Is it normal for the ignition output pin to read 0 V when the ignition switch is ON?

EMU BLACK / CLASSIC
1

With IG ON and the engine not cranking:

  • G8/G16 to ground measures 0 V.

  • Fused +12 V to G8/G16 measures about 12 V with a multimeter.

My concern is whether it is safe to connect the passive ignition coils in this condition.

If there is always about 12 V between the fused +12 V line and the ignition output pins, does that mean current will continuously flow through the coils and possibly burn them out? Or is this normal behavior for low-side ignition outputs when the coils are not connected?

I want to confirm this before plugging in the coils.

3

Connect a coil and measure the current flowing through the circuit. Being a passive coil, it should be fine being connected for a few seconds while you take a measurement.

An alternative (and good for testing) would be to connect a 10W, 10 Ohm resistor and connect that up instead of the coil.

4

What current reading should I look for to confirm the transistor is shorted? At what point does it go from ‘normal phantom voltage/leakage’ to ‘faulty continuous ground’?

5

Using a test light (globe type, not LED) in place of the coil would be a much simpler test.

Test light from Batt 12v to the IGN Output pin and see if it lights.

The test light will be the load in the circuit keeping the ecu safe.

6

I tested G8 with the ignition coil disconnected.

I connected a 2.2 kΩ resistor between fused ignition +12V and G8, then measured G8 with the oscilloscope referenced to engine/system ground.

During cranking, RPM, cam signal, and dwell time are present, but I do not see G8 pulling low.

7

Good test. Interesting result.

Im gonna assume you have the ign outs set up to drive passive right?

Is this CLASSIC or BLACK?

BLACK has built-in circuit protection for cases where incorrect coil type has been selected, CLASSIC does not.

You clearly have a good understanding of circuit testing. What is your reason for doing these tests? Do you suspect you have cooked the board somehow already?

8

It is an EMU Black, and I am using the V2 software.

The engine has previously started and run smoothly with this map, so the basic map/configuration had been working before.

But at some point it stopped working. During diagnosis, I removed the spark plug and checked for spark visually while cranking, but there was no spark.

That is why I am now investigating multiple possible causes, including configuration, wiring, coil, and possible ignition output/driver issues.

9

You dont have to crank the engine, did you try test output ?
If test output working you need to fix something with the triggers…

10

Have you had anu success sorting out the issue yet?