Question about ms/mj (crank sensor)
Turbo Mini Forums

So, Have i understood correctly that with this system, there isn't a setting that allows you to 'dial in' a crank sensor offset?

Instead you have to dick about moving your sensor around to just the right spot in order to 'zero' the TDC reference...

Anyone confirm?

I don't know about mj but for ms you just need to tell it the value of the offset.

There are some restrictions depending on the type of crank sensor and the code you're using. For example with MS1/extra, you may not be able to have the offset between about 10 degrees BTDC and 30 degrees BTDC (not sure about the exact values) because that screws with the "next cylinder" and "this cylinder" algorithms. Let me know if you want me to elaborate on this.

So, the short answer is that in most cases you just need to input the offset value in the configuration software.

Jean

http://www.jbperf.com/

Just occurred to me that mj is EDIS only so it will require a specific offset as will ms if you're using EDIS. The offset is 90 degrees BTDC cylinder 1 (as far as I remember) meaning that the missing tooth will be 90 degrees past the VR sensor when the engine is at TDC cylinder 1.

This is due to the EDIS module requiring this offset and this is hard coded. mj/ms can't do anything about it since it doesn't even receive the VR sensor signal.

Jean

http://www.jbperf.com/

I'm now somewhat more confused!

What is /are the following - as far as based upon / similarities / etc...

Megajolt
MegaSquirt
MegaSuirt1/extra
MegasquirtnSpark

Edited by TurboDave16V on 30th May, 2006.

Megajolt (actually Megajolt lite junior) is ignition only (with some spare inputs/outputs) that uses the EDIS module and associated hardware (VR sensor, 36-1 wheel, coil pack). The hardware is completely different from Megasquirt and not done by the same people.

Megasquirt is the ECU and can be based on either the v2.2 board or the v3.0 board. It can have the MS1 processor (68HC908 ) or the MS2 processor (daughter board with MC9S12C64).

Megasquirt1/extra is the new name for MegasquirtnSpark-extra and is the firmware that runs on MS1 with a lot of features not initially on the original MS1 code. It has been renamed because there is some development underway to port some of the features to MS2 and this code will be names MS2/extra.

To make things a little more confusing, MS2 also refers to the code running on the MS2 processor because up to now there has been only one official cade on that processor.

MS1/extra and MS2 can both do fuel and ignition. They also can both do EDIS-based ignition (with a 36-1 wheel) or crank trigger (with a variety of wheels). MS1/extra has up to 6 ignitions outputs but MS2 currently only has a single ignition output. MS1/extra can also use a cam trigger in addition to the crank trigger but MS2 can't.

For more information you should really go to the megasquirt site. There's a lot of information there so that makes it a bit overwhelming at first but going through it a few times will make things clearer.

Hope that helps.

Jean

http://www.jbperf.com/

Hi,
Jean .... From what you're saying there, the MS1/extra is the one to go for... As in you can use a cam sensor and maybe the rover 36-2 trigger pattern?
Unless it's short of injector outputs?
Cheers,
Gavin :)

Edited by Bat on 30th May, 2006.

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AlexF

Yes, it is a simple matter to add a degree or two to every value in the map to correct the misalignment.

Or if you use one of my brackets, it has been designed to be spot on so no worries!

As long as it's a few degrees, it's ok. But more than that and you may run into problems if the EDIS module loses the connection to mj/ms. In that case it returns to the limp mode which does a constant 10 degrees of advance. If you're off by more than a few degrees this will not be 10 degrees and could cause problems.

http://www.jbperf.com/

Hi,
Dave, I've been doing some reading up on this. From what I can see the MS n S extra is the one to go for.
The MS has 4 injector outputs and you add an extra socket to the box, connect your crank sensor and upto 4 coils to your extra socket, will do coil on plug if your that way inclined.
You can then setup your sensor offset with the software instead of dicking around!
If I'm wrong, can someone put me right?
Cheers,
Gavin :)

Edited by Bat on 31st May, 2006.

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Dave, just get a 36tooth wheel - none missing, make a sensor bracket with say 5mm of adjustment to fit in a "convenient" place, set it up as per the guides on http://megasquirt.sourceforge.net/extra/edis-hardware.html then cut off the relevant tooth.
You can have a butchers and the MS ECU of mine next time you're over here if ya want.
Rich

Dave,

If you are using the EDIS then for obvious reasons you do have to dick about. However there are lots of settings for other trigger wheels. Have a read of:
http://megasquirt.sourceforge.net/extra/setup-wheel.html
That should tell you all you need to know.

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