Well, I never heard of a cummins with piston slap before. The old 225 mopar
slant 6's were famos for piston slap that sounded just like a rod nock or wrist pin.

If you were able to turn each injector off as you proceeded and the noise was still there, I guess its not a fuel knock.

I'd do a search on the site for knock or something and see if anyone else has encountered what your hearing.

Dave

 

I believe I would find another garage. Unless someone has stuck a CRD in that 2000, You cant turn the cylinders off one at a time. ISX yes, 6BT with VP, NO.
I doubt if you have wrist pin issues. If anything I would be looking for low injection pressures giving a poor fuel spray or a bad injector. All diesels rattle worse when they are cold due to late combustion because of low cylinder temps. That the reason they rattle worse in cold weather. If you have a real good ear, you can listen to one and tell if you have a bad spray pattern, find an old timer. If you have a bad spray pattern you will also have some excessive smoke , low power, harder starts. One bad injector will cause a slight miss, because of one cylinder being down. Drive it. If the fuel economy is good, the power is OK, just use it.

 

Just out of curiosity, do you offten operate this unit at 2800? I run mine between 1200 and 2200, might see 2500 if Im in a real hurry.

 

These things can handle 2700 rpm at full load all day infinitely.

I wouldn't think twice of running up a hill with a heavy load at 2800..

 

If it goes away when it's warm....are you sure it's not your VP..just making noise to tick you off.

 

Well I am thinking of driving her till she runs forever or blows. All the injectors are brand new EDGE 75 horse. Is there a way to test a vp or is it one that works or flat out doesn't.

If this matters at all the tach, sitting at idle will jump every now and then about 100 rpms????


Also I dont run it at 2800 rpm, this was just testing.


Thanks for all the help with the brain stormin guys!!!

 

24 valve ISB's with VP44's can turn cylinder off with the use of a snapon scanner. Trust me it can be done, how do you think 3 cylinder high idle works? I've done it many times trying to find the noise in my engine, can't find it so I run it.


Thats the conclusion I came to, run it till it blows and that was 40,000 miles ago and my noise never got worse.

 

Dang Cole, You have dug deep into this....... Let me know if your not satisfied with your injectors and want to go back to stock. If she likes the rest of the truck I say run it into the ground. I'm likin mine so far, thanks for all your help gettin me up to speed on these rattlers.

 

[QUOTE=COLEMAN1001;1980801]Well I am thinking of driving her till she runs forever or blows. All the injectors are brand new EDGE 75 horse. Is there a way to test a vp or is it one that works or flat out doesn't.

I think I read on this website a month or so ago that the dealer can make the vp44 run independent of the engine with specific equipment. Love to see that work. Wish I remembered title of the thread.

 

The equipment is a idle only tool.
Have tried reading post and may have gotten off base.
Dealer has said two wrist pins bad. Someone else mentions # 6 cyl but no mention of blowby or white smoke. Hummmm! In a effort the learn, may I suugest a test. Add a quart of TW3 two cycle oil to tank before fill up. This will give a 1-128 approx ratio mix that is suggested as a lubricity addive. My take is the oil changes the cetane rating of fuel enough to reduce detonation and quieten engine. others have extrapolated similar noise reduction. If this does quieten, then no real engine problem and get on with your life.
AS some have mentioned,run it till it breakes. Excessive time has been spendt trying to diagnois reasonablly normal engine noises to no avail. Can you hear it from drivers seat with windows up and radion on??

 

That is correct. The Dealers drb3 scan tool also has the abilities to knock out one cylinder at a time. I suspect that is what the dealer did to the OP in this thread. The most likely did it cold and heard a noticible change in the noise.

 

interesting, I did not know you could do a cut out test on a mechanical injection pump. I know the 24v is electronic controled but i thought it had the same rack system like a 12v did? so you couldnt shut off one at a time? Can someone explain how that works? I imagin all the goodies are in the vp44?

 

you can not repeat can not electronically kill one cylinder at a time on a vp44 with a snap on, drbIII or any other scanner. the only thing controlled electronically on a vp44 is timing and fuel quantity. on a cr cummins yes on a vp44 absolutely not. you can isolate cylinders by cracking fuel lines just like any other mechanical pump. The vp44 is a mechanical rotary pump with solenoid controlled timing and fuel quantity controls with mechanical spring poppet injectors you can not individually control cylinders electronically.

 

Ok, so apparently having done several cylinder cutout tests on my own 01, as well as many customer trucks, the cylinders being dropped is obviously not what happened.

So, can you patiently and clearly explain to me, why the scanners not only have the ability to turn individual cylinders off, but appear to actually do exactly that. Thanks in advance.

 

I believe the answers lies in the bold text. Shut the fuel off to one cylinder in the pump and you effectively shut that cylinder down.