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CAS pull-ups MS3X

MikeSr.

What, me worry?
300+ Club
Joined
May 27, 2003
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Acworth, Ga. USA
Looking at the hardware manual for MS3X, I see the CAS inputs- MS3X cam, MS3 crank. These are ?hall sensor open collector?, so will need pull-up resistors. Unsure of where physically to put the resistors-JP7? In the harness from input to ground?
 
You don't need a pull-up, then. Just make sure there's a jumper on JP3, JP7 and nothing on JP8.
 
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Just trying to sort out after reading the hardware manual and the CAS thread on Tb- much of which disappeared with Gross Polluter’s departure.
The DIY site discussion of Megasquirt-III with MS3X says to set the main board for VR input(?) - I thought the VR circuits are not used.
Quote DIY-“ On a V3.57, put JO1 in the 1-2 position and J1 in the 3-4 position.”
Since I have not opened the box yet, I have no idea what this means or what it applies to hall sensor open collector.
“For a pull-up on the CMP input, make sure JP7 is in place on the MS3X.”
Is JP7 a simple jumper and the 1K is enabled by this? Or is JP7 jumped with a 1K?
“ The CKP also needs pull-up. You can put this in place internally or externally. For an external, run a
1K resistor from pin 26 to pin 24 on the main board.
For an internal pull up on a V3.57 board, solder a 1K resistor to R 57”
Just a little confusing to me
 
I always used 1k pullups built into the harness. don't be surprised if it acts odd running the input into the VR conditioner.
 
I always used 1k pullups built into the harness. don't be surprised if it acts odd running the input into the VR conditioner.
I saw you said not to use VR conditioner in the thread- if I use cam to MS3X input and crank to Main board input with 1K to ground on each- would that work?
 
the ms3x cam input is a vr conditioner as well. I ended up getting an external MAX9926 based conditioner for mine (same deal as the ms3pro and microsquirt rpm inputs). still need the pullups, but you'd wire/solder the outputs directly to the pin inputs on the processor.

the problem I always had with the old vr conditioners was some sort of signal drift (for lack of a better description), timing was unstable at higher rpms and the car seemed 'off' all the time until I made the change, then it started behaving. I've actually run into that a couple of times on a couple different cars, this was the safest (electronics wise) way I found to get around it.
 
Interesting. I figured that drift was a function of timing belt stretch.

This makes me want a Maxxecu even more now...
 
Oh, jeez- I think I screwed the pooch-I removed the two screws holding the black sensor to flip the wheel .
Time for a new CAS?
These:
 
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