2000 Disco II with 145,000 miles on the clock.

Having an issue with truck not starting. Cranks over and over, but wont usually wont start. Sometimes it will fire up and run fine, but may stall at any time and may or may not start back up. Misfiring codes present. Here's what I have done.

New Crankshaft Position Sensor, which seemed to correct the problem for about a week.

Another Crankshaft Position Sensor, just incase I had a faulty one the first time around. Problem did not change. Stayed intermittent with starting and stalling.

Next I got a new battery. No change...

Brand new Bosch Alternator...Not change...

All fuses under the hood checked and are good.

Plugs and wires are not new, but fresh enough.

Fuel pump replaced less than a year ago, and I do hear it run when the key is turned. Cycling the key 5 times before cranking yields no change in the issue so im assuming its not the fuel pump.

Tonight I actually had a helper and put a brand new spark plug in several of the Spark Plug Wires while the ole lady cranked on the DII. No spark noted and I checked 5 of them before she started complaining. Had to stop at that point...I cant take too much of that...

New starter...Since I burnt up the original cranking on it so much...

I'm thinking my next step will be to change out the coil packs. Any 2nd opinions out there? What gaskets will I be needing other than the upper intake gasket? Also any tips on this job?

 

I would think it would be kinda odd for both coils to go at the same time but, I'm sure stranger things have happened. Seems like since neither is firing the problem may be elsewhere/upstream.
Have you checked your ECM connections? and wiring harness for damage?
If it were me before I changed the coils I would check with a meter the coil harness connectors to see that you are getting voltage/signal to the coils.
Just a guess...

 

have you checked the coils to see if they are being feed power?
if you don't destroy it, you can just flip the upper intake gasket over and use it again.

 

I have not checked for power being fed into the coil packs yet because of how hard they are to get to, but I thought the same thing...Kinda strange for BOTH of them to quit on me at the same time... Is there any way to check for power to them without taking the intake apart? if I have to take it off to check them I will just replace them for peace of mind...Knowing my luck if they were fine when I checked them, one would go out on me next week...

How do I check the ECM?

 

Rave will point you to the location of the ECM. Follow your engine harness back to the main connector. Then you could first check the connection there and if connection is good there and still no start, dive into the Rave and figure out which pins at the ECM are feeding your coils and check for power there. If no power there at the pins going to the coils then you can start troubleshooting from there.

 

Use a scanner to check engine RPM while cranking. You're just wasting time poking it with sticks and screwdrivers. If it shows 0 RPM replace the crank sensor again.

 

"If it shows 0 RPM replace the crank sensor again." terrific information to know, thanks

 

If you have put in two NEW crank sensors and it didn't fix the problem then I guess they could be from a faulty lot? Did you buy both new ones from the same vendor? That would be 3 bad ones including the original one you removed, again I guess stranger things have happened.
If when you changed the first one out and it fixed the problem for a week then sounds like the problem is related for sure and originating from that area..bad crank sensor 3 in a row?, crank sensor harness connector, wiring from crank sensor connector to ecm, connection at ECM....some places to check.
I would first check with a scanner for RPM like RMT said and then go from there. If zero RPM then try cleaning connector at CPS and see if it helps....may be a bad connector or connection or a wire pulled out of the connector there.

 

I think I've fixed it. I hooked up an ODBII scanner tool and watched the digital read out of RPM while cranking the engine over. For a split second it showed 4 RPM and then went to 0 RPM, then flashed 4 RPM again when I released the key. I figured that had to be a loose connection of some sort. First place I looked was the actual CPS connector. It looked to installed correctly and plugged up, but I grabbed it and squeezed the connector shut and hard as I could with one hand. I cant be certain, but I think I felt a very faint click as if it weren't plugged up all the way. I got in the Disco and it fired right up and idled for quite awhile without any stalls. I have been letting it idle for awhile every day to see if it will stall in the driveway before I road test it, but I think I'm gonna start road testing tomorrow. Maybe I wont get stranded.

 

Been driving the Disco for 5 days now with no stalls or failed starts! That "0 RPM on the OBDII Scanner while turning engine over to confirm a bad Crank shaft Postion Sensor" is a nifty trick!