[Jason hall]

Hi,

Anyone decoded this on a dropbear ?
12 on crank continuous
2 and 1 on cam

[Jason hall]

Gave up , broke two teeth off and back to a single reset .

The single tooth is 90-120deg before tdc no1 . ( hard to measure due to vr)

Can I confirm the correct ign angle to use for this ? Let’s say it’s 120deg btdc no1 for eg

I’m just spinning it over with no plugs trying to get it to fire off a timing light at tdc with ign locked at 0/10 and 20 deg bred before I go any further .

[jonbill]

Calculating the trigger angle is described here for your dual wheel setup https://wiki.speeduino.com/en/decoders/Dual_Wheel
I think the only bit that could be more explicit would be to add "passes under the sensor" to the end of the "timing setting" paragraph.

[digmorepaka]

Be careful which VR conditioner you use, this would probably want the DSC discrete or NCV1124. The MAX conditioner will likely time out on that 1 tooth cam with it's random pulse rejection below ~1700 rpm.

[Jason hall]

Be careful which VR conditioner you use, this would probably want the DSC discrete or NCV1124. The MAX conditioner will likely time out on that 1 tooth cam with it's random pulse rejection below ~1700 rpm.

It’s a dropbear V2 with built in conditioner . I have the switches set to VR and that’s it . I have tried each setting for the filtering .

Calculating the trigger angle is described here for your dual wheel setup https://wiki.speeduino.com/en/decoders/Dual_Wheel
I think the only bit that could be more explicit would be to add "passes under the sensor" to the end of the "timing setting" paragraph.

Yeah I see that .

If my tooth is say before tdc by 90deg do they class that as -90deg since it says the measurement is the tooth “atdc” measurement +/- 360deg ?

[Jason hall]

Update -

I can finally get spark and cranking with a timing light but it’s all over the place , every time it cranks it’s in a new position on the timing light .

With a scope it’s got the patterns on each wire to the ecu so it’s getting a crank and reset signal .

I have it set to dual wheel, rising , tried all filter settings , tried reset every time yes and no .

I’m missing something I’m just not sure what . I have tried varying trigger angle settings and it makes no difference , every crank restart is firing at new angles .

What am I doing wrong here ?

[Jason hall]

Calculating the trigger angle is described here for your dual wheel setup https://wiki.speeduino.com/en/decoders/Dual_Wheel
I think the only bit that could be more explicit would be to add "passes under the sensor" to the end of the "timing setting" paragraph.

Also with this :
Timing Setting
The trigger angle can be found by placing the engine at TDC, then calculating how far it must be rotated until the first primary tooth after the secondary pulse.

Now does this include rotating backwards ?

I’m 3.5 teeth to reset approx then the 4th tooth backwards is the first after the reset . So that’s in theory -120deg.

With this and every other setting the timing is all over the place on every restart with a new timing location on the timing light . It stays stable while cranking but as soon as its cycled its a new timing position .

I have it set to do two cycles before outputting so it can find the reset signal but it’s still the same .

[PSIG]

OK, you seem to already 'get' most of it, but let's work up to finding TDC for Speeduino, so we are on the 'same page'. This is how my brain sees it, so I will use some of my previous posts to describe it. Review this, then review the linked page in it to here.

If that is making sense, you can see that positive numbers are the crank rotating past TDC to find Tooth1, and that negative numbers are the same position, but on a different stroke or cycle. This makes no difference to crank-only setups, where wasted-spark and multiple injections-per-cycle are used, as every crank rotation is seeing spark and fuel at the same points across all cylinders. No worries.

However, and to extend the effect of + and – Trigger Angle, for (example) full sequential with a cycle ("cam") signal, using a positive or negative number will change the beginning of the 4-stroke cycle to the other crank rev of that cycle. This actually changes Speeduino's understanding of the position of TDC Cyl1 compression stroke to a different cylinder, or Cyl1 on a different stroke. This begins the cycle to make injections and sparks in proper order in the 2-rev 4-stroke cycle. I hope that makes sense, and partly when it would make a difference.

[Jason hall]

OK, you seem to already 'get' most of it, but let's work up to finding TDC for Speeduino, so we are on the 'same page'. This is how my brain sees it, so I will use some of my previous posts to describe it. Review this, then review the linked page in it to here.

If that is making sense, you can see that positive numbers are the crank rotating past TDC to find Tooth1, and that negative numbers are the same position, but on a different stroke or cycle. This makes no difference to crank-only setups, where wasted-spark and multiple injections-per-cycle are used, as every crank rotation is seeing spark and fuel at the same points across all cylinders. No worries.

However, and to extend the effect of + and – Trigger Angle, for (example) full sequential with a cycle ("cam") signal, using a positive or negative number will change the beginning of the 4-stroke cycle to the other crank rev of that cycle. This actually changes Speeduino's understanding of the position of TDC Cyl1 compression stroke to a different cylinder, or Cyl1 on a different stroke. This begins the cycle to make injections and sparks in proper order in the 2-rev 4-stroke cycle. I hope that makes sense, and partly when it would make a difference.

Yeah , so I setup my cam reset 3.5 crank teeth before no1 tdc. So 3.5 x 30 =105 deg btdc

So do I not use just -105deg for a start as the trigger angle then fine tune it ?

Cos as it stands now it’s a different advance fired every time I crank it with that setting .

[LPG2CV]

Just a randon thought.

Are you getting electrical inference that is randomly firing the cam signal?

I've not read back through the topic. How is the cam signal shielded? Where is it grounded?