Hi all, I just picked up a 99 disco I. It's been starting and running fine until today. I pulled the drivers door panel to adjust the linkage so the exterior handle would work. I noticed that some previous owner had disconnected the door lock actuator/switch from its linkage. I inadvertantly moved the actuator and it locked, then unlocked all doors, then quit working. Anyway I reinstalled everything after making my adjustment and now the car will not start. It cranks over but will not fire. Tonite I have found the following and am looking for help:
-Engine MIL light will not illuminate when rotating key to on or start position, engine will crank over but not start.
-If battery negative terminal is disconnected and then reconnected then MIL light will illuminate and vehicle will start! However, if key is turned off for longer than 5 seconds exactly and then turned back to on or start position MIL light will not illuminate and engine will crank without starting.
I am looking for any advice especially concerning possibly removing green alarm unit. I noticed in the wiring schematics that it was apparently an option anyway. Thanks!

 

see https://landroverforums.com/forum/di...-bypass-46728/

 

Thanks Buzz but I've already checked into that. My vehicle has a different system without the "spider" unfortunately. Any other suggestions??

 

here you go.

The Definitive Alarm Spider Post - Land Rover Technical Archive - LR4x4 - The Land Rover Forum

 

My machine is a 1999 with no spider, only the "Z163" Theft Alarm Unit. From looking at the electrical schematic it appears that this unit was an option. However if I take it out will the engine computer need to be reconfigured as well for the non-theft alarm unit option?

 

From looking at the schematic attached I would say removal of the unit would be a problem, the door key tells the same unit to operate the door electic lock. See attached. Now nothing says you can't have a broken wire that make/breaks when door is opened, like on the Blue&green from the lock switch. If you have a fob, try open/close five times. Here's some notes on the dash LED, which may show you what the alarm thinks it should be doing:

 

why dont you replace the lock actuator with a working unit from a parts guy. that actuator contains the CDL or central door locking switch, which is why when i actually read your post i realized you have the same alarm system that's in the P38. If that doesnt do anything then i would attack either the BECM or passive coil. you checked the inertia switch correct?

Security and Alarm System Operation & Diagnosis on Range Rover 4.0/4.6/P38A

 

If it cranks, it's probably not the alarm causing you problems. Could be a coincidence that something else failed when you parked it. On my D1, the fuel pump failed in my garage. I drove it in with no problems, and then next day I went to start it and it wouldn't.

 

Well I've done a little more troubleshooting today.
Found that the car will start after disconnecting battery cable (same as before), or by unplugging both connectors on the "Z163" alarm unit and then reconnecting.
The inertia switch seems to be internal on the alarm unit instead of a seperate unit, could that be causing a problem?
Also rang out the harness on the drivers door switch, and actuator, both are signalling to "Z163", but not working the door locks. Also I have no key fob and the LED in the dash has never illuminated since I have owned it. Does anyone know if the alarm system sends one digital input to the ECM or is it like the Ford system where the alarm and ECM are constantly communicating?
Also, I did notice that it was simmilar to the P38 system however it uses a transponder ring around the ignition switch whereas this Disco has no ring installed and doesn't appear to use one by looking at the electrical info. Any help is good. Thanks.

 

key pulse ring was not North American Spec. Believe the alarm/ecu only communicate at certain times to re-mobilize; not constantly.