Im trying to find the test procedure to determine if i have a bad crank angle sensor or something else like the ECU on my 91 mazda B2600i 4x4 manual. I have good spark going into the distibutor but nothing at the spark plug. Have replaced cap rotor and wires and replaced distributor with a used one (supposed to be a working one though). The only tests i can find are for the ignition module, which i dont have, or for three wire connectors and mine has four. its the style of sensor that has a slotted disk. The multimeter test procedure or any other possible causes would be greatly appreciated. Thanks