Haltech 750 DROPPING SIGNAL RANDOMLY

Hey guys, I have a Honda J35 swapped into a Miata. I have a prebuilt harness that I THINK is giving me issues. Here's my problem:

The car sputters but doesn't run. It has inconsistent spark. In the datalogs I see that randomly its RPM value is dropping to 0 and subsequently cutting any ignition/injection. Attached is a datalog of cranking the car.

A few findings:

Top to bottom graphs are, 1) Filtered RPM, 2) Battery Voltage, 3) Trigger tooth count, 4) Engine State

Note the dropping out RPM and engine state, but the battery voltage is still strong. The Trigger tooth count also drops down but as we see in the next pic the VR sensor waveform looks good

Top to bottom graphs: 1) RPM, 2) Trigger input state, 3) Home input state, 4) Engine state.

The RPM and engine state drop out and it throws "home tooth count error" but the waveform is consistent for both sensors.

Any ideas??? I've probably spent 40 collective hours on this since switching to Haltech... I'm pretty burnt out.

Thanks

I would say your running problems are related to battery voltage. Perhaps the dwell settings don't properly compensate for reduced voltage. As you note that after the alternator starts working, and the battery voltage comes up, then it dies. Perhaps your injector dead times are incorrect and the change in voltage is causing a real change in pulse width, with it shouldn't. Log injector pulse width, Lambda / AFR and for more clues when it dies.

If this car has never run, try opening the throttle, and giving it some more fuel. And consider getting a new battery, or adding a fully charged jumper battery.

I think your trigger issues are symptoms, not the cause.

Hard to be confident, but if I understand it correctly, when you're cranking it (voltage drop) it coughs and splutters, and when you release the cranking the engine stops?

To me, it looks like there's a wiring error and the ignition and/or injectors aren't receiving the power/ground required in the "engine run" ignition position but, when being cranked they are being powered/grounded. My money would be on the power side.

I'd start by reviewing the wiring, starting at the ignition key, and ensuring voltages and grounds are as they should be. A shortcut may help, if you jumper cable the non-ECU sides of the earths, or power, as appropriate.

Pre-built harnesses are normally sound, but errors do happen, pins do get pushed back, vehicle configurations do change.