp3 flow test and it passed, and no codes are being thrown.. I'm going to replace the cov today when It gets here thinking that might be the issues but i honestly have no idea where to go from here

Don M

The truck idles at 24k? Check the wiring to the MPROP (fca) and be sure it has not lost connection.

Have you done any other work to the CP3 recently?

A blocked rail can eventually lead to cracked/failed injectors on a street driven truck. Just an FYI. The body of the injector near the hold down clamp is too thin for constant pressure pulsations that can occur with a blocked rail. Basically, it is akin to a coat hanger being bent back and forth until it becomes two pieces. (-:

Green_Machine

I'm a bit confused on your post. You said it just started this recently, but you have changed injectors etc....

Did you change injectors before the issue arose, or after?

If you really have 24kpsi rail pressure at idle then you definitely have an issue. It points very much to FCA I would think. I can think of many issues that would cause low pressure, but only one that causes high pressure, the FCA. You have changed it, but as noted above, check the wiring, and if you have the means, check the signal to it with a scope. If I remember right Geno's has a replacement connector assembly for the fca-if there is any doubt about it's quality, I'd change it.

I would check/change the fuel rail pressure sensor though, to make sure you are getting good information. Not sure what you are using for a guage, but you can use a voltmeter direct to the sensor-should be .5V at 0psi and near 5V at 26kpsi....Expect around 2V at idle.

The rough running is a concern. If the rail pressure is high (Pull the FCA connector), it sounds like a 12 valve, but should not run 'rough'. I wonder if you have a leaking connector tube? Did you do the work yourself, and if so, what did you torque the connector tubes to? Otherwise it sure sounds like an injector problem to me. Any smoke on the misfire?


Chay