I just bought a 97 Disco which will crank but not start. No fuel pressure at the rail and no spark — vhich sounds to me like a bad crank position sensor.
I cured a friend's no fuel, no spark, no start problem on his 98 Disco earlier this year by replacing his crank position sensor, so I have now tried to do the same on this one. On his, the small bolts (7 mm head, 5 x .8 mm threads) broke free and came out just fine.
On mine they both sheared off - although fortunately not flush with the the bell housing surface. With the sensor removed, I now have about 1 inch of thread on one to work with and about 2 inches of thread on the other. I've cut away the inner fender shroud, so I've got a fair bit of access.
Anyhow, after several shots of P-Blaster, judicious application of heat with a mini-butane torch and a lot of very cautious twisting and turning, I have not been able to get either of these little so-and-so's to come out. They don't look to be corroded at all and I can get both of them to turn further in quite freely, but neither one will come out.
My suspicion is that the inboard ends of these bolts have became burred somehow (by contacting the flywheel?) and therefore won't thread back out through the front face of bell housing.
I'm toying with the idea of cutting them off so they're about 3/4 of an inch long, and using a Dremel to cut a slot in the accessible end and then using a small screwdriver to thread them in until they come out the other side (I'll try to catch them as they fall out with a magnet) but I'm wondering whether there's enough clearance between the bell housing and the flywheel to make this feasible, and what might happen if I don't manage to catch them and they fall to the bottom of the bell housing.
I'd be very glad to hear anyone's thoughts on this, particularly if anyone else has found himself in this situation and has managed to come out of it successfully.
Cheers
Bryan Colleran
(my first posting on his forum)

 

Man that sucks.
I agree with the bad crank sensor if you tried resetting the inertia switch first.

 

Hurray! I've now managed to get the new crank position sensor mounted.

After a lot of fiddling, I decided to drill out the mounting hole in the new sensor and in the sensor mounting bracket to 8 mm (original size 6 mm). I then used a small lathe to turn up 2 mounting fittings with an 8 mm sleeve tapped internally to 5 x .8 mm.These thread onto the remaining stubs of the original mounting bolts and have a 10 mm shoulder that draws the sensor and the plastic cover/shroud doohickey up tight to the bell housing.

If anyone ever has an interest in or need for this bodge, please let me know and I'll be glad to forward a sketch or two. It saved me from having to drop the transmission and pull the bell housing in order to be able to drill out two broken 5 mm bolts.

The new fittings are done in stainless and I've liberally CopaSlip'ed the threads, so if I ever need to get the sensor off again (here's hoping I won't) it shouldn't turn into such an ordeal.

Anyhow, with new crank sensor in place, i've now got fuel pressure at the Scvhrader valve on the right injector rail, but still no spark. This could be the cam position sensor I guess, but it seems unlikely to me that 2 sensors would fail simultaneously.

It's more likely something to do with the ignition lock, I think. Here's why: The key is very hard to turn in the ignition switch. A liberal application of dielectric grease a lot of turning on-off has now made it possible to get the key out of the ignition without too many facial contortions, and (as a bonus) the mysterious unopenable fifth door now opens (and shuts) freely. The key i still hard to get urned initially, and the starter still does not engage until 3 or 4 seconds after the key is first turned fully clockwise to the 'start' position, but after a couple of off-on repeats the starter then responds immediately to the key being turned fully clockwise. So something is clearly not right there.

I've got a new ignition lock assembly coming (thank you, eBay), so Ill see what (if anything) this changes. I've switched out both the ECU and the multifunction relay that's mounted on the fender ahead of the ECU with units from a working Disco and still get fuel pressure but no spark/no start.

Does this sound familiar to anyone. Any helpful insights?

I've been fiddling with friends' and neighbours' Discos a fair bit over the last year or so (I'm a long-term Series Rover owner/rebuilder), but have only succumbed to temptation and got my own Disco in the last week. I've already found this forum to be tremendously helpful, and I'm hoping that, in time, I'll be able to post some things here that may prove somewhat helpful to others.

Cheers

Bryan Colleran