TOYOTA Celica GT4 trigger

[SamSpade]

Very informative traces. I am assuming the purple Ch3 and green Ch4 ignition traces were done with the scope probes GND on +12V and the probe tips on the coil primaries (pins 1 and 3 of the Bosch 2x2 coil).

Seems like your dwell is now at 10 ms, as shown by the troughs of Ch3 and Ch4. Also, it is strange that the other coil is building up voltage (down ramp of trace) while the other coil is on the dwell period. I'm not familiar with the characteristics of Bosch 2x2 coil but that is strange behavior to me. Cross inductance, or failed insulation?

[Wayne]

No, the ground pins from the oszi is on ground.

Yes, the dwell time varies allways,
in my setting i have the value 3ms at 14V.

Now i am in the labor again with the drilling machine,
and instead of the coil i connect two relais.
Same behavior, plus ??misfire??.

When i change the ingition outputs to other, which are not connected,
then i have no ??misfire??.

[rob@vems.co.uk]

Theres often an issue with misfire showing - ignore it for the time being, its the trigger error you
Can you identify which are the three running cylinders?  You should test each cylinder with a timing light and ensure that the pairs of cylinders are correctly firing at TDC and BDC.
Running on 3 cylinders could be down to injectors as well as ignition.

You trace looks fairly solid from what I can see - I am a bit concerned with the dips in the cam trigger - the LM1815 chip senses voltage crossing zero, that might be a source of mis-triggering. 

Its also worth taking a look at:
http://www.vems.hu/wiki/index.php?page=InputTrigger/TriggerLog

I have also passed this thread to the dev team, one of whom said:
"reference tooth table" (h1) values 22,16,10,4 look strange. They could (and should) work, but standard practice is to set 18,12,6,0 (or rather 0,18,12,6 for quicker startup), and trigger_tooth=04

[rob@vems.co.uk]

More comments:

"VR campulse is ALWAYS problematic. That with the dips seems to require strong pullup (10k could be tried, but resistance and DC bias measurements needed). A thematical page would ne nice."

"look at the 30+% coil supply voltage drop when the OTHER coil dwells. Clearly the coil supply should be checked, possibly redone"

[Wayne]

Good morning,
thanks for the hints,
what for me is confused too, is the dwell time or the
ignition coil, in Megatune i set them to 3.3ms, but in the scope i see ~10ms.

The dip on the cam trigger is the "little mountain" 180 degrees apart of the trigger tooth.
Is it better, when i remove them with a grinder ?

I disassambled the unit and measure the outputs of the two LM1815,
and there are no problems with the dip, but my drilling machine turns only 3000rpm.

[rob@vems.co.uk]

I think you're going to be having issues with a ground down sensor too.

The suggestion for a pull-up is to ensure that the bias voltage is high enough that the dip never crosses zero.  The voltage from the main tooth is large enough to pull a fairly significant bias voltage below zero and therefore trigger the LM1815.

Best to worry about getting the crank signal clean and reliable and to check the power connection (2mm dia core) to the coils, before getting concerned about the dwell time, dwell is ramped due to voltage and a number of other issues.

[Wayne]

Another scope

make with drilling machine,
light blue is cam sync (with 10k pullup)
blue is cam sync after lm1815 straight to µP
purple and green ignition coils (relais)

h1 table 18,12,6,0

ignition looks good, but in depend of the dwell time, the ignition point varies all the time.
When you meter the scope trace, you can see that the ignition events are not 180 degrees apart.
(sometimes yes, sometimes no)

[rob@vems.co.uk]

Yep - that's not an even spacing on the ignition events.

Lets nail the blue trace first - how much above 0v does the small dip drop to?
If its well clear of 0v we can stop looking at it and start concentrating on the 24 tooth trigger.

Can you scope the 24 tooth trigger now with its lm1815 trace and the relay coils?

We can then check that the thing is triggering off the correct tooth and if there are any anomalies in that signal.

[Wayne]

Here are the scope files,
for better reading i measured purple and green on the
gate of the ITGB's.
20 degrees spark advanced.

[rob@vems.co.uk]

Is that quantization thats causing the thicker light blue lines?
I cant see clearly but they dont look even.
Which would result in an uneven trigger and erratic timing.

You would do well to capture the 24 tooth VR signal along with the output from its LM1815
Then you should be able to see what is causing the uneven spacing.

[Wayne]

No this what you tell quantization what you mean, is only the oszi resolution.
The light blue pulses are exact 24 pulses between one trigger, with exact 100µs.
Measured after LM1815, straight to µP.

But if you want, then i make a new picture with better resolution, but then you can't see
one engine cycle.

[rob@vems.co.uk]

We're not going to be able to see the 24 tooth trace with the right clarity here, so you need to be able to look at the traces and see if you can see where the LM1815 trigger occurs out of sync and if theres a corresponding signal on the VR input.

[Wayne]

The 24 tooth trigger is not going out of sync.

The pulse frome the LM1815 comes allways at zero crossing of the vr sensor.
Allways 24 in one cam pulse.

For me the dwell time is the problem.
At the last post, i set them to 1ms and 0 at 6V,
but on the oszi the pulse is 4ms and variables.
The beginning of the ignition pulse is allways perfect 180 degrees, but the variable
dwell makes the ignition inacurate.

is it possible that this is better with another firmware.
Now i have 1.1.18

[rob@vems.co.uk]

1.1.18 is running on many cars for a number of years, and we've not seen this problem on them.
The majority of these cars are Nissans running external amplifiers - and therefore inverted outputs, so make sure that you're not running inverted.
I have seen ignition advance change with engine speed with the ignition outputs inverted, but never seen variance between spark events.

I'll make sure that the dev team get to see your last couple of posts.

[Wayne]

Is is possible to erase the internal memory of the µP ?
I want to set the unit completly to zero.

Load the firmware 1.1.18 new and make the configs from the start.