03 cummins Truck started knocking a few thousand ago, had injectors checked and replaced all of them, quieted it down a ton, but not completely. when just at cruise speed you can here it, but once I get on the throttle it goes away. It does the same knocking when it's cold, and I get on it pulling into traffic, until the truck seems to get fuel and take off. I turned up the pressure on the f100 and it didn't seem to make a difference. It does it really bad when I have the Ramifier plugged in and the truck isn't up to temp and I get on it even 1/4 throttle. It's like it's trying to get fuel, but it isn't getting it. Once the truck is up to temp, it still knocks a little, but it has no problem scooting down the road even with the ramifier on and taking off from a dead stop. I have tried re-programming the smarty to diff. levels, doesn't really make a difference. I never noticed the knocking before the injectors went out. After reading a thread below about a possible tired CP3, it made me wonder if that could be a culprit, or if it's just my mind worrying me, because once the truck is warmed up it has no problems. I asked in another thread if possibly I'm trying to ask to much of my cp3 with my mods, and was re assured it should handle them, so I crossed that off of possibilities as long as the pump is healthy.

 

Do you know what your rail pressure is? Could be the FCA on the backside of the pump acting up.

 

I had read that possibility on the thread you have going on, just wasn't sure if that could affect it.... But, I don't have my pressure gauge installed yet. Shame on me I know. Is there a way to bypass the FCA?

 

No, the ECM needs to read the FCA in order to prompt pressure ramp up to the rail.

 

I haven't posted in a long while but if you haven't put and aux. fuel water separator on your truck you ought to. Because any kinda trash/water gets pass your stock filter in has a tendency to screw with the FCA Valve. It will make codes come up saying High/Low Pressure on the fuel rail. It will corrode the fuel gauge sending unit. I know from running some cruddy fuel in mine. Mine is all fixed now with a few upgrades to it for fuel delivery purpose. Just my 2 cents

 

Are your valves all adjusted properly?


47

 

47dodge, I had just thought of that this morning and was logging on here to ask that same question. I bought a new 85% cp3 pump and getting installed Monday, I figure I will have them check it while it's In there. I thought I told them to check that when I had the injectors replaced, but sometimes selective hearing comes in to play I have found.

 

Or they did check them and one of them could have come loose. I know when I redid the head on my JD diesel tractor adjusting the valves made all the difference in the way it ran and sounded.


I have seen tork convertors come lose or crack/break from the flex plate on gas engines and create a knock that can come and go depending on load and temperature. Don't know how the diesels are setup as I haven't been into one there. Just a thought. On the old gas stuff you could pop the inspection plate and check/tighten the bolts.

47