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I am using Speeduino to fuel inject a type 1 VW engine to be installed on an experimental aircraft. Since I do not intend to install a starter (hand propping), it is a requirement that the spark and injection cycles start after the first missing tooth on a 36-1 wheel.

You will notice in the attached logic analyser output that I have managed to alter the decoder to provide an ignition event following the first missing tooth.

My concern is obtaining the ability to alter the code to provide injection events during the revolution following the first lost tooth.

The logic analyser output shows the injectors wide open until the second revolution .

I have investigated the code far enough to determine that the injectors are ordered closed in init.ino.

Control of the fuel pump during the priming sequence may have some connection to this condition?

Any suggestions or assistance to help with these issues is appreciated.
screenshot.png (78.08 KiB) Viewed 755 times
screenshot.png (78.08 KiB) Viewed 755 times
MA - where are you reading for the analyzer? If reading the components, the signal goes high for IGN coil driver dwell, but the injectors read +V until grounded to inject. Anyway, where you're reading the signals makes a very big difference.

In response - the logic trace is the signals at the speeduino board outputs.

I am using the release of 11/xx/2019.
No code was changed to affect the injectors except to set sync after the first missed tooth.
My setting for priming was 6. I will test at 0.

Further information for those interested. I am not planning to use the fuel pump control signal. An additional hardware module may be added to provide a priming pulse to the injectors prior to cranking.
I've just spun your tune up with the current firmware and couldn't see any issues at all. Everything stops/starts exactly as I'd expect it to, but I'd be surprised if there's been anything between the 201911 and 20203 firmwares that changed here.
MichaelAxelrad wrote:In response - the logic trace is the signals at the speeduino board outputs.
Remember that the Speeduino board injector outputs go low when active (Which is the opposite of the arduino outputs as it's an inverting driver). If you are actually measuring on the injector driver output, seeing it go high when inactive is correct.
Thank you for your analysis. After restudying the schematic, I recognized that since I hadn't connected a 12 volt supply the out put was floating.

I have used a Microsquirt in a prior project. Your efforts have been superior on all fronts. My best wishes for your continued success.

Attached is the corrected output.
correct out.png
correct out.png (77.94 KiB) Viewed 576 times

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