Do you recall the part number of your fuse box? the one removed and the one used to replace it? and where you got it from? I've been looking for one during the past two weeks with no luck yet; my truck cranks and hasn't been able to start for over 4 months already, so last place we got left to look is the fuse box being faulty. Let me know, thanks!

 

...I feel your pain! I've been without my Disco for over 4 months and still cranks but no start. Replaced all you mentioned, been in three different shops, thankfully the last shop I visited has gone over the moon trying to figure out the issue, no luck yet, but refuses to give up! has ruled out many things and still scratching his head; so we are looking into the under dash fuse box being the culprit, since pretty much everything else that could contribute for truck not to start is working or has been replaced, from fuel pump to battery. In my case truck simply shut off while waiting for a green light ...no signs of anything going or about to go wrong, no warning light, no codes ...it simply died on me. The day I had it towed to shop where it now is, owner told me once they got it off the tow truck, they tried jump-starting it and it ran, so he personally drove it into the shop, but after shutting it off, it did not run again, so he figured it might be a fuel related fault ...he ended up making it run again a couple of weeks later, again while checking fuel system, but finally gave the fuel system a clean bill of health and moved on to look elsewhere for the fault... so after many tests and ruling outs, we are now looking at the fuse box. I'll keep an eye on your post to see how it goes... and I'll report back in case my comes back to life and my experience can be of help. Good Luck!

 

I'll be picking up a used interior fuse panel from a local who is scrapping their Disco out to Craigslist sometime either tonight or tomorrow and will report back.

I also have a used ECU and BCM in my storage unit a couple towns over if this doesn't work, just to rule things out that are simple.

I forgot until literally just now that I believe the coolant temp and trip MPG on the UltraGauge read "Err" when this all transpired. I don't know if that's of any significance.

 

I'll appreciate that "I BRAKE FOR CATS", thanks! I've had no luck yet getting the right one (YQE000250 or YQE000410) after many calls and messages. As per the ECU & BCM, if I recall well, my mechanic already ruled them out, but I'll refresh that with him, thanks. I'm also planning to visit a junkyard nearby tomorrow, I received an email that a similar Disco went in, although is being raining lightly here, hopefully it won't be flooded there tomorrow. Fingers crossed, and thanks again! ;-]#

 

Replaced fuse panel with no luck. No change in symptoms.

I did get a random pending P1668 but it hasn't come back. I used to get that code every time I started the engine and I believe it was related to my house battery setup (disconnected currently during all this).

I also noticed my UltraGauge reads engine temp fine when key is in II position but when I crank it and stop the engine temp and MPG read "Err".

 

As per the Fuse box you swapped, can you tell us the part number of the one you took out of you truck, and the one you replaced it with?

I ask because I'm on the same task, but it has been HARD finding the one I need (YQE000250), and although I was told to replace it with the same one, or YQE000410 that superseded it, I pulled out a YQE103830 from a similar truck with no SAI and will take it to my mechanic tomorrow and see if at least the truck starts.

Nothing tried so far has worked,, so we'll give this a try.

My truck is a 2002 SII SE with SAI

 

Will keep posting updates until this is solved.

Spark tested good with inline spark tester.
Fuel measured over 50psi while cranking.
Interior fuse box changed with no luck.
Inertia switch jumped with no luck.
New copper plugs and fuel pump relay unplugged, no change.
No visible water damage at ECU.
No abnormal alarm light on dash behavior AKA not likely immobilized(?).
Service Engine Soon light is on during startup indicating ECU is communicating properly(?).
Relays swapped and all fuses checked, no change.
Grounds checked.
Alternator connection checked.
Battery is new and gets charged overnight when I'm not working on it, so I have full charge every morning.

A few notes:
One of the melted and severely damaged wires sent power to I believe the fuel injectors. I have repaired this but could a short in that system cause an ECU fault?

I occasionally get what I believe sounds like a backfire in the exhaust when cranking. When I say occasional I mean like maybe once a day randomly when trying to crank.

I asked further up but never got an answer, there is no grinding or mechanically concerning noises when cranking, nor when the engine cut out. Since the timing chain was mentioned, would there have been a noticeable engine clatter associated? And is there an easy way to check this?

Any help is greatly appreciated. I've seen numerous posts with the same predicament but there are so many that don't follow up with the solution! The ones that do, I've already tried.

 

Have you run a compression test by chance?

 

I'm happy to report that after swapping fuse boxes on my Disco, mechanic called this afternoon to let me know it is running again, after almost 4 months of issues, but all seems to be OK now. My fuse box was a YEQ000250, but I used a YQE103320 that I pulled from a similar 2002 Disco parked in a nearby junkyard yesterday morning. Hopefully this have solved my issues, which seemed to be more or less like yours. My mechanic checked all things you mentioned as well; initially he was focused on the issue being gas related, since he was able to crank it up when tow truck left it, and drove it inside his shop, but never ran after that. So after replacing fuel pump and checking all players in fuel system, he gave it a clean bill of health and moved on to next possible culprits. Two to three weeks ago, after having checked everything he could think of to prevent it from starting, he figured it must then be the fuse box, since everything else checked back as working or having been replaced. Getting a donor fuse box became the issue, and finally found one that we did not know if it was in working condition, besides being a different part number from the original one, but it turned out to work, since he reports it is up and running, so planning to pick it up tomorrow and test it myself. Fingers crossed. I'll try an have him read this post tomorrow, and see if you're missing something he looked I mine, because like I said, the symptoms you describe are just like what I went thru.

 

...obviously you must had already replaced the Crankshaft Positioning Sensor, but what about the CAMSHAFT one? ...I don't see that in your report, and these he also checked/replaced on mine.