Been through a bunch of troubleshooting and currently posting on 3 other LR forums but without much luck.

Quick and dirty - no spark, no fuel. '99 LR Discovery II 4.0 gaser 210k. mi

Highlights:
Friend's truck - intermittent miss/stall w/ codes for misfire on 1,4&7. Since they are all on one coil pack, I replaced it (both actually). Ran perfect on the drive home. Next start, fired, stumbled and stalled. Hasn't started since. No codes stored/pending

Double checked all work - good.

Replaced crank position sensor - still no start.

Fuel pump relay does not get switched ground from the ECU. Coils have 12v, but little to no spark (assuming not getting switched ground from ECU here either).

The question I can't get answered is if I'm getting a RPM reading, isn't the ECU seeing the crank sensor? Anything else that would mimic a dead CPS other than a bad ECU?

two other threads with more detailed info:
Crankshaft position sensor questions - Land Rover Forums : Land Rover and Range Rover Forum
Crankshaft position sensor questions - Land Rover and Range Rover Forums

 

From the RAVE. Read it carefully, especially the last paragraph.
I've attached the relevant section all about CKP

 

I've read through it multiple times - I have the hard copy manual and a downloaded copy so I can refer to it wherever I am. Thank you very much though - I'll take any help I can get! The sensor was replaced with no change. In addition, it was running perfectly when it was turned off. It sputtered and stalled on the next start.

My issue is that I can read the RPMs while cranking through OBDII so I think that tells me the sensor is good. We were hesitant to replace it because of this, but it did fit the other symptoms:

In the event of a CKP sensor signal failure any of the following symptoms may be observed:
l Engine cranks but fails to start.
l MIL remains on at all times.
l Engine misfires (CKP sensor incorrectly fitted).
l Engine runs roughly or even stalls (CKP sensor incorrectly fitted).
l Tachometer fails to work.
l Flywheel adaption reset – ferrous contamination

Right now I can only think of two causes - dead ECU or a physical problem with the sensor wheel/teeth that is preventing the sensor from detecting TDC.

 

If it is a D2 there are no teeth. The reluctor disk is a drilled affair.

Immobilization?

 

I have a sneaky feeling the spacers were replaced incorrectly on the CKP. This will prevent the sensor from working correctly even if the ecm sees it there.

That's the first thing I would do. Pull the sensor and check the spacers.

Actually, the first thing I would do, because it takes 5 seconds, is swap the fuel pump relay with the washer relay next to it. Just to positively eliminate that relay as the problem.

Then I'd check the CKP spacers.

BTW, if you decide to disconnect the CKP wire (which I don't think is necessary), do yourself a favor and buy some long handled needle nose pliers. I think mine are 12" pliers. Use the pliers to grip one part of the connector while using your hand on the other part. This frees up a lot of space to work and saves much time and energy that are otherwise spent cursing at the top of your lungs.

I've ended up using those pliers many times on this truck after working on cars for 15 years and never needing a pair. I now call them my "land rover pliers".

 

I verified that the sensor was installed correctly (sensor, spacers, nuts). I really didn't find it too hard to replace other than not having a 7mm socket with me (working in buddy's garage where it died). A 1/4" drive ratchet with a swivel did the trick. Both the old and new sensor are exhibiting the same symptoms and both show RPMs via OBDII scanner while cranking.

Swapping the relay was one of the first things I tried (also the one that powers the ECM). The relay has ignition switched 12V to it, but the ground does not get sent from the ECU. I ohmed out the wiring from the relay to the ECM and it all checks out, along with the ground connections to the ECM. I jumped a ground to the relay and the fuel pump comes on with the ignition - still no spark though.

Good to know on the reluctor. I saw this in the manual: "air gap between the tip of the CKP sensor and the passing teeth of the reluctor ring" The manual did refer to "Flywheel adaption reset – ferrous contamination" as a problem associated with the sensor.

As far as the immobilizer - I've armed/disarmed the alarm with the remote and locked/unlocked 4x with the key in the drivers door. There are no indications on the dash that the alarm is a problem and it did actually start, then sputtered and stalled.

As far as I can tell, the problem has been around for about 2 months and progressively got worse. At least, I'm hoping that's the case. I'm not giving up on it yet! Thanks for the help - I do appreciate it.

 

I just got a suggestion on another forum: "Bypass the inertia switch. See if that allows it to start or impacts the lack of spark. Rule out the easy/cheap crap first before replacing the ECU. My switch appeared to be functioning correctly, flashers on when disconnected and tried to start. Truck would not start when switch was connected, only when bypassed."

I had disconnected the inertia switch while ohming it out and accidentally tried to start it with it that way. The 4ways came on while attempting to start. Took a little bit to realize that the disconnected inertia switch was the cause. I took that as proof that the switch was working, but this shows otherwise. Easy to try...

 

Hmm, it sounds like you've been pretty thorough. It can't hurt to bypass the switch, maybe you'll get lucky.

ECMs are only ~$50-$100 on ebay, so it isn't that huge of a gamble. And ECM failure is rare, so I doubt you'll get a bad one.

 

I like to think I have been... Trying to rule out one thing at a time. Did I read correctly that I need a matched ECU/Alarm unit?

So far the only ECU failures I've come across have been water related. No signs of moisture at all anywhere near this one.

 

I had the transmission ecu in my volvo die for no reason at all.

So it does happen.

The good news is that ebay has made it clear that ecu failure is rare and the market is generally glutted with them, so the cost for a used ecu has dropped enormously over the last 15 years. Back when I was a mechanic in the 90s, most used ecus were close to $1000, and it was a good deal when we found a local electrical engineer who would repair them for only $500.