Megasquirt Support Forum (MSEXTRA)

I built my ms2 on the version 3 board years ago and ran it with a throttle body and a VR sensor Mopar distributor. Now I have bought the MS3X parts and have it up and running on the jimstim and the stimx. I am testing it with the dual wheel missing tooth 36-1 setup with the dip switch 3 of the jimstim on all others off.

My plan is to use a FAST dual sync distributor. This distributor has hall effect sensors for both crank and cam triggers. It puts out 8 crank pulses and 1 cam pulse per distributor rev. I have tried different things to get the distributor to control the MS3X without success. I hope to jump the distributor outputs into the jimstim and stimx and run it on the bench driven by a drill. I would think that setting up the jimstim for the 4-1 crank input should work.

I went back through my assembly instructions and found that when I built the MS2 I did the jumpering to set it up for the VR sensors but not the hall effect mods. It seems likely that I should go back and add the mods to get the hall effect inputs working. It looks like I can add the hall effect mods without removing the VR mods and it will still work. Just looking for confirmation before I tear into it again. Thanks for any help you can supply. Bill

Is there a good reason not to use a crank mounted trigger wheel and sensor for your tach signal? The dizzy can provide he cam signal.

I know that front mount trigger wheels are very popular with Megasquirt installers. Unfortunately the front of this engine is a very busy place. This not being a HIGH performance engine it seems, at least mechanically, to be easier to just install the dual sync distributor and use the 2 hall effect sensors in it. I think that once I get the details ironed out it should be a good system.

On thinking it over it may be best to set up in TS for 8 crank pulses and 1 cam pulse at the CAM location in the ignition and trigger wheel setup. It seems to me that setting it up for 4 pulses at the crank would require 1/2 pulse at the cam and that seems wrong.

Thanks for your input. Bill

flatbill wrote:I went back through my assembly instructions and found that when I built the MS2 I did the jumpering to set it up for the VR sensors but not the hall effect mods. It seems likely that I should go back and add the mods to get the hall effect inputs working.

If you check the current manuals you'll find that both hall and VR inputs use the same circuit (the "universal tach input") but you'll need to adjust the pots as per the manual and probably add a pullup resistor.

James

James, I have looked up the current assembly manual data and will be getting a few parts I need to make the mods and adjust the R56 pot. I will also do the old mods for the hall effect input on the main board. I don't know if it is necessary, but I don't think it will hurt.

Then I'll try again to use the dual sync distributor to run the MS3X.

Thanks. Bill

For clarity a MS3X board is an expansion board for a MS3 processor.

If you are using a MS3 processor you should be posting in the MS3 section of this forum.

rickb794, I am using an version 3 board with the ms3 daughter board and the ms3x expansion board. Does that mean I am in the wrong place? If I am wrong please redirect me. Thanks, Bill

If I am in the wrong place is there to move this thread to the correct place? Bill

Do you understand that there is little to "mod" in going from VR to Hall? Install the pull-up jumper for the MS3X, slips onto header JP7), and solder in a pull-up for the mainboard CKP tach input. And, adjust the (four) pots per manual. If you have or intend any wiring mods more complicated than those two pull-ups, please explain.

I gotta ask... you aren't trying to use the Megamanual, or some other instructions other than those linked-to above, are you? I'm trying to remember from your other thread if you are trying to follow an article from DIYautotune; I'll go peak now...

OK, as I understand it you built it for VR. There is nothing to remove going to Hall, just pull-ups to add.

W talked about this before: I don't think 4-1 is what you want for the CKP, you don't have a missing-tooth wheel there. Did any one of the experts ever post a definitive setting for you to use?

PS: I peeked at the old thread again. Wasn''t 8 teeth at cam speed for the primary wheel considered to be your simplest-to-understand setting? How did 4-at-the-crank and 1/2 at the cam sneak back into this thread? And no, if you want to set it for 4 at crank speed, the cam is still simply a "1-tooth" at cam speed. No "1/2 tooth" involved.

OK, Here's where I am currently. Per the suggestion received I have studied up on the CURRENT manuals. Big surprise, things were different. I am headed out of town and will not be able to play with it for about a week but things are looking pretty good from my newbe perspective. Here's what I have now.

I went from the newest manual and did the pullups and adjusted all 4 pots and checked all else that I could find.

Ignition/wheel decoder settings;
Tooth wheel
dual wheel
trigger wheel to 8, matching the 8 crank pulses per distributor rev
main wheel speed to cam
second trigger active falling edge
+ every rotation of the cam
one cam pulse per distributor rev

I have my dual sync distributor hooked up as follows
+12 v picked up from 12v screw terminal 29 on the jimstim
ground picked up from the ground pin at the corner of the jimstim
crank signal from distributor to the primary tach pin on the jimstim closest to the power switch
cam signal from distributor to the cam pin on the stimx
5 v from jimstim 5 v pin to 5 v pin on stimx

With all this laid out on the bench and the distributor driven by my drill I can run the system and watch all the guages on TS and all the led's on the stimx are blinking in what seems like a reasonable fashion. I can run the distributor speed up and down to watch what's happening.

When I get back in town I'll do some more logging and post the results.

I feel confident that, while I will still have to do some tweaking as I install the system on the car that I'm close to getting running. Thanks for all the help I have been given. It is much appreciated. Bill