Looking for a primary ignition waveform with current limiting
I am looking for a waveform capture that shows full details of the ignition module or PCM going into the current limiting mode before firing (see attached picture for an example).
The waveform should be a manipulatable binary file (e.g., psdata) collected at >100kS/sec with 12+ bit vertical resolution; all voltages measured relative to the battery negative terminal.
- Ch 1 : Primary ignition voltage;
- Ch 2: Primary current;
- Ch 3: Voltage at the coil's power feed;
- Ch 4: Voltage at the corresponding ground terminal (the one that sinks the primary current) of the ignition module or PCM.
- Resistance of the primary winding -- either a picture of the specification in the service information OR measured directly with an ohmmeter (picture of the measurement + picture of displayed resistance when the leads are shorted together).
Please post it as a resource and then reply here with the link. Thank you!
I'll look and see if I can grab you one today, I'll have some time later on most likely.
This is a 1988 Ranger. It's old but it should work. It's clear that they're limiting current. Voltage is referenced to battery ground.
Thanks, Brin! This capture does not include the power feed and ground voltages that I need to complete my calculations, but it has an absolutely "awesome" feature -- oscillations during the current limiting. Qualifies for at least a tip! UPDATE: Tip of 1DNT sent.
Is this something like you are looking for? From a 2007 Honda Odyssey 3.5.
Hi Daryll, unfortunately there is no current limiting happening in this one (the current goes up and up until the firing event)...
Correct, ideally I would have gathered a Toyota 4 wire. Will see if I can get ahold of my neighbor’s Sequoia
Daryll, does the 4-wire you mentioned use the logic level trigger square wave or is actually grounded by the PCM? I need the latter to get the primary ignition voltage with the dwell, firing and burn lines. (in circuit diagram terms, schematics A and B give you the primary ignition waveform, but schematic C does not — it is hidden inside the COP: diag.net/file/f2x1se1t6…
I see. I will keep looking. My other truck has a 2 wire coil with external ICM. 94 Toyota. Will check it
Dmitriy, this should be okay for you. All referenced to the negative terminal/bolt that holds on the battery cable. I'll leave it hooked up and the owner is MIA, so if you want more let me know. This one has some intermittent cross firing in the cap, so readings might have some issues if you are looking for more.
Measured in the coils primary windings.
This is it! Thank you very much, Bill!