Custom electronic fuel injection and ignition

[dlbass93]

I finally got up the nerve to try cutting aluminum on my Shapeoko, and the result was excellent, especially considering how sketchy my workholding was. I super glued the aluminum stock to a 3D printed fixture that was only clamped to the table with nylon toe clamps... It worked though! 9/16-18 thread in the top accepts an adapter to 6AN, I'm still playing with the hose routing, not really happy with all those fittings up on top yet. Will probably just make a traditional fuel rail that holds both injectors in the final design.

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Tach input from coil negative is not working as I had hoped, so the ignition retrofit is now part of phase one. Crank angle sensor bracket, trigger wheel mockup, and temporary coil hangers are designed and printed. Send Cut Send is laser cutting the real trigger wheel from 1/4" steel, and it should be here in a few days. I got some old GM truck coils, and a Toyota crank sensor from a junkyard for development.

It is getting close...

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[dlbass93]

It lives!!!

There's still a lot of work to do, but it ran under its own power this afternoon. Before I blew anything up, I called that good and drank some beer.

The two part trigger wheel turned out really well, and doesn't look too out of place on the engine.

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The wasted-spark individual logic coil ignition makes such a beautiful, bright spark in my little tester. It must be a dozen times more power than the old worn out distributor, even on these junkyard Ford wires. Since the Microsquirt can only run four ignition circuits, I have wired it so that two coils fire together on three circuits. One and six, two and five, three and four. It seems to be correct.

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To get it to start, I have to artificially enrichen the cranking fuel by pouring a dash down the throat, but once it starts it runs on its own. Gotta learn how to tune that enrichment automatically in the computer.

Other things to finish up:
Build better crank angle sensor bracket to clear the fan (tight clearances up there)
Install fuel tank
Build last piece of throttle linkage
Build second injector hat and fuel lines
Build air cleaner interface
Tune!

[Johnny Roadkill]

Congratulations - stoked to hear you've got to that point so rapidly, the custom parts look great and I'm looking forward to hearing how it performs once the tune is dialled in !

That hot spark should make a nice difference too - I have always wondered why OEM ignitions don't maximise the benefits of hotter sparks...plug life ?

Cheers,
D

[dlbass93]

Still making progress! This weekend I got it starting and staying running without any help. It looks like as it warms up and the enrichment drops off, it starts getting unhappy, so I've got some tuning to do.

So far as I can tell, everything is working. I guess I'll start making some real parts to replace these 3D printed plastic ones. The plastic throttle plate is only about .07" thick, and undergoes some pretty significant deflection when trying to get the engine off idle. The throttle shaft and arm also aren't as stiff as I'd like. In the last part of the video of the ECU dashboard, you can see it start to lose tach input and stutter. I think that is my plastic crank angle sensor bracket allowing too move movement in the sensor. Metal parts here we come...

Here's a little taste of how she sounds this morning. This is basically a stock tune that the software automatically generated. Now I have to learn to dial it in. There is a lot of background noise of the half-attached bodywork rattling around, and the water pump pully squealing, but overall, I think the engine sounds pretty darn good. My portable AFR meter is saying it is very lean. That makes me really want to jut put an O2 sensor on it and let the automatic tune do its magic but that also feels like cheating.

https://photos.app.goo.gl/dLGhw4fSn2N6vGWo7

[faux40]

Congrats! That is awesome!

I say go with the O2 sensor - cheating or not!

John

Still making progress! This weekend I got it starting and staying running without any help. It looks like as it warms up and the enrichment drops off, it starts getting unhappy, so I've got some tuning to do.

So far as I can tell, everything is working. I guess I'll start making some real parts to replace these 3D printed plastic ones. The plastic throttle plate is only about .07" thick, and undergoes some pretty significant deflection when trying to get the engine off idle. The throttle shaft and arm also aren't as stiff as I'd like. In the last part of the video of the ECU dashboard, you can see it start to lose tach input and stutter. I think that is my plastic crank angle sensor bracket allowing too move movement in the sensor. Metal parts here we come...

Here's a little taste of how she sounds this morning. This is basically a stock tune that the software automatically generated. Now I have to learn to dial it in. There is a lot of background noise of the half-attached bodywork rattling around, and the water pump pully squealing, but overall, I think the engine sounds pretty darn good. My portable AFR meter is saying it is very lean. That makes me really want to jut put an O2 sensor on it and let the automatic tune do its magic but that also feels like cheating.

https://photos.app.goo.gl/dLGhw4fSn2N6vGWo7

[Johnny Roadkill]

Cheating ? Nah, once you're using a microcontroller to meter fuel instead of jets you're already playing by a different set of rules - use the tech !

...and take a bow - nice work

Cheers,
D

[dlbass93]

Alright guys, you convinced me. Going all-in with the wideband O2 sensor as well.

After looking deeper into the documentation, it turns out my Innovate LM-2 portable wideband O2 tool can be wired into the Microsquirt, but my starter kit doesn't have the appropriate pigtail. That should be an easy fix.

[L60Boerne]

I salute you. You are either a retired assembly line worker from a John Deer factory or NASA team leader with several moon shots under your belt. Either way, fuel injection is a huge step up. My mechanics, not me, converted a small V6 several years ago on one of my hunting rigs that I thought would be used for aggressive mounting trails but my boneheads did not leave enough room in the engine bay for an adequate radiator so I can only drive it on cold winter days.

Still, throttle body injection works and really works on acute angles vs gravity....but you already know more than I can even imagine.

Patrolling in snow at 9,000 ft in 4 days,
L60Boerne

[dlbass93]

I wish I was a NASA team leader. I do know some folks who work at NASA in Huntsville, and I can't even pretend like I understand that stuff! I'm a bored-at-work software engineer by day, and an unreasonably unafraid disassembler of everything when I get home.

Lambda sensor is installed and temporarily wired in. (Read hot-melt glued wires) Even though the engine is running so insanely rich that fuel is combusting in the muffler and my shop quickly fills with a fog of healthy for breathing exhaust, the sensor is saying the AFR is over 22:1. I'm hoping it is a voltage issue making the sensor read so horribly wrong.

Slow going, but it's coming along.

Another potential issue I haven't wrapped my head around is the wasted-spark coil-on-plug ignition. I have a digital timing light that has a tachometer function. I can get a steady tach reading when the inductive clamp is on spark plug wires 1, 2, 3, or 6. But when the clamp is on 4 or 5 the reading is brief if at all. I've moved coils and wires with no change. Coils 3 and 4 are wired together to fire together, so I checked that each wire in the coil connectors for 3 and 4 had continuity, continuity on the ground end-to-end, and continuity on the power end-to-end; so I think my wiring is ok. But, when I put the inline spark tester light on, you'd have no idea anything is amiss; it fires beautifully without a hitch. Anyone got ideas about this? Does it even mean anything that my inductive clamp is playing tricks?

I'm going through all this in search for ultimate engine smoothness. It is not running smoothly now, but it never ran smoothly before. I haven't picked up a compression tester yet, but I never thought it wasn't firing on all cylinders before.

[dlbass93]

I figured out that my extremely lean condition is not a sign of anything wrong with my electronics work, but that the engine is not having complete combustion in most of the cylinders, so there is an abundance of unburnt oxygen in the exhaust (where you want all the oxygen to be used up to make zoom zoom).

Some poking around this evening showed me that the engine is really only running on cylinders 4 and 6 (maybe 5 is helping a little). Very strong spark is present at all cylinders. This was verified with the timing light (4 and 5 still don't give a reliable tach signal, but all others do), inline spark tester light, and finally by unplugging each plug wire one by one with the engine running to see the wire arc to the plug. I can unplug all but cylinder 4 and the engine will chug along, adding 6 helps it chug faster, adding in five maybe helps it be steadier, but 1-3 have zero affect on it running. It will not start without cylinder 4 connected.

All cylinders are getting at least some fuel. The plugs get wet after lots of running (can I call it that?), and 4 and 6 get some serious rich black smut after only a minute.

I think I must be injecting fuel at just the wrong times, but I've got to figure out a way to prove it so I can fix it.

Lots more learning to do...