MS2ex lost sync random

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ttbrendan
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MS2ex lost sync random

Post by ttbrendan »

I have ms2/extra V3. running sbc with 8 ls2 coils, AEM dual sync distributor, twin turbos, low imp 83# inj, waste spark conf.

Car is running but get a random lost sync. The composit log shows that my crank signal goes hi and stays high. The crank and cam are hall/optical sensors 12v. Running them into ms2 thru the vr ports. Running a shielded wire and ran it away from any other wires.
In the log it seams that there is an unrecorded lost sync right in the begin where the ecu toggles back to crank mode for a split second. Then later it trips a lost sync.
I think the lost sync reason is 17 but cant find anything on it.

Brendan
Attachments
2017-11-26_13.39.37.msq
Current tune
(120.18 KiB) Downloaded 20 times
2017-11-18_11.41.13.csv
Bad composit log
(178.22 KiB) Downloaded 20 times
2017-11-26_12_modified2.msl
This is the latest log I started log after warmup.
(368.94 KiB) Downloaded 20 times
ttbrendan
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Re: MS2ex lost sync random

Post by ttbrendan »

The dual sync distributor is 24+1. Here is a good composit log.
Ok so I found that error 17 has something to do with 2nd trigger not seen when expected, but if crank signal isnt right then it can trough a 11 or 17 error. I'm only getting 17. Is this something the vr trim pots may help. I thought using hall/optical sensor that the trim pots wouldn't do much, is that wrong?
Attachments
2017-11-26_12.34.54.csv
(289.53 KiB) Downloaded 17 times
rickb794
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Re: MS2ex lost sync random

Post by rickb794 »

Are pull ups needed or not?
Rising or falling edge may not be set correct?
An MS2 only has one VR channel, please correctly identify your hardware. (What is MSExtra340t2?)
You can use the opti conditioner circuit with a hall sensor for the single tooth input.
For the dual distributor you need two input conditioner circuits connected to the correct MS2 ports.
Correctly identify your MS ecu here
Read the Do's and Don'ts to avoid the common pitfalls before starting your install or asking for help
Use only these manuals other manuals may cause brain damage or worse.
ttbrendan
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Re: MS2ex lost sync random

Post by ttbrendan »

Thanks in advance for any help.

I'm running a ms2/extra with 3.4.0 release. V3.0 board, LED mod for wasted spark, gm stepper iacv

The crank and cam signal are 0-12volt square wave. Crank signal is going to the optical input and the cam is through the vr input. There doesn't seem to be a problem with the cam signal but, crank signal goes high and stays there randomly. I believe that this happen more when trying to rev the engine,goes bad car can run until warm and then when I press on accelerator and that is when signal goes high.
I was reading about a higher capacitor (C12 .001uf) value may be need in optical circuit if there is excessive noise. Does seem like a good place to start?

Brendan
rickb794
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Re: MS2ex lost sync random

Post by rickb794 »

The optical conditioner circuit does not like high frequency signals.
A 24 tooth wheel should not over tax it.
The opti isolator generally works or it doesn't, how is yours modded for hall use?

Is it possible you have a problem with the sensor it's self. Is it a common sensor so you can substitute a spare?
Correctly identify your MS ecu here
Read the Do's and Don'ts to avoid the common pitfalls before starting your install or asking for help
Use only these manuals other manuals may cause brain damage or worse.
DaveEFI
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Re: MS2ex lost sync random

Post by DaveEFI »

If you have scope, look at the signal in and out of the opto sensor.
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rickb794
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Re: MS2ex lost sync random

Post by rickb794 »

Again, you can't just plug the hall output into the Opti circuit.
The Opti circuit needs some adjusting.
I use the method that "unaclocker" documented for the Neon hall sensor.
It is the method shown for MS1 with a different resistor (1.5k) and both caps (C30 & C12) removed.
(this was for 5v but should also work for 12v) (Note: both diodes are bypassed no connection to "optoin")
(also note that the input should go to which ever sensor, and output should go to which ever CPU pin is appropriate for your install)
Image

For whatever it's worth, the engineering staff has indicated it is preferable to use the Opti circuit for the cam side and the VR for the crank,
because the cam signal is not as critical and the VR handles the higher frequency crank signal better.
I never understood why they made the switch to the VR conditioner because up to a 36 tooth wheel seemed to work fine with the opti circuit.
I think it was to make the setup uniform for all wheels.
Correctly identify your MS ecu here
Read the Do's and Don'ts to avoid the common pitfalls before starting your install or asking for help
Use only these manuals other manuals may cause brain damage or worse.
ttbrendan
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Re: MS2ex lost sync random

Post by ttbrendan »

Is it possible if I just swap the cam to the opto circuit and put the crank on the vr curcuit that it may work? It would be the preferred method anyways correct?
Then I can redo the opto cicuit like mention by Rickb.

As of now I have
Tachselect to optoin
spr1 to vrin
optoout to Tsel
vrout to js10 with a R.984k
also xg2 jump to xg1

I built this board almost 8yrs ago so I'm a little rusty on why I did it the way I did. The notes I have refer to the v3 board assembly from 2008 on hall sensor input.

Thanks
rickb794
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Re: MS2ex lost sync random

Post by rickb794 »

If you have a jumper across the XG's it does not sound like you have the recommended mod done to the opto input circuit.

The opto circuit will probably work just fine for the crank signal if you do the mod above
Correctly identify your MS ecu here
Read the Do's and Don'ts to avoid the common pitfalls before starting your install or asking for help
Use only these manuals other manuals may cause brain damage or worse.
ttbrendan
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Joined: Mon Aug 31, 2015 2:19 am

Re: MS2ex lost sync random

Post by ttbrendan »

I know I don't have what you mentioned so maybe I'll try that first.

Pulling 5volt in from proto area is ok even though I have 12v coming in from my sensor signal?
rickb794
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Re: MS2ex lost sync random

Post by rickb794 »

ttbrendan wrote:I know I don't have what you mentioned so maybe I'll try that first.

Pulling 5volt in from proto area is ok even though I have 12v coming in from my sensor signal?
Not sure, I believe the Opto circuit changes state when the hall output goes to zero.
To me the two states are zero and non zero, not sure the non-zero level is critical.
However one would not want to overdo the reverse voltage applied to the LED.
That would point to a balanced non-zero to forward level.
The data sheet for the 4N25 says 3volts reverse. (might need a larger resistor for 12v)
Maybe someone who had a hand in that circuit design can speak to that.
Correctly identify your MS ecu here
Read the Do's and Don'ts to avoid the common pitfalls before starting your install or asking for help
Use only these manuals other manuals may cause brain damage or worse.
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