as above please

 

the igniter or the coil? The igniter is basically just a switch.... the secondary coil(s) in the coilpacks produce tens of thousands of volts

 

some more explanation... a basic ignition coil works like this:



there is a primary coil, which has wider diameter and fewer windings. On a modern car this is controlled by the computer in some way (as opposed to a completely mechanical distributor system.

It's the old V=IR , voltage = current times resistance. So the computer switches the igniter which switches current on through the primary coil. When the coil is turned off, high voltage/low current builds in the secondary coil (the narrow one with more windings).



on the FD, which is a wasted spark system on the leading, both leading plugs fire at the same time. There is nothing unique about the FD leading ignition system.

 

so here is the basic architecture of a wasted spark system on a Japanese car using an external igniter box:



this is a Toyota inline 6. the computer takes the G and NE signals (FD has these sensors) and uses it to determine when to fire the plugs. Then it sends a signal to the igniter box.



in this example of an igniter box you can see that it processes the trigger signal from the computer and activates the primary coil windings in the coilpack(s). it then sends a confirmation signal back to the computer so that it knows when the spark has been fired.



the signal from the igniter box activates the coilpack, similar to above.


Now that you have a better idea of how the ignition system works: assuming there really is a weak spark, there are a bunch of things that could be bad besides the plugs. The wires could have high resistance across them. The coil packs could be bad. It's possible that there's something wrong with the igniter but that's not a common problem, nor are crank angle sensor problems common on these cars. All bets are off if you have hacked up wiring or a poor condition harness on the car though.

Download the workshop manual and use the diagnostic procedures there. Look through the engine electrical section and the fuel/emissions control section.

 

The coil saturation and trigger (igniter output) should be around 400 volts; typical of about any modern ignition system.

 

Our ignitor is not a CD unit but a transitor switching device that mimics the operation of distributor points: on and off 12V to supply current to the coils.

Read up on how it works here:
http://en.wikipedia.org/wiki/Induction_coil

 

Big Jim and the twins got arc welded to the fender one time messing with those ignitor leads. I do have a twin power however - that's probably the difference....

 

thanks peaps lots of help
i was after cewrx7r1 comment of 12V switch
just so i don't blow my scope up it can only handle 50V

 

is the fd3s stock coils 400v or over and how many amp
any exact figures