# MS2 - Extra with 60-2 wheel : sync loss #17 ?



## ijcameron (May 17, 2001)

The engine is an ABA with 60/2 tooth wheel. I'm using the ABA distributor for second RPM / TDC input.

I logged the tooth count when it was cranking, it's counting the correct # of teeth every time (60 teeth, then a gap, then 60 teeth etc) and it's also logging the cam signal every second wheel event, which is correct.










The datalog shows a pretty clear sync loss count - every revolution of the engine it is losing sync, yet it's not dropping teeth counts ( i counted them manually)?

Oh yeah, the "Lost Sync Reason" is #17, which means " second trigger not found when expected". Makes me think it's either (1) a software setting or (2) the Hall sensor on the cam (dizzy, actually) is not at TDC.











These are my ignition settings, if that's helpful:
MS2-EXTRA V3.2.1
TUNERSTUDIO V1.20
Ignition Settings.
Spark mode: toothed wheel
Skip Pulses: 3
Ignition Input capture: Rising Edge
Spark Output: Going High (inverted)

Trigger wheel arrangement: dual wheel with missing tooth
Trigger wheel teeth: 60
Missing teeth: 2
Tooth #1 Angle : 78 degrees
Wheel Speed: Crank Wheel
Second trigger active on : Rising Edge


Ideas? It's bumming me out - if I can't figure it out post-haste, I'll prob. just revert to using a distributor for RPM.


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## need_a_VR6 (May 19, 1999)

If you turn off the cam sensor does it read rpm? What does just a trigger log look like? It should ve 58 short times and one long, not 60. It might be able to decode due to the cam sensor but should be able to sync on crank only also unless you are seq/cop.

Also cam should be before the missing, try inverting the cam input capture in software or hardware.


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## ijcameron (May 17, 2001)

Thanks Paul, sorry for the delay in replying - my shop is 30 minutes from the house and between kids, work and everything else some weeks it's hard to get there 

I had a goal of running COP, hence the cam input. I turned off the cam input and tried to run MS on just the 60-2 crank trigger wheel - it really wanted to start, but the fuel pump was still cycling rapidly on/off - here's a typical section of the log:










-looks like it's "spiking" every couple of crank revolutions - any way to tune that out? I have the pots turned all the way counterclockwise and there's a small capacitor on the sensor wire per the Prof's suggestion.

Here's the composite log, if it helps:










Thanks,
Iain


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## ijcameron (May 17, 2001)

Also, do these settings look correct? 



> MS2-EXTRA V3.2.1
> TUNERSTUDIO V1.20
> Ignition Settings.
> Spark mode: toothed wheel
> ...


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## need_a_VR6 (May 19, 1999)

What cam wheel are you using? Have you tried changing the cam from rising to falling edge?

The crank log looks good. The spikes in between the missings are just from a small battery and a cold motor.


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## ijcameron (May 17, 2001)

need_a_VR6 said:


> What cam wheel are you using? Have you tried changing the cam from rising to falling edge?
> 
> The crank log looks good. The spikes in between the missings are just from a small battery and a cold motor.


Thanks Paul - I went back and changed the config. file so that MS was seeing only the primary trigger input (from the 60/2 wheel) - same behavior and same log, even with the secondary trigger eliminated. 

Thanks for the advice on the spikes - interesting that they only occur every other revolution of the crank, as if it was caused by the cam wheel. I need to physically remove the wiring connector from the secondary trigger and see if that makes any difference.

The "cam wheel" is actually the one windowed ABA distributor. I did try changing the cam from rising to falling edge with no improvement.

I know it will run on a 4 windowed dizzy, I just hate to admit defeat on this one


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## need_a_VR6 (May 19, 1999)

The spikes are each tdc twice per missing tooth = 2 per rev. 

Disconnecting the cam sensor will at least tell you if the signal in the comp log is noise or not.

Also, what circuit are you using for cam? Spare pin to opto w pullup to js10?


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## ijcameron (May 17, 2001)

need_a_VR6 said:


> Also, what circuit are you using for cam? Spare pin to opto w pullup to js10?


The cam circuit (from the Hall sensor on the distributor) is:

a. SPR3 (outputs to DB37 pin #5) to OPTO IN
b. OPTO OUT to JS10
c. 1K PULL-UP from the 5V in the proto area to OPTO IN
d. Added XG1 / XG2 jumper


Does that look right?


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## Prof315 (Jan 5, 2009)

You want a 10K ohm RESISTOR on the VR+ not a capacitor.


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## need_a_VR6 (May 19, 1999)

Oh my, and the 10k is only needed on the 3.57. I'd remove the cap and try again. 

The cam input mods seem fine.


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## ijcameron (May 17, 2001)

Thanks to both of you - it was a resistor that I had stuffed in there - I'll remove it and try again tonight.


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## need_a_VR6 (May 19, 1999)

If its a 3.57 board w a 10k leave it, that is fine.


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## ijcameron (May 17, 2001)

need_a_VR6 said:


> If its a 3.57 board w a 10k leave it, that is fine.


The 3.57 is the SMD board (Microsquirt)?

I think I have the v3.0 - it's the second generation of the DIY board


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## need_a_VR6 (May 19, 1999)

Yeah the smd is the 3.57, if you have a v3 you shouldnt need an additional resistor.


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## ijcameron (May 17, 2001)

Thanks for the help - I've removed the resistor and I also reworked the ground and shield wire (they are now grounded with the rest of the MS sensors) - it runs! 

I hear the fuel pump relay occasionally (~ every 5 - 10 seconds) "click" and the RPMs surge, so I'll look at the datalogs tonight to see if there is an issue with the tooth count being reset, or a sync issue.


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