Is it hard to pull the valve cover and check valves opening and closing, springs, rockers?

Good to see how GDE is in on this thread, thanks guys.

How far are you from Waco,TX. ?

I just read this thread.

In your first post it sounds like it's running on one cyl
With the injectors out it sounds normal.
You had the injectors tested and they tested ok

If all of this is true AND you get fuel to the rail (you do because it runs on one cyl)
AND you have done a cyl cutout test and cyl 2 3 4 do not make any difference in the sound or rpm of the engien aka it runs on cyl #1 only
Cyl 2,3,4 did not make a difference in sound,but each time I pulled 2,3,or4,the rpm's increased ever so slightly

Your point of failure is, one, the wire harness, and two, the ecm.

Since (i have not checked this is memory) injector 1 runs on a different harness than 2 3 and 4. I would start there.
One of the most likely parts of an ecm to fail are it's injector actuator circuits. That said, ecm failures account for 1% of electrical problems in modern heavy and light duty electronics, so be sure. Pin out all of the injector connectors and follow them to the ecm connector, measure for excessive resistance. measure them for resistance to ground, and resistance to 12v (with ecm disconnected) normally the ecm would reveal these faults, but this is always the first step in any troubleshooting manual i've every read for any engine, Cat Cummins Detroit etc.

If the shop is to be trusted we can only assume that in the injectors tested, solenoids actuated properly.

1. not injectors.
2. Not fuel delivery
3. not mechanical
4. is electrical

Also i read someone advised the use of ether. DO NOT USE ETHER on anything with glow plugs (this mean all crds) or a intake grid heater etc. You can unplug the glow plug relay and use ether, if you must.

If i have misread or misunderstood any post, I apologize, I quickly read through this thread (I have not visited in a while)
If any of the above information is not true then the advice should be disregarded.
I hope you figure out your problem soon.

It won't help if I sent it direct to you, but I have a spare ECM as well, with the stock tune on it that I would be happy to send to GDE for you. The reason it would need to go to them is that they can re-code the stupid security coding with your vin#, so that the ECM will actually allow the engine to run longer than 3 seconds.
You mean you can't just swap'em out? they encode the damned vin# in there,Hows the ECM know what's written on the dern dashboard!!!!!!!

I'd be shocked if it was the ECM, but at this point... I'm willing to grasp at the same straws you are. I'm NOT thinking anything mechanical anymore, the engine sounds just fine without any fuel going into it.
Would lack of compression hide the noise?

The fact that this all happened at speed and with the engine running normally prior... Says that if there had been a loss of compression, you would have found the reason already - Probably via a newly-installed inspection hole in the side of the block. Since that hasn't been found, I'm gonna pull my money from the "messed up internals" column. The odds are too long on that now.
I like your thinking here.

I realize it has been a VERY long time since we talked about fuel as a problem, but did you ever set up a dedicated "IV bottle" direct into the CP3 and give that a try? With fresh and shiny injectors, it will take a lot of cranking to clear the air from the fuel rail, BUT I think this might still be a worthy endeavor IF you hadn't tried that before. The RPM changing when you unplugged each cylinder is interesting - Rising RPM would (to my thinking) indicate that the cylinder is now not fighting to compress anything other than air (liquid doesn't compress, but if it was fuel it should go boom) and so the engine is able to turn easier without that resistance. Each cylinder should have been injecting fuel, and unplugging the injector should make the RPM dip, not rise.
I never did the IV bottle,but I did do a good visual inspection with fresh fuel,and the papertowel test.That stuff will burn forever if you let it.

That just still makes me wonder what is in that rail. Yet the other side of the argument is that the rail feeds all 4 equally - So how would #1 be able to run at all? When you unplugged #1, the engine ran like CRAP. Obviously #1 was doing the lion's share of the work, but the engine STILL maintained operation, right? If the two (assuming for a moment that only one cylinder is actually failed) remaining cylinders are only 90 degrees apart in sequence, then the idle would be VERY uneven.

Never mind - I don't know where I was going with that reasoning anymore, I can't figure out a logical way to eliminate any of 2, 3, 4 from the problem list. LMK if you want the ECM, or if you want to wait for the compression test. I also have a mostly-complete wiring harness, I removed the two airbox connectors for my own CRD. Everything else is still there, if you figure out that you need that. The two connectors are easy to replace.
Thanks for being such a help,and for continuing to strawgrasp for me Jim.I appreciate you and your willingness to help solve this gremlin.

Bub,

Here is the best way to test the continuity of the injector wiring:

First, you need to disconnect the larger connector from the ECU as this contains the pins to the injectors and you may want to disconnect the battery as a safety precaution.

Injector #1 pin1 to A25 and pin2 to A74
Injector #2 pin1 to A02 and pin2 to A49
Injector #3 pin1 to A01 and pin2 to A73
Injector #4 pin1 to A26 and pin2 to A51

On the bottom of the Bosch connector the first row labels pin#1 and pin#24, then on the fourth row the label is pin#73 and pin#96, you will need to count to find the right pin. Make sure to use a small sewing needle to push into the connector pins when checking continuity as the multimeter will most likely not fit without spreading the pins. If these do not good continuity then the wiring is at fault. We have also seen some occasions where the continuity is good, but the wire cannot handle the current flow due to a pinch in the wiring where most of the copper strands are broken and only a couple remain.

I don't believe the compression tool we have is going to be beneficial to you until I can get a good pressure gauge ordered for it as it was not part of the dealer tool kit. A wine cork or rubber plug will work just fine for obtaining the info we need. Start with the first cylinder and plug it while cranking the engine, you should get a rush of air pushing past the plug during the compression stroke and on the next rotation the exhaust valve should be open so zero or very little air pushing against the plug. On the downstroke the intake should open and not have much of a vacuum on the plug. You should mark the crank to easily tell where it is in the cycle. If any of the cylinders act differently then we most likely have a failed rocker arm somewhere. Feel free to call if needed at (248)977-9531

For your information and in case all of you weren't aware this little tid bit of information, but Keith of Green Diesel engineering and his engineers, worked with Daimler Chrysler in the development of our Jeep Liberty CRD.

He knows a few things about our vehicles and has a direct connect to Chrysler and VM Motori via a Hot Line.

He’s a good friend to have on speed dial and I am sure he regrets giving me his number by now.

Oh come on BUB..... you're whimping out on us : ).... Hurry up and get it done.