FCA issue.

Happened to the wife while she was driving. She got home and now my idle reads 200RPM's, coincidence? Maybe I didn't notice the 06 tach issue had popped up previously?

Anyways, I cannot for the life of me break the T-25 mount screws loose to remove it and shake it for rattle. The truck seems to run fine at this time, so I'm sure it is sticking occasionally. Will any fuel treatments help alleviate the stickiness? Or do I just need to order one from Geno?

Any tips on removing screws? I tried tapping them on the driver with the T-25 in place and just tapping the screws themselves.

P.S. I also noticed an oil smell when she pulled up, but no leaks and I'm not making oil, no diesel odor to fuel.

 

I had a heck of a time getting mine off too... I took a long flat bar, just a piece of metal stock, and tapped on them from the top and the sides. I took the front tire and wheel well out, that helped a lot to.

If you're having an oil smell and high rpms, I'd look at the turbo, too. Check your intake to make sure you're not blowing oil from the turbo...

 

True RPM's are fine. I'll try knocking the screws around with your advice.

Since I'm in Cali I can sue you if it goes awry.

;^p

 

Ah, got it.

Go ahead, brother... all you're going to get is a beat up hot rod and some bills!

Maybe I should specify... don't try to break them with the hammer... tap gently. I was told the stainless screws bond with the aluminum alloy (or whatever it is) of the CP3 and make it hard to remove. Once I tapped mine, they came right out.

If you have a small impact driver, that would probably work too.

 

I put a 1/4" drive ratchet wrench on a T-25 and eased on it till it popped loose. Are you using just a screwdriver type tool or a ratchet tool?

Also, THE SHAKE TEST FOR THE FCA IS NOT AN OFFICIAL WAY TO TEST. I just went through this in a recent thread (P0148 issue). I suspected the FCA at one point of my diagnosis and so I purchased one. The brand new one didn't rattle and neither did the one that came out of my truck. What you want to do to check it is when you turn the key off, wait a second or two and listen for a click. That is the FCA shutting off. I put my hand on it so I knew the click was coming from the FCA and not from something else. Also you can put a meter on the 2 probes in the back of the FCA and see what the solenoid resistance is. The range was supposed to be 1.5 to 5 ohms. Mine as well as the new replacement both read in around 3.3 ohms.

I'll see if I can find that page in the manual again. Edit, it's in section 9, page 1277 (P0251-CP3 pump regulator control diagnosis). There is a 10 step process to completely diagnose this code.

I'm not saying that's not your issue since the P0251 specifically points to the FCA but it would be nice to know for sure before you buy a $100 part you may not need.

 

Thanks Scoutman, I was using a nut-driver styled Torx. I'm really strong, I swear...even my mom says so.

I'll pick up a socket style.

It ohm's fine, but it is intermittent (Sticking) so I'm pretty sure it's the FCA, if not I could always mod one of them for future use or just keep as a spare.

I ordered from Geno's, I also noticed my track bar bushings are completely shot so I ordered some of Luke's that Geno sells. Just need to find some Heim adjustable end links that will support up to 6" of lift because mine are more crooked than Congress.

 

Well that was easier than changing the fuel filter.

Stood on bumper opening, reached down with a 1/4 drive ratchet and T-25, screws popped loose with ease. Even the lower screw was easily accessed from top-side, just used my other hand to feel its location to guide the torx.

Anyways, much better, smoother idle than I've had in a long time.

Also, oddly, my auto is shifting more decisively. I used to get a rubber band feeling like shift, now she just shifts. Don't know why that would change?

I know the code has to be cleared, but does the CEL turn itself off after so many miles or starts? I've only driven her twice since repair and they were short trips.

 

Some codes clear by them selves, some don't. Some codes won't clear with a reader but will eventually clear themselves if the problem is gone.

 

Thx verdes

 

Got P0251 again today. I was on it hard passing a vehicle on a decent grade (101 south 40 miles north of Paso Robles). I hit 90mph, she hiccuped, dinged, CEL came on. I was about 150 miles into a 600 mile drive. I pulled into the next gas station I could (35 miles), didn't want her to not restart in the boonies. Anyways, harness was tight and she ran fine afterwards under all throttle requests. After 2 restarts in the next 150 miles the CEL went out. I'm at 120K so maybe my pump is starting to fail?

 

Probably injectors, you could test the total return rate to make sure.

 

P0251 - CP3 Pump Regulator Control; Injector Pump Fuel Valve Feedback: The ECM detects a discrepancy between PWM supplied to FCA and PWM returned from FCA.

Possible causes: - Intermittent condition

- Fuel Control Actuator - Return wire open from FCA to ECM

Supply wire open from FCA to ECM

Supply circuit shorted to voltage - ECM

Make sure the ECM harness is not damaged and clean the plug connections up as well. Also check the 15/16 nuts on your injector tubes, sometimes they work themselves loose and will throw that code.

 

From the factory service manual :

P0251- CP3 pump regulator control step 1: Ignition on, engine not running disconnect he fuel control actuator (FCA) harness connector connect a incandesant test light across the the driver circuit and fuel control actuator circuit harness connector. the ECM will perform a selftest of the circuit whih should mometarily flash the test light brightly, one time, aprox 20 seconds after being connected Did the light flash brightly? yes- replace pump no- go to step 2

step 2: Turn ignition on disconnect ECm harness connectors measure resistance from the FCA driver circuit between the electronic fuel control acuator harness and the ECM harness connector Is the resistance less than 10 ohms? Yes- go to step 3 no- repair the (K181) fuel control acuator driver circuit OPEN .

Step3: measure the resistance of the K31 return circuit between the FCA harness connector and the ECM connector. Is the resistance less than 10 ohms? yes- go to step 4 no- repair/replace the engine wiring harness .

step 4: measure voltage between the K181 FCA driver circuit connector and battery ground. Is the voltage more than 1 volt? yes- repair k181 FCA driver circuit shorted to to external voltage no- go to 5 .

step 5: measure voltage between the k31 FCA return circuit in the FCA harness connector and Battery negative. Is the voltage great than 1 volt? yes- repair K31 FCA return circuit shortage to external voltage no- go to 6 .

step 6: measure resistance between reurn circuit in the FCA harness connector and Battery negative. Is the the resistance greater than 10 ohms? yes- repair K31 FCA return circuit shorted to K181 FCA driver circuit no- go to 7 .

step 7: measure the resistance between K181 FCA driver circuit and battery negative. Is the resistance less than 10 ohms? Yes- repair K181 shorted to ground no- go to 8 .

step 8: mea the resistance between the k181 FCA driver circuit in the ECM harness connector and all other circuits on the ECM connector. is the the resistance less than 10 ohms? yes- go to 9 no- repair K181 shorted to another circuit .

step 9: measure resisance between the K31 FCA return in the ECm harness adn all other circuits in the ECM connector. is the resistance less than 10 ohms? yes- go to 10 no- repair K31 FCA return shorted to another circuit .

step 10: reconnect ECM harness connectors Ignition on, Engine not running. Disconnect the Electronic Fuel Control Actuator Connnector. Connect adn incandesent test light across the FCA driver pin and the FCA return wire at the fuel control actuator connector the ecm will perform a self test which should flash the test light brightly, one time, approx 20 seconds after being connected
NOTE: compare the brightness to that of the direct connection to the battery. Did it flash brightly? yes- refer to INTERMITTENT CONDITIONS symptoms (diagnostic procedure) no- Replace ECM

 

Thanks, Doc.

I'll perform those tests this coming Saturday. Too dark by the time I get home after work.