JD 6068 in Magnum 235 - turbo replaced, ran good, then rough, now will not start.

[03hdrk]

Symptoms when brought in: runs rough, black smoke, knocking (sounded like injector not bearings), code - turbo actuator not functioning or out of calibration (don't quote me on the wording of the code.

Work done:
Checked turbo impeller - loose but spin. Actuator would not move. Removed turbo - aluminum pcs fell out of exh side while on the bench - then actuator started moving a little. Replaced turbo assy with factory unit (ouch $2400 at only 6000 plus hours).

Started unit - ran normal for a about 10 seconds, but has a little black smoke. Then started running a little rough and smoke increased. Killed the engine and took a look around - no codes in the Magnum controller.
Restarted - hard to start, lots of black smoke. After reaching RPMs knocking started and more smoke. Killed unit

Now it will not start - no codes visible.

Check to make sure turbo impeller moved freely - it is OK.

Opened oil filter - no metal visible.

Why would it run normal at first? Then go bad

 

[partsandservice]

More questions ... Is it a 12 or 24 valve. Sounds like it dropped a valve. Have you removed rocker cover?

 

[lantraxco]

Better question: What came out of the engine and jammed up the actuator in the variable turbo? Hmm? Just a guess.

 

[partsandservice]

No fault codes exists for pieces of valve in turbo.

 

[lantraxco]

LOL, nor a hole in the side of the block.... oil pressure was fine as the bearing smeared the drilled hole closed, did of course cause a misfire but not enough to trip a code. I'm sure if it hadn't shaken the operator's teeth loose bad enough so he shut it down, it would have sooner or later.