[Pezi]

Hey guys...

I have a slightly crazy problem with my EU GA16DE. It has an optical CAS on the camshaft.
The trigger pattern is the same as the Daihatsu+1 decoder (4 large slots + 1 smaller one in front of cylinder 1).
The setup was without any major problems and the car runs really great without sync problems.
But in about 1 out of 10 starts, the engine suddenly starts shaking, running rough and has no power. It almost sounds like it is only running on 3 cylinders, which it is not.
If I turn the engine off and restart it immediately, everything runs fine again.

There are no abnormalities in TunerStudio at the moment when the problem occurs . There are also no sync problems or anything similar.

However, at this point I took my ignition gun in my hand and measured the ignition angle.
At this moment it is not at 10° and completely out of range.
After a good start the ignition is exactly at 10°.

Due to the very limited space in the Micra engine bay, I am unable to determine where the ignition timing is at the moment when the engine runs bad.

What I can say though...
- the error occurs sporadically
- it doesn't matter at what CLT temperature

Is it possible that this is a firmware problem?

Cheers from Germany...

[jonbill]

It does sound like a misreading of the teeth. Do you have a resync every rev option?

[Pezi]

I cannot select the option on Daihatsu+1. The selection window is gray and locked.

[PSIG]

Please post a tooth log, or an oscilloscope image of your tooth pattern.

[Pezi]

I'll try, but I haven't had any problems in the last few days. Or it happens and I don't have my oscilloscope handy at that the moment.

[PSIG]

You can just post an image of the basic tooth pattern, turning or cranking the engine, so we can see all the teeth and gaps on the wheel. Or a tooth log of that. If you have a cheap USB logic analyzer, they also work well for that purpose.

[Pezi]

It took a while before I could get back to my project.
Here is a Tooth-log as csv.

I've tried over the last few days to record everything when the error occurs. But what can I say... if you wait for it, then of course it doesn't happen.
So this logs shows when the engine runs well.

[echomnalez]

Hey. I had the exact same problem with a daihatsu. I ended up changing the wheel for a 36 - 2 wheel. The engine feel instantly changed. It started much better ran better. Also stopped vibrating, I had to lower the fuel in the ve table. It doesn't make sense. But it started working incredibly.
I just can't understand why. Before when it started I felt like cylinders where appearing like while cranking one started then the other and the other. I can't really describe how. Now as soon as I crank the engine the 3 cylinders start right away. Also before when cranking the rpm clock had a delay like 1 sec. Now with the 36 wheel as soon as I crank I have rpm signal.

Also something similar happened to me 1 every 3 to 4 times I cranked it, it would start like retarded and with1 less cylinder working.
Super strange.
This was a customers car. I had to change the wheel because it felt really wrong to deliver the car like this.
I lower a couple points of the ve table where necessary. I retimed the trigger angle with the timing light and delivered it.

I don't really understand why but I started thinking that maybe with that decoder it doesn't use the same advance in every cylinder, I can't back this up, but that's the only thing that I can think of why it would cause this to happen. It would explain why I had to lower the ve table just a couple of points and why it started like a cylinder at a time, and maybe the rpm delay because some kind of extra math that it needs.