So, after many attempts to solve the problem myself I'm gonna post and see what you guys who've had a CP3 failure have to say.

The truck is modded a bit but running brand new stock bosch injectors, new 30,000 psi pressure safety valve and a new FCA. Mileage is at 150,000 km. All electrical connections have been checked and rechecked as a means to an end....

The problem I'm having is that under load it missfires severely. I have a rail pressure gauge and a lift pump gauge. Under load the lift pump puts out close to 13 pounds and the injection pump in the neighborhood of 22000-25000 psi. But realistically its hard to peg the RP as the gauge crashes during the misfire . I sense that I'm getting enough fuel with these pressures but question it since I'm having issues with this misfire. It's so bad the whole driveline just shudders and the truck just falls on it's face. Now, this is only once I crank the chip up higher trying to add power. Approximately anything over level 3 on hp and 3 on tq. Its seems more prevalant at lower rpm than at higher or mainly when I'm looking for a higher torque setting.

Would a timing issue cause this? Any ideas besides the CP3?

 

Have you checked for any codes? I would think something that severe would leave a trace of some sort in the ECM.

 

Codes would help zero it in.

Possibly draining the rail in kill mode? I did the Wicked CP3 mod kit and it cleared up a similar problem on mine.

Possibly popping the PRV and weakened it so it is letting go sooner? Can you borrow a spare to test a different PRV?

 

He claims to have a new PRV but unless he's popped that one too I don't see it as being the problem. I think if the PRV let go he would just see a severe loss of power and not so much the popping.....kinda like letting off the throttle. I think he something else going on here.

 

That is a fair assessment. I mentioned it because that was one of the steps I took in trying to figure out my rail drain problem and it isnt too expensive to check out. Ultimately, that also led me to bad injectors once the rail pressure held but the OP indicated those are new as well.

 

I checked for codes. Nothing.... My next step is to try a CP3 mod or a new pump altogether. I'll look into the wicked one you spoke of. How does one check and adjust timing? Its all to do with the computer right?

 

See if anyone up your way might be willing to borrow you a smarty for a few rips to play with different timing settings.

I wonder if your cam is coming into play as well, but youve had that in for awhile though havnt you?

 

Yes, I'm starting to wonder if its the cam as well. I'm going to call the guy who performed most of my work putting the engine back together. He pointed me in the direction of the FCA and PRV. I'm sure this is a fairly simple fix, its the diagnosis thats the elusive part!

 

Yesterday I decided to take some advice and try a smarty. We unhooked my TST entirely and uploaded the smarty program on revo5. From the instant I gave it throttle it was a different truck. I waited for the misfire to happen but nothing. so we hit the highway and I thought for sure it would starve for fuel and misfire.....I floored it, nothing but tire smoke and wicked acceleration. The twins kept the coal smoke to a minimum and it just hauled butt. So, for fun we uploaded the revo 7 program. WOW!!! No fuel issues just go like heck. I always heard the smarty's were good but that put the fun back in hotrodding for me.

I'm having trouble believing that the chip could cause me so much grief but it is what it is. At least it wasn't anything mechanical as I've got so much cash into the truck.. I'll send the tst back for a reflash but I'm tempted to just screw it and buy a smarty.