For discussion of Speeduino compatible boards designed / built by other members of the forum and for guidance around making such a board
By sk8
#48147
Vauhtivaunu wrote: Mon Feb 08, 2021 5:31 pm
sk8 wrote: Mon Feb 08, 2021 5:18 pm
That's what I tried the first time but the car ran really weird
Check your coil pinout and ignition wires. Some Bosch coils are for V6 engines that have differend firing order than BMW straight 6 so cylinder numbering in coil nor pins are not suitable for bmw.
https://www.yumpu.com/en/document/read/ ... motorsport
This is the coil I'm using, had pin 4 to 12v, pin 3 to IGN3.2/4, pin 2 to IGN2.1, pin 1 to IGN1.1. On the coil it's wired
COIL -> ENGINE
5/2 -> 1/6
3/6 -> 2/5
1/4 -> 3/4

Will go and test out wiring pin 3 to IGN_3.1 instead of IGN_3.2/4 and post an update if that fixes my issue.
By sk8
#48152
Vauhtivaunu wrote: Mon Feb 08, 2021 6:05 pm
sk8 wrote: Mon Feb 08, 2021 5:59 pm https://www.yumpu.com/en/document/read/ ... motorsport
This is the coil I'm using, had pin 4 to 12v, pin 3 to IGN3.2/4, pin 2 to IGN2.1, pin 1 to IGN1.1. On the coil it's wired
COIL -> ENGINE
5/2 -> 1/6
3/6 -> 2/5
1/4 -> 3/4
That should be correct.
Just tried it out, that did not work unfortunately. Engine would have a loud backfire every 5-10 seconds of cranking. Switched the wires around to
Speeduino -> Coil -> Engine
IGN1.1 -> 5/2 -> 3/4
IGN2.1 -> 3/6 -> 2/5
IGN3.1 -> 1/4 -> 1/6

This made the engine crank over but ran extremely rough. This seems like a dumb question, but does the trigger angle change with wasted spark? I ask because when I used a timing light initially on my engine with the cap/rotor my trigger angle was 50, but I see many other people with m20b25 engine have trigger angle of 84.

EDIT: The issue was my trigger angle. I set it to -84 and verified with the timing light, car cranked right up. I'm really confused why my trigger changed with wasted spark vs using stock cap/rotor. Car was running smooth at 50 degrees with the stock cap/rotor. I checked with the same timing light both times.
By Vauhtivaunu
#48171
sk8 wrote:

EDIT: The issue was my trigger angle. I set it to -84 and verified with the timing light, car cranked right up. I'm really confused why my trigger changed with wasted spark vs using stock cap/rotor. Car was running smooth at 50 degrees with the stock cap/rotor. I checked with the same timing light both times.
That must be something in code. I use 276 degree angle with motronic 60-2 trigger as that is what Speeduino supposed to "see". Remember Speedy want´s trigger AFTER top dead center. Not like most other ECU:s before TDC.
By sk8
#48215
Vauhtivaunu wrote: Tue Feb 09, 2021 9:55 am
sk8 wrote:

EDIT: The issue was my trigger angle. I set it to -84 and verified with the timing light, car cranked right up. I'm really confused why my trigger changed with wasted spark vs using stock cap/rotor. Car was running smooth at 50 degrees with the stock cap/rotor. I checked with the same timing light both times.
That must be something in code. I use 276 degree angle with motronic 60-2 trigger as that is what Speeduino supposed to "see". Remember Speedy want´s trigger AFTER top dead center. Not like most other ECU:s before TDC.
I think 276 is the same thing as -84, they are 360 degrees apart. Not sure if that makes any difference in speeduino.
User avatar
By PSIG
#48225
Agreed to the last 2 posts. The two TAs are simply 360 (1/2 cycle) offset. If using waste-spark, it is irrelevant as the coils fire every cylinder on every crank rotation. However, fuel may be 360°-out if single-squirt or sequential (injection end on exhaust stroke instead of compression stroke).

While paired/semi injectors will run "OK" firing on either cycle, it will run randomly differently with the change each startup, unless set for 2-squirts/cycle (equivalent to waste-spark), or a cycle signal is used. If sequential or timed batch and it's injecting on the wrong stroke, move it with TA to the correct stroke, e.g., 276 - 360 = -84°.
By sk8
#48227
PSIG wrote: Wed Feb 10, 2021 3:44 pm Agreed to the last 2 posts. The two TAs are simply 360 (1/2 cycle) offset. If using waste-spark, it is irrelevant as the coils fire every cylinder on every crank rotation. However, fuel may be 360°-out if single-squirt or sequential (injection end on exhaust stroke instead of compression stroke).

While paired/semi injectors will run "OK" firing on either cycle, it will run randomly differently with the change each startup, unless set for 2-squirts/cycle (equivalent to waste-spark), or a cycle signal is used. If sequential or timed batch and it's injecting on the wrong stroke, move it with TA to the correct stroke, e.g., 276 - 360 = -84°.
Thank you for the explanation. Is there a way to determine which one is correct for my engine -84 or 276? These are my engine constants and trigger settings. Running 60lb injectors and wasted spark.
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User avatar
By PSIG
#48236
The reference for correct engine cycle (stroke) would be the cam. Note where the cam signal is relative to #1 TDC on the compression stroke. From here you can use a 'scope or logic analyzer to see the injector pulse relationship to cam angle. If you have a signal conditioner with diagnostic LEDs, you can even use a video of the Speeduino LEDs (viewed slow or frame-by-frame) to determine if the injector pulses end near the relative #1TDC position, or 360° offset.

An alternative if you can see your cam position — test your timing light to check triggering on #1 injector. More often they trigger on the ground wire, but try each, or try clamping the injector body. Some lights have a direct-trigger input for a 12V signal also. 8-) If it triggers, set the engine to #1 compression TDC, and mark the cam pulley and housing. Most OHC engines already have a mark there. Run it. While it will be blurry, the pulley mark should be visible near the housing mark, or 180° away if wrong.
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