Strange Discovery 1 immobiliser problem

Long time lurker on the forum and have found some really useful information, so thanks to everyone. I have a late V8 Disco 1, registered December 95 and need some advice please. I have done a search but the results seem to centre around bypassing the immobiliser rather than addressing the problem that I have where things seem to have got out of synch.

Over the last couple of weeks, I have replaced all of the usual front and rear suspension bushes, A frame ball joint, rear discs and pads etc and the result was something that went where I wanted it to go rather than having a mind of its own.

Next step was to drag out the soaking carpets and try to find the leaks. I removed seats, card panels under the dash, centre console, carpets and soundproofing and then drove the car two or three times with no issues.

Next stage was to remove the front bumper and wings to get to the A pillars and inner wings. Having sorted the leaks (water tested and nothing came through) I started to refit the wings etc.

Just before I finished this evening, I thought I would run the engine for a few minutes.
There lies the problem. It turns over fine but will not fire. Everything points to the immobiliser having got out of synch with the car.
I have checked to see if I have disturbed or unplugged anything but there's nothing obvious. I have never had a problem with starting or with the immobiliser before today.

When I lock the car with the fob (two button), the light in the centre of the instrument panel flashes and the indicators flash several times. When I unlock everything seems normal except the red light isn't illuminated on the dash. Normally it is solid red until the engine starts.
When I turn the ignition on I can hear the fuel pump running for a few seconds and then it stops when the pressure is up. Engine turns over fine but doesn't fire and all other circuits appear to be working.

Any suggestions please on where to look next?

Perhaps too much information!

Under normal circumstances what would be the likely cause of the indicators flashing three times and the dash light flashing rapidly for a few seconds when the car is locked?
Would this indicate a fault with the immobiliser or something else?

I assume that a problem with the 'Spider' would result in a non start with no external signs of a problem. This is why I think that I have somehow got the immobiliser out of synch with the car.

Have you tried disconnecting battery and leaving it for a few hours for everything to flatten down then reconnecting.Just make sure that you put the terminal back in one clean go if you get my meaning.

Sounds normal, a rapid flashing of the dash indicator for around 10 seconds then changing to a slower flash after locking also the indicator ceasing to be illuminated when first unlocked indicating the vehicle is remobilised but if you fail to start the engine the indicator it will then start flashing along with a key/car symbol in the dash display.
If the spider was faulty you wouldn't be able to crank the engine.
You will find all the info in the owners handbook.
As for "immobiliser out of synch with the car".

discool said:

As for "immobiliser out of synch with the car".

Click to expand...

What I meant was that the car seems to think that it has been locked with the fob and unlocked with the key. I cannot seem to get things back into order so that it recognises that it has been locked and unlocked with the fob.

All this A-pillar and inner wing work suggests to me that you may have disturbed an earth, I'm not even entirely sure where the earths are on a disco but generally thats where main earths live!

Silverbeard50 said:

What I meant was that the car seems to think that it has been locked with the fob and unlocked with the key. I cannot seem to get things back into order so that it recognises that it has been locked and unlocked with the fob.

Click to expand...

Have u tryed to re-synch the fob with the alarm ecu by pressing the fob lock button four times something that is required after a battery has been disturbed.

Thanks for the advice. I tried all of the suggestions and nothing worked. I rang the local LR dealer and got the origianl key and immobiliser codes and was then able to reset the immobiliser using the driver's door key. All seems well now and it starts with no problem now.

Famous last words! The problem persisted and so I fitted the spider by pass loom and all seemed well for a few days.
However, the non start problem became more frequent so I put the car into a Bosch injection and ignition specialist whilst I went away on holiday asking them to investigate the problem and check over the fuel injection to identify the cause of a slight misfire on idle.
They changed the advance mechanism on the distributor and declared everything fine but asked to keep the car overnight to make sure the cold start was good. Next morning they couldn't start the car and said it was turning over very quickly. I had changed the oil and filter recently but they suspected that the pressure was insufficient to make the hydraulic lifters work on cold start. They changed the oil and filter again, another overnight stay and then they changed the cold start temperature sensor to 'make sure all was well'.
The car was returned to me and drove very well from the warm start but the next cold start produced another non start.
I have done some basic checks including a compression test which gave between 160and 180 psi on all cylinders. This, I presume, confirms that the lifters are working from cold otherwise there would be no compression. The plugs came out damp and I could smell fuel when cranking for the compression test, so fuel is getting to the cylinders.
I have checked for a spark at the plugs and this seems to be the problem. The spark is intermittent at best; nothing then a couple of big fat sparks, then another gap then a weak one or two, then nothing.
I am assuming that the distributor is fine as it's just been checked over. Could the coil be failing on cold start or is there something simple that the wise minds on here can point towards please?

Coil could be failing so could you ignition amplifer which I would change first if I had a problem. Your leads and coil top connections ok??

When I got the car last November, the leads were a real mix of different types so I bought a good quality set and replaced the distributor cap with the right one (confirmed by the Bosch specialist).
Coil and amplifier sounds like the next best step; is it OK to buy from Paddocks/MM 4x4 or should it be a particular make?
Thanks for the advice.

Sounds to me like everyone is buggering around pointing sticks at things rather than doing a decent,structured diagnosis.
I'd find a decent garage.

Update. I have cleaned and checked all of the connections from the distributor to the coil and amplifier. In doing so I found that the coil and amplifier have both been replaced with Intermotor brand components at some time.
There are also two very small black plastic blocks in the wires to the coil from the engine loom. They have spade connectors either side and both were very dirty and corroded.
Unfortunately cleaning and spraying all connections with WD40 hasn't made a scrap of difference. I am still convinced that the problem is down to an inconsistent spark at the plugs.
Voltage at the coil is 11.8 volts with the ignition on and just under 9 volts cranking.
Next step is to download the Rave information to see if that gives me any ideas on where to go next apart from replacing the amplifier and coil.