Intermittent spark problem with DIYPNP - Miata Turbo Forum - Boost cars, acquire cats.

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Old 03-23-2015, 02:02 PM   #1
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Default Intermittent spark problem with DIYPNP

The car is a 1.6L '90 with a DIYPNP installed. Both coils will only fire intermittently on the right side of each coil (right side if you're standing in front facing the engine bay), but will fire consistently on the left side of each coil (Timing light was used to test spark). This causes the car to essentially run on two cylinders most of the time. IOW, cylinders 1 and 3 run perfectly, but 2 and 4 fire roughly half of the time.

I've tried:
- Another set of coils/wires
- Swapping plug wires on each coil
- Different ignitor
- Spark test in tunerstudio and still had intermittent spark on the right sides of each coil. IGN A and IGN B fired their respective coils as expected

With a stock ECU, this doesn't seem to be a problem (although I have not tested with a timing light yet). I just find it weird that a coil that is obviously getting power is only firing like it should on one side. From what I understand, the coil should fire both of the outputs at once. The ECU is obviously sending the correct signal to the coils, as one output on each coil is firing perfectly. I can post a data log and tune tonight. Thanks in advance!
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Old 03-23-2015, 02:12 PM   #2
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If I am not mistaken, it is physically impossible for one side of the coil to hit and not the other, unless of course it's broken. It's called batch fire for a reason, there's only really two signals, two ignitor circuits, and two coils.

Either way, MS can only output two signals to the coils so if they are both working then there is nothing wrong with the diypnp electrically. I bet you have other problems or incorrect spark settings.
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Old 03-23-2015, 04:16 PM   #3
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Quote:
Originally Posted by deezums View Post
If I am not mistaken, it is physically impossible for one side of the coil to hit and not the other, unless of course it's broken.
This is how I understood it. Which makes me wonder how one side of the coil can function properly and the other not. And that two separate sets of coils and wires can have the same problem. I am going to check all the connections in the PNP pertaining to ignition tonight, I'm just not sure how the MS could cause only one side of the coil to fire. Maybe someone can spot an incorrect setting when I upload the tune/datalog as well.
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Old 03-23-2015, 06:52 PM   #4
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Here is the tune and datalog
Attached Files
File Type: msq CurrentTune.msq (109.3 KB, 24 views)
File Type: msl idle2.msl (42.6 KB, 31 views)
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Old 03-23-2015, 10:06 PM   #5
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Your settings match mine.
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Old 03-24-2015, 12:36 AM   #6
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I just went in and resoldered the joints pertaining to ignition that looked suspect along with the grounds. Everything else on the board looks fine. I will be able to test it tomorrow. I am open to ideas in the mean time. This one is stumping me, I hope the problem is not something stupid
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Old 03-25-2015, 02:12 PM   #7
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Problem has been solved. Turns out it was fuel, not spark. My timing light was just not reading well on the problem cylinders.

The main pcb had a (visible) manufacturing flaw and there was no continuity between the inj1 pins on the microsquirt and the inj1 outputs on the main pcb. I simply jumpered the microsquirt inj1 pin directly to the n76 adaptor board and all is well. Frustrating problem to have...
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