Ok Im here scratching my head...I have a 99 Disco 1 with the 4.0 GEMS. Started having some running issues and it not starting from time to time. Replaced the crank sensor and boom runs like a top. No more issues. Went on a couple hour tour and it ran and started perfectly. Shut it off, came out the next morning and it wont start again. Cranks over fine, tries to catch but does not start. Strong gas smell after cranking it for a bit. I left it for a couple of days (busy) came out today and it stated no issue. Took it for a nice drive shutting it off and on a couple of times, no issue. Now to note this is exactly the same thing it was doing before I replaced the crank sensor (some days it just wouldnt start, strong smell of gas, leave it for a day or so and it would start and run/drive all day without issues). No check engine light on, recently replaced the Idle Air Control Valve and evap control valve, new plugs and wires (all in the last 30days). Any ideas from you Landy guru's?

 

How are the wires going to the crank sensor? Had to replace them because of age & heat. They were brittle and missing insulation.

 

Maybe fuel temp sensor.

 

(EVAP serves no known purpose and is best disconnected till you got it sorted)
First, are you sure you have a Disco 1? 1999 is a Disco 2, also the 4 litre engine makes me think that.

Disco 1... your ECU should be GEMS. Read faults.. Check for the security link.Why.. because if the immobilizer plays up she just may not start. And yes, this can be intermittent. Our boss has a Mexican import 1997 4.0 manual and it did just that till I replaced the 10as with another one.
If this is faulty, just relearn security. Also, reset all adptations.
Is there any dampness in your coil and injector cables. you might notice it starts fine on a dry day, but not in rain.

If it is a Disco 2 , basically do the same. Only you want to check the BCU, not the 10AS. PLUS do your EKA. Also check whether on an automatic you may have dirt in the XYZ selector.

 

Definitely not a guru, but recently went through a similar issue. Are you hearing a clicking sound in the passenger side footwell? If so, the issue i had was an intermittent relay failure. Mine is a 98, and the relay is yellow and is one of two that are not attached to anything. If this sound right ill send a picture of the location.

Rich

 

I would suspect that your issue is with the engine coolant temp sensor. when they fail it can cause the car to over fuel/starve especially at first start when the mixture is much more critical to actually get it fired on a cold engine. Do you have any way to read data? Autologic, hawkeye, etc? Even the Torque app with a bluetooth dongle can read engine temp data. With a bad sensor, when it is malfunctioning you'll either get wildly cycling temperature readings or you'll get just straight temps well below zero