Problem:
The ignition system isn't outputting a signal to the ignition coils. Where we would expect to see 12VDC on the coil terminals, there is 0 volts.

Applicable parts:
AEM EMS 30-1040
MSD DIS-4+ HO CDI box (P/N 62153), MSD Blaster SS coils (x4)
T1 Hall Effect Sensor (wired to B11, B15 and using 12VDC+ reference and chasis ground)
FJO Injector Driver box

Background:
The ignition system is set up to fire sequentially. Car ran fine last season using the same hardware and hardware configuration. The one thing we did change was the powertrain wiring. The wiring was redone to separate the chasis wiring from the engine wiring.

The ignition coils were wired to switched ground, as were the injectors.

What we know to date:
1.) The fuel injectors are not outputting during cranking.
2.) The AEM EMS coil drivers are not outputting during cranking. No spark.
3.) STAT SYNC'd = "ON" when cranking
4.) T2PER and Crank Tooth Period outputs integer values while cranking
5.) Air clearance is set to .024"
6.) There is continuity to the coils from the AEM ECU harness. We know this because we can physically ground the coil outputs through the harness and it'll trigger the coils. Same with the #2 fuel injector; there is continuity. We can manually ground the circuit and the injector clips will light up the test light.
7.) The coils are showing as "OFF" when monitoring COIL 1, 2, 3, 5 in the parameters window. But, we can use the test mode to force the EMS to turn "ON" and output on any coil we want and it does ground the circuit and we get voltage out of the correct pin (test light turned on).
8.) When a coil is forced to "ON", the EMS parameter will show it as "ON", but when checking the output at the coil, it doesn't get any voltage. We're thinking that it may not have enough voltage while in test mode and that's why it won't trigger the coil even though we have contiunity and an obvious output from the AEM EMS coil driver.
9.) The ECU/sensor grounds were wired up such that if the factory electrical diagram called for a chasis ground, it got a chasis ground. If it called for a sensor ground through the pins in the ECU, it got a sensor ground.

We've been trying to isolate and understand the issue for 12 hours yesterday, but without much luck in getting a solution.

Questions:
1.) Are the coil outputs on the AEM monitor ideally supposed to be "ON" when the EMS has power?
2.) Does the ignition output use a dedicated ground input other than the ECU grounds at, I think, A23 and whatever the other one is?
3.) Is there a setting that needs to be turned on to get the EMS to output?
4.) Are there any other checks to help isolate the issue? We're still not sure if we have good hardware or not.

 

Have you called the AEM tech line. For the most part, they seem to be helpful.

Only change from last time to this is the wiring? Didn't change any of the ECU settings?

 

No changes to the ECU settings, only the wiring. I've verified the cam/crank inputs as well as the power to both boxes. Somebody else verified the coil outputs were proper and had continuity all the way to the coils.

After the holiday weekend, we're planning on contacting somebody from AEM. We just found the issue yesterday when we tried to start the engine for the first time this season.

At this point, we're just trying to figure out what the expected outputs are so that we can isolate the issue more because I have no idea what the working base line is since this is the first time I've had to work with the AEM EMS to this level of detail.

 

Oh, and forgot to mention that the coils are turned on in the AEM EMS.

Options - Coils
Coil 1, 2, 3, and 5 are checked as active.

 

Did you get this working yet????

What was the problem???

 

Yes. It was the cam trigger wiring. The wiring was backwards in the documentation. We recognized it last year and then forgot again over the course of a year.

 

Glad you got it all worked out.