I think this PDF from Toyota will help explain the function of Toyota's igniter fairly well. You have to have some understanding of electricity, magnetic fields, etc., for it all to make sense.

http://www.autoshop101.com/forms/h39.pdf

 

Can they go bad? Yes. Its an electronic switch. Typically its an "all or nothing" but some have been known to be irratic operating only cold, only hot, and/or other forms of random operation.

I'm not a 3VZ owner but in yours the ignition pickup coil in the distributor gives the igniter a signal. The igniter is an amplifier used to trigger the discharge of battery current into the primary coil windings. The coil if functional, then generates a high voltage spark through the secondary coil windings. The high voltage energy is deliverd to the distrubutor for distribution to the individual coil wires and spark plugs.

 

Query




Just a quick question I have used a different igniter to the one previously in my car. I drive a 6 cly landcruiser and the car I got it out of was a 4 cyl Apollo. will I have any difficultys or problems? it starts fine

 

73sport, you are almost perfect with your explanation. The only exception I have with it is where the igniter gets its signal from. The igniter gets its signal from the ECM, not the ignition pickup coil. The ECM gets a signal from the distributor's signal rotor (Toyota calls it a crankshaft position sensor, but it is technically a camshaft position sensor). The ECM determines the optimum spark timing relative to the camshaft position, based on temperature, load, etc. The ECM sends the signal to the igniter to momentarily shut down the flow of battery current to the primary coil. This sudden stopage of current collaspes the magnetic field between the primary & secondary coils, and generates a need to dissipate the charge from the secodary coil's development of high voltage - which is discharged as a high voltage current flow across the spark plug gap.

And yes, igniters can and do go bad. Often (but not always) one can tell an igniter is going bad from an erratic tachometer reading, as the tachometer gets its signal from the igniter on Toyota engines.

 

^^ I was trying to keep it simple. Thanks for correction/direction!

Apparently the gap between 2VZ and 3VZ went to cam/crank triggers & the ECM. . . but I sorta breezed threw that. My bad. . .
To date I have not found a 3VZ PDF containing useful info like I have on the SE/MZ family. You have this?

The MZ; those guys use the igniter to feed a coil collapse signal back to the ECM. If no signal (did the spark occur) they kill the signal to the igniter and nobody gets a spark! You get 200 crank rev's before a CEL is triggered!

Lets see what comes of it. . .

 

Thanks guys, I guess if I ever have a erratic Tach idle reading it might possibly be a bad igniter! Right now it's rock solid! Thanks!