2003 engine rattle - knock on deceleration

[posey-smoker]

I need some help. I have a strange engine rattle on deceleration only. It sounds like a rocker arm is loose. The rattle is random. It can be heard when slowing down with the windows down. The sound is not the same each time.



I checked the valve clearances yesterday and all are in tollerance. Nothing loose. Thought a lifter might be loosing pressure.



Any Thoughts???

 

[posey-smoker]

OK I got no help so here are the additional symptoms I see.



The symptoms exagerate when I turn my Quadzilla box up from 0 to 60 to 100 to 160 HP. It gets louder when i turn up the power. When I turn it down to 0 HP increase you can barely hear it. Sometimes I get a vibrating idle like there is an injector is dirty or bad.



I keep using Valvoline diesel injector cleaner to see if it helps but it does not.



Thoughts????

 

[p-Bar]

Injector??

 

[mberry]

I agree. It's an injector. Or it could be the FCA. I would start with the FCA since it's is the least expensive and cures a lot of what some people think are injector problems that aren't.

 

[MSkyrman]

I agree. It's an injector. Or it could be the FCA. I would start with the FCA since it's is the least expensive and cures a lot of what some people think are injector problems that aren't.

Sorry, what does FCA stand for?

 

[rbattelle]

FCA is the fuel control actuator. It's a module mounted on the back side of the injector pump - the only electronic module mounted on the injector pump, so it's easy to identify. It functions to determine how much fuel to send to the high pressure pumping chambers, the remainder being sent to the overflow valve, which returns some to the tank and uses some to lubricate the pump.

Ryan

 

[JJPage]

Cummins part #4932457, Bosch #0928400666, Dodge #5183245AA.



Cummins will be around $100. 00, Dodge will be twice that.



My TST was causing a similar rattle in my truck, sounded normal while excellerating or cruising, but let off after excellerating, and it would rattle like crazy. I sent my TST in for upgrading, and no problem since, it may just be your Quad box, you said the rattle is almost non-existent with it off.



Just my . 02

 

[JHedman]

My 2005 had the rattle you described when the rail pressure relief valve was bad.

 

[JJPage]

My 2005 had the rattle you described when the rail pressure relief valve was bad.

You know, that makes sense, kinda... excellerate, let off, pressure spikes especially with a fuel box, injectors are closing down, forces the fuel through the relief valve, and they(relief valve) do a cyclic pop, when they release because of the pulses.



I capped my rail around the same time I sent my TST in for the upgrade, I just assumed it was the TST.

 

[posey-smoker]

OK it's been a while since I posted on this topic. But here is the latest. When I turn my Quad box up from 60 HP to 100 HP to 160 HP the rattle getts louder with each HP change. You only hear the rattle when slowing down. As a matter of fact as you hear it rattling you can cycle the HP selector knob up and down and the sound gets louder and quieer depending on the way you turn the knob.



It is definatly fuel pressure related as the Quad box changes the fuel pressure on each setting. The question is what part is going bad?

 

[p-Bar]

OK it's been a while since I posted on this topic. But here is the latest. When I turn my Quad box up from 60 HP to 100 HP to 160 HP the rattle getts louder with each HP change. You only hear the rattle when slowing down. As a matter of fact as you hear it rattling you can cycle the HP selector knob up and down and the sound gets louder and quieer depending on the way you turn the knob.



It is definatly fuel pressure related as the Quad box changes the fuel pressure on each setting. The question is what part is going bad?

Would be interesting be monitoring the high pressure side of the fuel system while this is happening. You do trash the relief valves with the pressure boxes

 

[posey-smoker]

I dont have a pressure guage to monitor the fuel pressure change. I thought about purchasing one but I dont want to spend $190 for one yet. I bet my releif valve is trashed. Would it be advisable to spend $50 on a releif valve block to test/eliiminate the issue? Thats the question at hand! This has been going on for some time now.



Thoughts anyone?

 

[p-Bar]

I would cap it off but when you can afford it put on a high pressure gauge.

 

[JJPage]

You might also try re-phasing your CP-3, seems to have cured a few excessive rattlers.

 

[p-Bar]

You might also try re-phasing your CP-3, seems to have cured a few excessive rattlers.

1st to hear of "re-phasing" what is entailed to doing this?

 

[cerberusiam]

You might also try re-phasing your CP-3, seems to have cured a few excessive rattlers.

Thats what I was thinking but have never heard it be an issue on decel.



Phasing the CP3 entails loosening the CP3 drive gear and rotating the engine 20 degrees at a time then tighten bolt and check again. It phase the compression of the CP3 high pressure cylinders to the compression stroke of the engine and minimizes any gear lash noise.



Capping the rail is easy to do, just pull the banjo out of the top of the relief valve and tap the inside for a 1/8 pipe plug. Easy to remove when your done.