I own a Eunos Roadster which has always started and run fine. When I bought the car, it came with a small fob for an aftermarket immobiliser.
I’ve had an issue recently where most of the time when I insert and turn the key, the lights on the dash come on but the car does not start. However after 10-30 attempts it will crank and start. When it does crank, the engine starts without any issue so I am assuming the issue is a failing immobiliser.
I’ve removed the panel below the steering wheel to look for the immobiliser but have had no luck. I did find a small red LED that I believe is part of the immobiliser system but cannot see where it leads. When I insert and turn the key, the LED flashes rapidly.
I’m not 100% certain that the immobiliser is the issue but it seems like a good place to start. Any advice would be much appreciated.
My immobiliser failed. I thought I could track back the wiring and remove it all. The wiring will be all black. There might be bodged soldering into the loom. It will tap into the fuel pump, which is a yellow relay on the drivers side, and ignition switch. The black box, if it was installed correctly, should be tucked under the ECU. I gave up and paid a garage £100 to remove and make good. If anything went wrong, I can blame them.
But your other potential issue is the ignition switch. MX5 ignition switches are known to fail, often due to too many keys on the key chain.
Just incase this helps anyone in the future; the problem was actually a partially blown 80A main fuse. The fuse looked intact but the plastic on top had melted. After replacing it the car starts fine.
Why did the fuse blow? Usual reason is someone tried to jump start the car with the terminals the wrong way around. The other reason is you have a short someplace. Check alternator wiring, check ignition switch etc