Land Rover discovery 3.0 diesel cam/crank sensor fault

Hi, I'm after some guidance with a job we have in at work.
We have a Land Rover Discovery 4 with the 3.0 Diesel engine, the car came in running but knocked and had low oil pressure. My college rebuilt the engine but after refitting it, it would not start and it flagged a "cam sensor a out of range/performance" code
I put the scope on the cam sensor signal wire and got a perfect looking 0-5v square wave. Next I went to the crank sensor signal wire and got a steady 5v with no wave form.
We removed the engine (engine or gearbox had to be removed to replace the crank sensor) and found my college hadn't got the crank sensor seated properly and there was a huge air gap, he apparently put it right and refitted the engine.
The car still would not start though and had the exact same code again.
I scoped the crank signal again and this time found a weird pattern (I'll post pics) to me it looks as though the air gap could still be too large? But my college is having absolutely none of it and he is convinced it's a cam sensor problem.
One thing I'm a little unsure of is the signal on the crank sensor is a constant 5v but when I plugged in a spare crank sensor we have lying around (plugged in but not fitted to the engine) the signal is 0v? Either way I'm thinking the engine has to come back out but really don't want to call this wrong as I'll never hear the end of it.
Please could anyone give me there opinion on the waveform. It was taken on our snapon Zeus scanner/scope and also includes a image of what it should apparently look like.
Thanhs in advance guys

Hey Ian85! Wish I had a known good waveform to back up what the Zeus is telling you. Another engine the US market will never see.

But, even if the Zeus is wrong, that still doesn't look like any modern CKP signal I've ever seen. I agree that there's likely an air gap problem, OR something happened with the installation of the reluctor wheel. Is that the flexplate/flywheel in this case, or something else? Could you post a zoomed out view of the waveform, for a better idea of a 720 degree cycle of the engine?

One thing I'm a little unsure of is the signal on the crank sensor is a constant 5v but when I plugged in a spare crank sensor we have lying around (plugged in but not fitted to the engine) the signal is 0v?

What happens if you wave something ferrous in front of the spare sensor while it's plugged in? That'd give me more confidence in the wiring. Even better if there's scan data PIDs to observe while testing the sensor.

Hi i maybe slow, but why not check the crank/cam powers and grounds at the pcm which is located behind the battery,to see if they are leaving the pcm,i,m sure theZoose has the pin out for the pcm connectors,

If engine has been removed by someone else first thing id be doing is checking power/earths for voltage drop at the battery, chassis, engine etc

Hi guys sorry about the delay to respond, Iv had a nasty eye injury.
Anyway Iv been back on the landrover and thought I'd give an update.
The live data does show rpm as the engine turns over, the rpm shows around 250 when cranking(seems a low number but doesn't sound slow?) if you unplug the crank sensor the rpm reads zero.
My boss had a auto electrician look at it while I was away and he has condemned the cam sensor.
I'm still not convinced as the scope shows a good looking 0-5 waveform from the signal wire(at the ecu).
I still think we have a crank sensor signal problem and put the rpm pid down to a messed up signal. Anyway I'll be happy to be proved wrong and we have a new cam sensor coming tomorrow so we will see??
I also checked the ecu powers and grounds as suggested but they were all good.
I'll let you's know what happens with the new cam sensor tomorrow.
Thanks

Sorry Tyler, The reluctor wheel has been changed, it's knocks onto the end of the crank and does have to be timed, the mechanic did have the timing pins and and has done several before with no problems. If we end up removing the engine again we'll replace it again as a precaution.
As for the other crank sensor which showed 0v out the engine, I waved a bolt in front of it and couldn't get it to show anything on the scope, which is strange, but I don't know where this part came from and it may well be broken? Or am I missing something?
Anyway thanks for your help mate

Be interesting to see if the new cam sensor fixes it, not convinced it will if it ran before and you say it has a nice square wave. Id try check timing if it is possible before pulling engine out again. 250rpm on the live data sounds good for cranking speed.

Also very interested to see if the cam sensor fixes it. Thanks for keeping us updated! Do you happen to know if the auto electrician saw the same waveform you did?

I still can't make sense of the waveform you posted. Even if CKP is producing the correct signal, why are there seven pulses with the CMP signal is high? :huh: I mean, we know OE's can make the signals look like whatever they want, but it's still screwy.

Sorry Tyler, The reluctor wheel has been changed, it's knocks onto the end of the crank and does have to be timed, the mechanic did have the timing pins and and has done several before with no problems. If we end up removing the engine again we'll replace it again as a precaution.

No worries, thanks for the clarificaiton! I still wonder if something happened to it during service, like a magnet got waved around near it or the like. Just speculating.

As for the other crank sensor which showed 0v out the engine, I waved a bolt in front of it and couldn't get it to show anything on the scope, which is strange, but I don't know where this part came from and it may well be broken? Or am I missing something?

Nope, you didn't miss anything - that should have worked. :lol: As long as the bolt was ferrous, anyway. As long as the wiring is good, that sensor is junk!

Hi guys, well we've finally got to the bottom of this.
The cam sensor change didn't do anything so we re checked the cam timing and guess what the crank was 2 teeth out! Our mechanic claims that he pinned it all up and Iv got to say it's very unlike him to make such a simple mistake especially as he's already double checked it.
Anyway it's sorted now which is the main thing as the customer is understandably getting very impatient.
So thanks to everyone for your advice and if nothing else at least we now know the crank signal was normal.
Cheers guys

Glad its sorted. Thanks for letting us know.

Ian85 wrote: The cam sensor change didn't do anything

Welp, saw that coming, eh? :silly:

so we re checked the cam timing and guess what the crank was 2 teeth out!

Didn't see that part coming. :ohmy: So that CKP waveform IS good. Color me surprised!

I don't suppose you got the chance to take another cam/crank waveform afterwards? No worries if not, just curious about the relationship. Do you think the mechanical timing being out was causing the no start? Or was it the cam and crank being out of sync? Because the RPM signal suggests the PCM had enough timing information, but who knows what it was actually doing with the injectors.