I took my coil off today to try and find a little problem ive been having with my car cutting out randomnly when hot. So I wanted to test for a spark, I hooked up + 12v to one pin and -12v to the other and was expecting to get a nice spark out the other side (where the high voltage lead plugs in) against ground but i got nothing. I then removed the -12v ground and tested to see if im getting a voltage out the high voltage side, and im getting continuous 12volts ?? This isnt right is it?? I then hooked up the ground again (to the low voltage side of the coil) and again measured the voltage and theres no volts coming out? I know the spark is meant to happen when the circuit is broken, but i dont get high voltage, just 12v?!?!?

Unless you want to blow your meter up, i wouldn't be trying to measure anything on the high voltage side! The output will be somewhere around 30,000v! Coils usually have an internal connection between the primary and secondary windings. This is why you will see 12v on the HV side when you apply 12v to the primary winding. When the power transistor opens, the collapsing magnetic field produces a large voltage pulse on the primary, which is then multiplied by the turn ratio of the coil to give an output around 30,000v. Simplest way to test the coil is by substitution......with a new one.

and randomly cutting out when hot.. sounds alot like CAS to me..

Id say CAS, they usually cut out randomly when the motor is hot.

cas, dizzy, leads, its all been replaced

What about the coil transistor on the side of the dissy?

got replaced with the dizzy! Just before the car cuts out, it give me a warning, which is the tacho going haywire up and down to redline and back instantly.

Quote: Originally Posted by airbagsVL got replaced with the dizzy! Just before the car cuts out, it give me a warning, which is the tacho going haywire up and down to redline and back instantly. that will be cas related