I swapped the coil wires going to the stock ECU back to the MS, and I'm no longer getting spark (I did a few days ago when I tried it this way).

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I first tested for spark using a high quality spark tester, which you plug a spark plug wire onto, and hook the tool's clamp to ground, no spark.

Tested it with a brand new coil, no spark.

Tested that the coil was getting +12v on the middle pin, it is.

Tested coil signal wires from the coil harness to the megasquirt, full continuity (no resistance).

Tested for resistance across each of the pins on the coil harness in case there was wire failure, no continuity.

All my connections are properly soldered and heatshrinked.

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On the Megasquirt (v3 board, MSnS v029q2 firmware),

The LED's are blinking normally as when spark should be firing.

I reflashed everything and loaded in my old config, with all the settings set properly as mentioned on the 420a MSnS v3 setup webpage.

My cranking dwell is 8.0 ms.

The board was assembled by RS-Autosport with the 420a decoder mod of course.

I get proper RPM while cranking.

I haven't tried Corbin's tach noise fix yet.

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Anybody have ANY ideas? I'm gonna take out the MS board right now and just stare at it as if I'll see something wrong...

Joel Baldridge, ASE Certified Master Technician, Audi Certified Expert Technician

the Tahc noise should still give you spark and get you running. That is a separate issue.

When you hook the coil to the Factory ECU do you get spark? I assume you do. You can use that to determine the coil is fine and the problem lies in the MS.


Dependign on how Rodney soldered up the VB921, it could have come unsoldered or broke. Open the case up and make sure everything looks ok.

You verified the settings were ok, Test the VB921's to make sure the appropriate pin has ground (#3), output pin (#2) has continuity with the corresponding output wire in the harness, and the input pin (#1)is soldered to the spark output on the PCB.

Terry

Hey Terry,

I opened up the MS and everything was done *perfect* on it, really impressed with Rodney's work. I wasn't getting voltage at the signal pins coming in from the coilpack when I directly powered the ASD circuit from the ASD relay, but I was on the fuel injector outputs.

It turns out I'm having an intermittent connection problem to the coil for the +12v supply. This was the first thing I checked, and I got voltage, but I went to check it again, and nothing. I've been moving a bunch of stuff around, and changing things here and there on the ASD circuit, and in combination with the already brittle stock coil wires (from when I had a EGR system a few years back) I must have finally goofed it up.

Tomorrow I will be running the Megasquirt+injectors+coil on it's own relay, like I should have from the beginning.

'preciate your time.

Joel Baldridge, ASE Certified Master Technician, Audi Certified Expert Technician