Is your rail sensor in the back of the second pump or on the rail, voltage should be in the 4.0s at idle on the fca.How much return fuel out of the head do you have?

 

Sounds like you have a bad FCA too me....

BTW, If you are free revving your engine, pressure will not be high....pressure is added when load is added.

 

Nice Video Bean.....great Pull!!

 

RPS is in the rail. Voltage stays around the 2.0's most of the time. Will only jump up to the high 3's when I try to rev it up while its acting up.

 

I would try to run it of just the stock pump and see how it ran.The voltage should be about 4.8v at idle and should go down as you rev it up but if it is not under a load ot will not go much below 4.5v.If it is at 2.0v at idle it seems like the ECM is comanding the FCA to open up for loss of pressure somewhere.I had a promblem on one truck like this but the rail sensor was in the back of the pump and it was messing with the readings somehow going to the ECM it ended up being that pump was bad.Are the FCA voltage readings coming of a scanner or are you checking them at the FCA with a volt meter.

 

Reading from a scanner.

Plan of attack for today is change bottom FCA and if that does nothing like I feel it will I will start swappin pumps. I will check the voltage at the FCA and see if it agrees with the scanner.

 

More wierdness, Scanner shows anywhere from 2.0 - 3.9 like we discussed, factory harness on bottom pump shows 0 voltage on top wire and 4.9 on the bottom wire at idle, but its jumps around like everynow and then will jump to 14v and its also varying on my tester from - to + the whole time. Now if I try to rev it up the voltage goes to full voltage 14v+. I dont have any other 3rd egns around at the moment to check it against but sound like there is somthing messed up there. If it is goin to 14v it should be dumping all the pressure but the scanner shows 18k+.

Changed bottom pump also no change. Next is top pump.

 

Top pump changed and no difference. Losin my freakin mind. Pretty much the only thing now that I have not chaged out is injectors and that is where it all started, to me it acts like its an electrical/ecu thing but I have changed everybit of that out.

 

Did you trying putting the fuel system back to stock.I would put it back to the stock single pump with a brand new FCA not modified.At least that would rule out the FCA ,second pump and controller.If that dont work it would be easier to narrow down.4.9 to 4.8v is right on the voltage at idle ,if the ground breaks on the meter it will read batt voltage probally why you were seeing 14v its hard to get good contact in the fca plug if you have big ends on the probes on your meter.Either way if it was getting over 5v it would shut the truck down.If you unplug one of the fca while it is running does the pressure max out?

 

Neither FCA is modded and I have tried other ones so thats not it. It now has two stock pumps and two stock fcas.

Meter has a real sharp probe so I was just probing the wires themselves, was'nt sure if that was normal cause I didnt have anything to check it by.

If I unplug the FCA it does go to full pressure.

 

Been following this Bean. One thing I know is that you should never see anything over 5 volts on the rail sensor. There is either a wiring issue or something causing the voltage to raise. What else is involved with the rail pressure sensor? What else do you have plugged into it? Look in that direction.

 

That is radical.

 

Ok back at this again. Sent all of my injs and rail and lines to Don and everything checked out fine. Sent pumps off to get checked out, one was a little water damaged but nothing to cause the problems I have.

Put it all back together and start it up and its really smooth now, even smoother then before and seems like less smoke at idle so I think maby I have it. Nope, still acts up. Heres what I have found while watching the scanner and observation..

Start it up and take it to 2000rpms. Rail pressure is about 9000, hold the rpms and in a few seconds I can tell its starting to struggle to hold the rpms and it starts running rougher like it dropped a cylinder. As it does this rail pressure starts to climb higher and higher the worse it runs. I am assuming it is dropping cylinders, duty cycle stays the same so as there is less fuel used rail pressure climbs.

Now the other screwy thing is the fca voltage. I tested another truck and at idle it pulses voltage and stays right at 4.9-5.0v. On my truck it shows around 4.9-5.0v but pulses from - to + very rapidly and every few seconds spikes to 13+volts.

It idles very smooth and when I get that first rev in its super smooth but then after that it goes down hill. Still no codes.

 

How is this wired up? I mean , like there are two FCA's, right ? Is there another controller for the second FCA? I am thinking there is something going on with that. Where could it get voltage from? There almost has to be a wire rubbing or a module giving it that voltage.

 

I'm with vzdude. What controller are you using on your 2nd cp3.