# megasquirt trigger angle/edge woes



## dirtytorque (Feb 5, 2008)

have been running MS 2.0 for a couple of month now on my corrado g60 and it is in a reasonable state of tune.
Well so i thought.
As I have now started opening up the throttle a bit I experienced spark knock.
Fine,however I now have a really conservative spark table and it was still knocking.
So I checked my ignition timing with a didgi timing gun and i discovered that even though the advance value for MS is the same as the one seen on the timing gun at idle as soon as I rev the engine they disagre with too much actual advance in affect at a given map/rpm.
I have since put a flat spark table in MS (i.e every bin is the same value) but the timing can still be seen to be advancing on the timing gun.
Soo.. i have been reading about and I have seen that his can be caused by triggering off the wrong trigger edge,or having your spark output reversed.
I am controlling a coil directly at the moment and so have ..
coil charging scheme: standard coil charge
spark output: going high inverted.
I am using stock dizzy/hall using a pullup resistor for the ecu signal
I am using the falling edge for ignition capture.Try as I might the car simple will not start using the rising edge.
trigger offset is set to 30 degrees.
Anyone else on here squirted their g60.
What ignition settings are you using,i.e which trigger edge are you triggering off.
And can you confirm your coil charging schemes?
fyi
Would I be better off using an ignition module from a mk2 car??
using megasquirt 2.88e with version 3.0 board.
thanks in advance.


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## ValveCoverGasket (Mar 20, 2002)

*Re: megasquirt trigger angle/edge woes (dirtytorque)*

i would set the trigger angle to 60 degrees
thats a more "normal" value
otherwise if its being driven directly from the board, the rest of the settings make sense i think...if MS2 uses the same naming scheme as MS1


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## dirtytorque (Feb 5, 2008)

*Re: megasquirt trigger angle/edge woes (ValveCoverGasket)*

ok,but if my megatune and timing gun values match at 30 degrees offset ,they are not going to match at 60 degrees are they ?
Thats not meant to sound narky btw.
thnks for your response.
Ok at the risk of muddying the water hear there is another problem which I think relates to this now.
My g60 coil dosnt like megasquirt at all.
Trust me I have tried four g60 coils and none of them fire.
An audi 80 coil and a mark3 golf gti work fine.
Well I get a spark so I can drive it








I can't be in uncharted territory surely??
Most people on here seem to be running earlier versions of megasquirt.
I wonder if that is the problem??


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## need_a_VR6 (May 19, 1999)

*Re: megasquirt trigger angle/edge woes (dirtytorque)*

That exact problem happens if you have the ignition output inverted wrong, however yours sounds like its set up correctly. You're using the on board driver with no other mods, correct?
Another thing that might be an issue is that your trigger angle should be 10-20deg greater then your max advance. You might be able to change the input trigger edge and re-sync to a higher angle (60) to make it work.
Thats all I have but there aren't many people with MS2 here yet.


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## ValveCoverGasket (Mar 20, 2002)

*Re: megasquirt trigger angle/edge woes (dirtytorque)*


_Quote, originally posted by *dirtytorque* »_ok,but if my megatune and timing gun values match at 30 degrees offset ,they are not going to match at 60 degrees are they ?


youll have to reset where you have your distributor locked down. so set the value to 60, and move the distributor until they match again
regarding the g60 coil not working (i was under the impression that these were just like mk2 8v coils), what sort of dwell time are you running?


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## dirtytorque (Feb 5, 2008)

*Re: megasquirt trigger angle/edge woes (ValveCoverGasket)*

ok,i'll give it another bash.
in regards to dwell I have tried from about 3.5-2.5 msecs?!??


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## need_a_VR6 (May 19, 1999)

*Re: megasquirt trigger angle/edge woes (dirtytorque)*

Sounds about right on the dwell the ABA coil likes about 3.2ms running.


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## ValveCoverGasket (Mar 20, 2002)

*Re: megasquirt trigger angle/edge woes (need_a_VR6)*

http://****************.com/smile/emthup.gif


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## sdezego (Apr 23, 2004)

*Re: megasquirt trigger angle/edge woes (dirtytorque)*


_Quote, originally posted by *dirtytorque* »_ 
...
And can you confirm your coil charging schemes?
fyi
Would I be better off using an ignition module from a mk2 car??
using megasquirt 2.88e with version 3.0 board.
thanks in advance.



To add from our brief discussion in the G60 Forum and the above:
I am running the stock G60 coil using:
6.0 Crank
2.5 Running
0.1 Min Discharge
VB921 (Inverted Spark of COURSE)
I suppose with the T-Angle being screwy it might be possible that there was not enough time to charge the coil. ..or it was causing some strange behavior with the G60 coil.
*Q-1:* EDIT: Oops, see that you posted what codebase you are running?
Most people here are running MSI-extra, but I know of a few that are and have been running MS2 on a str8 G60 setup. In MSI-extra, trigger angles of ~15*-45* are usually bad becuase there is not enough time when the first vane passes and alerts the ECu to get ready to fire till the triggering edge of the vane passes.
*Q-2:* Did you assemble the board or someone else? You should confirm how the Ignition was wired as this can affect the trigger angle as well. For instance: Running MSI-Extra, if you wire the board correctly for the VW Hall Sensor, you WILL end up with a trigger angle of 60* if everything is setup properly. However, if you follow the standard assembly directions (which assumes GM type, etc Hall), then you will end up with a TA of 0* and will be in what is called next Cyl Mode (perfectly acceptable and has pros and cons). Incidentally, this is how mine is setup. This has the effect of rising vs falling edge. In MSI-extra, you can not specify in the software (to my knowledge) rising vs falling and some of the other settings that you have in MS2. So I assume that you can have settings in MS2 that are counter acting other settings and could cause a no spark or very screwy ign issues.
As mentioned, typically the only 3 main causes for timing to go out of whack like you described (Especially when set to fixed timing) is:
1.) incorrect VR sensor Polarity (which you can rule out since you are using Dist/Hall)
2.) Coil/dwell etc being severely incorrect (usually using vb921 and not having it set to Inverted).
2.) Trigger Angle wrong, out of sync ign etc.
Hang in there, i am sure it is something as silly as getting the trigger angle and ignition properties set correctly.
NOTE: anyone can feel free to add or correct anything I mentioned above as I don't consider myself an expert on the subject








Shawn



_Modified by sdezego at 11:51 AM 5-28-2008_


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## need_a_VR6 (May 19, 1999)

*Re: megasquirt trigger angle/edge woes (sdezego)*

Spot on. With MS2 generally you don't need to run the 'next cyl' mode because you can change the ignition input trigger edge. If your board still has XG1 jumpered to XG2 you will be in that situation.


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## dirtytorque (Feb 5, 2008)

*Re: megasquirt trigger angle/edge woes (need_a_VR6)*

I would like to say a HUGE HUGE thanks to you guys for your advice.I apologise for being such a doubting tom.
The car is triggering correctly running at 67 degrees trigger offset on the original g60 OEM coil.








I honestly hadn't read anywhere that I had to target the offset to a particular value.
Oh well I know now.
to answer your questions sdezego I am using megasquirt 2 2.88e
I built the board myself following the MS2 v3.0 instructions . http://****************.com/smile/emthup.gif


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## ValveCoverGasket (Mar 20, 2002)

*Re: megasquirt trigger angle/edge woes (dirtytorque)*

great to hear that its working http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif


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## sdezego (Apr 23, 2004)

*Re: megasquirt trigger angle/edge woes (dirtytorque)*

http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif


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## need_a_VR6 (May 19, 1999)

*Re: megasquirt trigger angle/edge woes (dirtytorque)*

Good stuff. Did you have to change anything else in the software to get that to work? Did it cure the original issue?


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## dirtytorque (Feb 5, 2008)

*Re: megasquirt trigger angle/edge woes (need_a_VR6)*

No all my other settings stayed the same,just the trigger angle and the physical position of the dizzy was all i changed.








All my ignition problems seem solved.With a flat spark table i can now rev the engne and the timing mark stays stationary on the timing gun.
Also the original g60 oem coil now works.







http://****************.com/smile/emthup.gif


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## 81turbocaddy (May 23, 2003)

*Re: megasquirt trigger angle/edge woes (dirtytorque)*

I just read this on the MSextra website, a little late i guess....
"IMPORTANT - do NOT set your total Trigger Angle (i.e. Trigger Angle plus additions) in the range 20 to 50 degrees as you will encounter problems and be unable to get your desired advance. "
looks like this is info for MS1, but I guess it holds true for MS2 also.


_Modified by 81turbocaddy at 10:52 AM 5-29-2008_


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## need_a_VR6 (May 19, 1999)

*Re: megasquirt trigger angle/edge woes (81turbocaddy)*

Good stuff. http://****************.com/smile/emthup.gif


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