# Alternate (and EASY!) Mods for MS V3 and VW Hall Sender Trigger



## need_a_VR6 (May 19, 1999)

_Background_

There are more then 'quite a few' ways to modify Megasquirt main boards to work with the VW hall sender. Most of them involve cutting out components, and adding multiple jumpers and resistors to use the opto circuit. This will use the VR input circuitry with only two jumper wires.

_Applies to_

Anything with an electronic VW distributor (older 8v, 16v, etc)

_Not covered_

Spark output wiring/choices, etc.

_Required_

You need to be using a V3 board (though this would apply to a 3.57 I'm not bothering to cover it at the moment!)

_Procedure _

Build board to normal B&G specs.

Install Jumpers:

Tachselect to VRIN
VROUTINV to TSEL

Make sure R52/56 are both fully CCW (until they click)

_Hall Wiring_

TPS VREF for hall power
Hall signal on Pin24 (Tach)
Ground to cylinder head/MS/etc

_Generic Settings_

MSnS/Distro Mode active
Trigger Angle = 60

Details on the rest of the exacts will vary with MS1/2/3 but that's enough to get most going. 

Enjoy!


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## Prof315 (Jan 5, 2009)

Great stuff Paul and THANKS! I'm going to be doing an SCCA ITB Mk2 digi car at the end of the year and since the IT rules don't allow the addition of a crank trigger (my usual way of doing things) this will make life simple for me. 

Just one question... no pullup needed if you use VRIN?


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## need_a_VR6 (May 19, 1999)

No problem. 

No pullup at all. The car that I was working on had an ABA in it, with crank trigger VR combo. That got ditched for a 9A with the stock distro and I switched it to hall with NO board mods. Just used the ones I normally use for the VR sensor and just changed the few things in the software.

For those using MS2/3 you can use VROUT instead of VROUTINV, but you need to switch the input trigger edge (I believe to rising).


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## ValveCoverGasket (Mar 20, 2002)

need_a_VR6 said:


> For those using MS2/3 you can use VROUT instead of VROUTINV, but you need to switch the input trigger edge (I believe to rising).


the matching of those two was the confusing part... as i seem to recall


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## need_a_VR6 (May 19, 1999)

Yeah especially on a crank trigger where you can also invert +/- signal as well.


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## Luv_My_VDub (Mar 25, 2010)

"Make sure R52/56 are both fully CCW (until they click)"

How sensitive is this? If the pots click, then go a little further, do they need to be brought back around til JUST when they click again?


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## Prof315 (Jan 5, 2009)

Luv_My_VDub said:


> "Make sure R52/56 are both fully CCW (until they click)"
> 
> How sensitive is this? If the pots click, then go a little further, do they need to be brought back around til JUST when they click again?


No you're fine, once they click it's hit a cam and stays fully CCW


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## Sr. Karmann (Feb 5, 2009)

Paul, got everything working with the setup above, finally... although I did have to turn R56 pot 6 turns. Sound advice, Shawn kind of pointed me to this  Funny tho cause his was working on the stim and not in the car, mine case was stim only, thus far, install should happen sometime this week.

This is a MSII V3.0 setup going on a stockish G60 and I have a registered version of TS

What I don't understand is settings in TS for dizzy, it is not selectable in the populated list in Tach input/Ignition settings. Am I missing something when you say MSnS/distro mode: active???


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## need_a_VR6 (May 19, 1999)

My settings are for MS1/Extra, MS2 won't have a setting like that one 

Glad you got it working though!!

The is ONE car I've run into that this setup didn't work on. Was just a 16v swap into a MK1, stock distro, etc. For some reason no adjustment could make it work and I even built another ecu for the car and couldn't get that to work. Swapped it over to the old hall mods and it worked fine. So I'm batting about 19/20 personally with these mods.


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## Sr. Karmann (Feb 5, 2009)

need_a_VR6 said:


> My settings are for MS1/Extra, MS2 won't have a setting like that one
> 
> Glad you got it working though!!
> 
> The is ONE car I've run into that this setup didn't work on. Was just a 16v swap into a MK1, stock distro, etc. For some reason no adjustment could make it work and I even built another ecu for the car and couldn't get that to work. Swapped it over to the old hall mods and it worked fine. So I'm batting about 19/20 personally with these mods.


Those are pretty good odds, you still have an "A" :laugh:

What would you recommend as a setting for Tach Input selection? :beer:


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## Luv_My_VDub (Mar 25, 2010)

hang on, so those settings at the top of the post won't work if i'm running ms2?
I was wondering why there was no 'distro mode active' setting. i
I just used the 'distributor' setting that's in the list.
could this be why my car still isn't running?


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## Sr. Karmann (Feb 5, 2009)

Luv_My_VDub said:


> hang on, so those settings at the top of the post won't work if i'm running ms2?
> I was wondering why there was no 'distro mode active' setting. i
> I just used the 'distributor' setting that's in the list.
> could this be why my car still isn't running?


Try R56 pot a few turns 

http://forums.vwvortex.com/showthread.php?5148658-MS1-to-MS3


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## sdezego (Apr 23, 2004)

need_a_VR6 said:


> My settings are for MS1/Extra, MS2 won't have a setting like that one
> 
> Glad you got it working though!!
> 
> The is ONE car I've run into that this setup didn't work on. Was just a 16v swap into a MK1, stock distro, etc. For some reason no adjustment could make it work and I even built another ecu for the car and couldn't get that to work. Swapped it over to the old hall mods and it worked fine. So I'm batting about 19/20 personally with these mods.


Paul, did you happen to look at the Op amp and the few other pieces of hardware that changed in the BOM from -> http://forums.vwvortex.com/showthread.php?5148658-MS1-to-MS3/page2. Just wondering if maybe you got the older op amp on that one or what. Would be nice to narrow it down definitively, but like you said 19/20 a'int bad


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## need_a_VR6 (May 19, 1999)

Nope it's all newer stuff with both the ecu's I tried. It could have easily been a power/ground/evil spirit problem in the install car though.. it had CIS and actually ran well with it and the car might not have been into the MS swap


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## Luv_My_VDub (Mar 25, 2010)

tried turning R56 a few turns either way. Only thing that happened was that I lost rpm signal. Turned it back fully counter clockwise and got back rpm.

the setting is actually 'basic trigger', not 'distributor'. Everything is set right as far as I can tell. Nothing seems to be getting this car to start =/


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## need_a_VR6 (May 19, 1999)

If you have rpm you have an output problem.


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## Sr. Karmann (Feb 5, 2009)

revisiting this with another MS3X build I finished today, got the kit from DIY yesterday and the pots don't click on R52/56 turned a ton CCW.

I have another build that was underway from awhile ago, I am going to check those pots later this afternoon. The ones from the older kit are blue, whereas the ones from the latest kit are grey.


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## ValveCoverGasket (Mar 20, 2002)

dont be too alarmed by that, just count off ~30-40 turns. ive noticed some of them dont click, the grey ones as you said, their resistance values are still good though :beer:


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## Sr. Karmann (Feb 5, 2009)

ValveCoverGasket said:


> dont be too alarmed by that, just count off ~30-40 turns. ive noticed some of them dont click, the grey ones as you said, their resistance values are still good though :beer:


30-40 from where? I've turned them A LOT, CCW, and even back CW to see if I could get a click

:beer:


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## ValveCoverGasket (Mar 20, 2002)

from where ever its at, although by now it sounds like youve probably already gotten it to 0 so i wouldnt worry about it.


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## need_a_VR6 (May 19, 1999)

Grey ones don't click from what I remember. Also if you have trouble try a pullup resistor to hall supply voltage. I had two that wouldn't work off the bat and that fixed it.


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## Sr. Karmann (Feb 5, 2009)

ValveCoverGasket said:


> from where ever its at, although by now it sounds like youve probably already gotten it to 0 so i wouldnt worry about it.





need_a_VR6 said:


> Grey ones don't click from what I remember. Also if you have trouble try a pullup resistor to hall supply voltage. I had two that wouldn't work off the bat and that fixed it.


:thumbup::thumbup:


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