A basic MS ignition question

[DaButcher]

Hi, I have a basic MS Ignition Question.

When reading the manual, it says:


Spark Output (spkout_hi_lo) 0 equals spark when low (ground). Production MegaSquirt-II's do not have a transistor for ignition control on the daughter card. This transistor inverted the processor output on the beta units. As a result, if you are using a production MegaSquirt-II and NO transistor, the Coil Charging Scheme needs to be reversed.

You should set the spark output such that no current flows through the coil when the rpm=0. To do this, replace the coil with an LED tester (see step #6).

Setting the spark output one way should result in the LED being off with no rpm - that's the way you want it. If It is on, the coil is flowing current all the time, and it will overheat, and the ignition module (or VB921 or BIP373) may overheat too.

So, this means I should pull out one of my COP's and measure for volts with ignition on?
Ps. I have a problem that I'm blowing the fuse for ignition/o2.

So, I just measure or use a lightbulb..
If it is hot when RPM = 0, this means I have to invert the spark output, right?

Ps. I'm WS on the motronic powerstages (volvo 960)

[chenz]

I don't understand what a COP is. But I can suggest to use your multimeter to find out what's drawing enough current to blow the fuse, something may well be getting hot in the board as it draws the current. Check there are no solder bridges making a short. Even with the case itself

So, I just measure or use a lightbulb..
If it is hot when RPM = 0, this means I have to invert the spark output, right?

This is correct, because when the globe is lit it will be charging the coil. There are only 2 options so if it's not one it's the other. But do test both to be on the safe side.

If it is hot with no RPM then you get cool lightening rods from the coil but it does not do any good for your megasquirt. Believe me I know :-D

[fryea]

unplug ALL of the COP's and then test, otherwise you could fry all but the one you unplugged if you picked the wrong setting.

From my experience, if you are triggering an external module (bosch 139, coils with built in ignitors) then the spark output is NOT inverted.

If you are using internal ignitors (VB921's, BIP transistors) then the signal IS inverted. YMMV, be sure to test with an led or whatever method works.



If it is hot when RPM = 0, this means I have to invert the spark output, right?

bingo

[DaButcher]

I don't understand what a COP is. But I can suggest to use your multimeter to find out what's drawing enough current to blow the fuse, something may well be getting hot in the board as it draws the current. Check there are no solder bridges making a short. Even with the case itself



This is correct, because when the globe is lit it will be charging the coil. There are only 2 options so if it's not one it's the other. But do test both to be on the safe side.

If it is hot with no RPM then you get cool lightening rods from the coil but it does not do any good for your megasquirt. Believe me I know :-D

COP = Coil on plug.

I took and cranked it with inverted output, now it doesent blow a fuse.
Only issue now is that I cant see in megatune that It's cranking, also it shows 0rpm.

I believe I will have to adjust on the two pots..
Seeing as I dont have a garage or a garden, or a private parking space, it's kindof a hassle to dis-assemble and assemble the interior each time I give the MS a try :P So, yes.. I might test it within a couple of days, or I might just let the MS rest in peace for a while.

It would be super to have a male and a female motronic55 connector, so I could plug in the ms without removing the motronic and then just check signals, etc.

[DaButcher]

unplug ALL of the COP's and then test, otherwise you could fry all but the one you unplugged if you picked the wrong setting.

From my experience, if you are triggering an external module (bosch 139, coils with built in ignitors) then the spark output is NOT inverted.

If you are using internal ignitors (VB921's, BIP transistors) then the signal IS inverted. YMMV, be sure to test with an led or whatever method works.


bingo

yes, I will have to test this..

[crazy0000]

With my setup(VR and bosch 139) It runs with spark output inverted... Doesn't run very well with it not inverted.

[DaButcher]

With my setup(VR and bosch 139) It runs with spark output inverted... Doesn't run very well with it not inverted.
ok..
I dont know if mine work the same.
I run 0 227 100 203 powerstages (volvo 960 ones - stock), as my COP's dont have built in ignitors. I guess I could maybe measure today.. I will then have to dis-assemble the interior again, as well as the plastic cover above the coils.

Then I can first measure with motronic and ignition switch in position 2.
Then I can put in the MS and measure...

The weather is nice today.. However, I will need to fix the RPM issue too..
Also I'm not sure about the injector setting that the poi was running, as he had not activated the bank 2 for injectors in the msq... My plan is firing the injectors alternating, but we will see how it goes :-)

[DaButcher]

I have now adjusted the pots.
Did some measuring before adjustment and this is the result:

200K ohm scale on multimetre
R52 WAS 46K ohm NOW: 9.72
R56 WAS 0.06K ohm NOW: Unchanged

I turned them both counter clockwise, as per the manual.
Then I will try and crank, look if I get rpm and try adjusting the R52 clockwise.

[DaButcher]

It started!! Yey!

More info here:
http://forums.turbobricks.com/showthread.php?p=1987627#post1987627