I was watching the video where Paul is testing the 4 wire coil (Toyota/Lexus). The amp clamp was around the ground wire and the DMM was backprobed to the IGT (I think). He did the test using a Pico scope, but I was wondering for those of us who don't have a scope, what should the readings be on the current and voltage or does it depend?
Thanks.
MrMike
"The object of war is not to die for your country but to make the other bastard die for his"
The dwell period when the coil primary is powered up only last about 3ms and the spark only last about 2 to 3.5 ms from start to finish. No meter can capture that although there used to be custom electronic tools for measuring kv
ll you can do apart from checking the B+ supply is go old school and estimate the secondary voltage using an air gap being careful not to make the gap too wide or the high kv needed to jump the gap will damage the coil. Generally if the spark can jump the width of a finger in air it is strong enough.
" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)
I was thinking after I posted that, the speed of the time would be too fast to measure. I guess as long as I can see spark, all is good. So, whats the difference in the wiring between the 3 or 4 wire coils besides one having one more/less wire.
Thank you Sir
"The object of war is not to die for your country but to make the other bastard die for his"
3 wire coils feature a wire for power supply to the coil, another one for ground to the promary and the third carrying the control signal from the ecm to the ignition module built within the coil itself. On 4 wire coils 3 of them will have the same functionality, power&ground for the primary plus the trigger signal on the third wire. The 4th wire may carry an ignition confirmation signal back to the ecm from the ignition module as the IGF signal with Toyota or the CSI signal on GM compression sense systems . Other manufacturers do use this fourth wire as dedicated ground for the trigger signal, eg VW/Audi.
An expert is someone who knows each time more on each time less, until he finally knows absolutely everything about absolutely nothing.
Essentially these days we have three main types of coil or coil packs primary circuit.
(1) Two wire --- just ign+ and controlled ground via ECU. The secondary can be plug top or wasted spark shared between two cylinders as on a Freelander I On older systems there may be a an amplifier (igniter) module between the coil and and the ecu.
(2) Three wire which have the transistor amplifier igniter module built into the coil pack --- three wires ign+ , main ground and a control wire going straight to the ECU. Essentially the igniter module can be thought of as a relay built into the ECU.
(3) On four wire systems where the fourth wire is a confirmation signal the primary reason it is to protect the catalyst from damage.
" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)
Andy-
Thanks for the explanation. Im taking a lot of notes to add to my reference binder. I think by the time I get done, I could probably write a book about it. I wish I would of known about this Scanner Danner stuff a few years back
"The object of war is not to die for your country but to make the other bastard die for his"
