Bantam 1.3 Rocam feul problem

I had a few of these. The starter solenoid wire is running in the same channel as the crank angle sensor. When the starter solenoid is energized this induces a higher voltage into the crank angle sensor wiring. Move this solenoid wire out of the crank angle sensor wiring channel. Check the condition of the main starter cable from the battery to the starter. Clean the terminals and the amperage draw on this cable. Check the earth cable from the battery negative to the body and fit an extra earth cable from the battery Neg terminal to the gearbox.