QUESTION
I have an erratic misfire problem with my 1968 Lotus Elan +2
Starting the vehicle from cold is fine but now and again the engine misfires and I can see the tachometer needle bouncing around
Some times the engine will die completely and will refuse to start
Can you tell me what causes this and how to rectify the problem?
W.H. - Kirrawee, New South Wales
ANSWER
What you describe is typical of a faulty anti-theft switch interrupting the supply to the ignition coil.
In the early Lotus Elan +2 there is a simple slide switch located in the glove box that allows the battery feed to be disconnected from the ignition coil.
This switch is a change over switch and when armed, the electric horns are connected instead of the coil.
This switch is well known to cause ignition failure problems when the engine dies for some unknown reason.
The tell-tale symptoms of the switch causing problems is, the ignition system mis-firing and the tachometer being erratic.
To check if the switch is faulty, simply by-pass the switch so there is a permanent connection to the HT coil and the misfire problem will disappear.
Unfortunately the original switch is of a cheap construction (with the metal casing crimped over at the back) that does not age well.
With use and constant vibration, the switch body becomes loose and the contacts become intermittent.
This switch is useful for its anti-theft function but it is recommended that it be changed for a sealed component that is rated at 10 Amps continuous.
For some unknown reason during vehicle production this anti-theft function was deleted on the Lotus Elan +2 S130/5
Copyright © 2012 Lotus Marques
I have an erratic misfire problem with my 1968 Lotus Elan +2
Starting the vehicle from cold is fine but now and again the engine misfires and I can see the tachometer needle bouncing around
Some times the engine will die completely and will refuse to start
Can you tell me what causes this and how to rectify the problem?
W.H. - Kirrawee, New South Wales
ANSWER
What you describe is typical of a faulty anti-theft switch interrupting the supply to the ignition coil.
In the early Lotus Elan +2 there is a simple slide switch located in the glove box that allows the battery feed to be disconnected from the ignition coil.
This switch is a change over switch and when armed, the electric horns are connected instead of the coil.
This switch is well known to cause ignition failure problems when the engine dies for some unknown reason.
The tell-tale symptoms of the switch causing problems is, the ignition system mis-firing and the tachometer being erratic.
To check if the switch is faulty, simply by-pass the switch so there is a permanent connection to the HT coil and the misfire problem will disappear.
Unfortunately the original switch is of a cheap construction (with the metal casing crimped over at the back) that does not age well.
With use and constant vibration, the switch body becomes loose and the contacts become intermittent.
This switch is useful for its anti-theft function but it is recommended that it be changed for a sealed component that is rated at 10 Amps continuous.
For some unknown reason during vehicle production this anti-theft function was deleted on the Lotus Elan +2 S130/5
Copyright © 2012 Lotus Marques
