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Any strange behaviour, crashing issues etc, post them here! Problems compiling the firmware should go in the General support section rather than here
By Gshorten
I have a 0.4.4c board which has been working well. 4cyl engine, wasted spark & semi sequential injection , just a crank signal. I started having some intermittent epsiodes where I would lose spark. Stopping the engine and restarting after a minute fixed it, but then it failed completely. I've checked the crank signal on an oscilliscope, it is good, and replaced the vr conditioner, and now have it back on a jimstim - the injectors are firing properly (and the LEDs show this), but the ignition channel LEDs are all lit solid, and there is no output on any of the ignition channels. My conclusion is that the ignition outputs have failed for some reason. Has anyone else seen this? Am I missing something?

- I've confirmed I have a good crank signal, and I am getting rpm & injector ouput from the speeduino. All other inputs/outputs are working.
- I'm using a jimstim on the bench, everything working, except:
-ignition LEDs are lit solid, and there is no signal on the ignition outputs

BTW makes no difference if I set the ignition output for 5v or 12v - no signal either way
By Gshorten
I swapped out the mega for a brand new one, no change.
Using a smart coil from a 2000 Jetta, it's a wasted spark logic coil. I also replaced it with a brand new one, no difference.
I've also carefully inspected the board for broken traces, unsoldered components, etc... but of course the 0.4.4c board is all surface mount. Nothing obviously amiss.

Again, this was all working great for ~ 500k or so.

https://www.amazon.ca/Bosch-0986221048- ... 0608&psc=1

I am thinking the ignition drive transistors on the speeduino board have failed. too much current? do I need to add something (resistors) to limit current ? (with a new board :-( ). However I would think that they would fail suddenly, not gradually? and not be intermittent first?

This is weird too... I just noticed on the bench that with the arduino + speeduino plugged into usb (so just 5v, no 12v connected to speeduino) the ignition channel LEDs all light up (dimly)...like there is a short to ground through the igntion channels.
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By Chris Wolfson
You have two and a half options, a. get a new Speeduino or b. spend a lot of time with the old one solving a puzzle.
In your position I would take c. get a new one and use it to compare levels on the board with an oscilloscope or voltmeter. This is the fastes way to get to the cause of the problem and keep your car going.
SMD boards can have all kind of issues, they are not a" no fail" product.
Repairing needs a few basic tools, at least special solder, a very small soldering iron and some kind of magnification device.
Some would not even start to repair without an oscilloscope.
SMD boards can have just as many causes for faults as "normal", through hole designs. just anything made smaller...
Set up on the bench and add some leds to the ignition outputs, or buy a cheap logic analyser.

Are the coils smart coils, or do you have ignitors in there somewhere. 12/5v selected? If Hall effect sensor, do you have pull up in place?

its not impossible to create an issue whilst fixing another, so assume nothing and start from basics.

Its as much a process of elimination as it is of pinpointing the issue. Narrow it down with as many tests as you can think of.
By Gshorten
Thanks guys for the input. I have an oscilliscope, Jimstim simulator, so I've checked everything out from beginning to end, both in car and on the bench. I know I am getting good crank signal, and the logger shows that too. Just no output at all on the igntion outputs. Not my first ECU project. I agree, I think it's the speeduino board. I've ordered a new one. What I am wondering now, and I will research this..is it possible for an igntion ( logic) coil to draw more current than the speeduino ignition circuit can deliver? What caused the speeduino board to fail? I would assume there would be protection for this on the speeduino board.... I this is a potential then perhaps I have to put current limiting resistors on the outputs, or something else.

I am not going to try to replace components on an SMD board. I have built many electronics projects, trying to replace components on smd boards is usually a waste of time. Easier just to buy a new one :-)

Thanks again, I'll post an update when I get the new board.
By theonewithin
There is no need to limit the current for the IGN outputs.

Have you actually checked that the Arduino is commanding the outputs on?

It could be a firmware corruption/tune issue that you are missing.

Check the actual output at the Arduino to see if it changes state.

Also see if you can supply power to the IGN transistor to see if they will turn on that way.
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Gshorten wrote:
Fri Jan 15, 2021 6:52 pm
… -ignition LEDs are lit solid, and there is no signal on the ignition outputs

BTW makes no difference if I set the ignition output for 5v or 12v - no signal either way
All four lit? You are only using two channels, correct? As you could not burn-out two channels you are not using, I would suspect something other than the TC4424s. That said, I would also 'scope the inputs on the TC4424s for signal. If no joy, try back at the Mega pin for it. If necessary, pull the TC4424s in order to verify a short. Replace the one you have been using with the other unused TC4424 (verify correct orientation) and test again.

Using that Bosch coil type (106B style) on a 0.4.4C will require 5V signal only. Selecting 12V can overheat the chip, and possibly the modular coil driver in the coil pack. As already stated, do not add resistance on the output, as 10-ohms on the board (check that ;)) is correctly in-range.
By Gshorten
Thanks! I was using 5v output to the coil. Yes, was only using ign 1 &2, so odd that all 4 are lit.... in the car and on the bench. I'm going to do the checks you suggested. I agree... if all 4 are lit then must be something else other than the TC4424.

Great, I might buy one now

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