MS1 to Mallory ignition

[Orange65]

While doing some research into my eventual swap to EFI, I have a couple of questions. I have a Mallory Promaster billet distributor (hall effect) feeding a Mallory 685 control box. Currently, I hook the distributor into the green and purple wires on the 685. To supply the RPM signal to the MS1 (version 3.0), I am not finding much info that is Mallory or 685 specific. I have found that the MSD 6 using a hall effect is rewired so that the distributor wires are fed into the MS on pin 24 and pin 37 feeds the MSD 6 on the white wire. Will this be the way I need to wire my Mallory?

I am going off of this section in the Megamanual:

http://www.megamanual.com/ms2/msd6a.htm

Also, I bought the MS1 prefabbed from DIYAuto about 10 years ago (not one to rush into anything ). The instructions on the Megamanual says to follow steps 50-52 in the assembly manual. How much of this was done when it was made and how much do I need to go back and do?

Thanks.

[Matt Cramer]

A preassembled MS1 is going to need mods. For a Hall effect distributor, see these links:

http://www.msextra.com/doc/ms1extra/MS_Extra_Ignition_Hardware_Manual.htm#hall

http://www.msextra.com/doc/ms1extra/MS_Extra_Ignition_Hardware_Manual.htm#msdout

[Orange65]

Thanks for the links Matt. I have been studying them and have a question. The hall effect sensor shown in the drawings has 3 wires- mine only has 2. How would I hook that up? The instructions with the distributor just call it a + wire and a - wire.

BTW- I am not sure if I mentioned this before- I only want to control fuel with this MS1- no ignition if that makes a difference.

Thanks in advance.

[TheSilverBuick]

Hall effect sensors typically have 3 wires and VR sensors have 2 wires. Are you positive it's a hall effect sensor? Pictures perhaps?

[Orange65]

I think I found my answer on DIY Autotune's page:

"MSD offers several types of distributors. Here, we'll focus on the familiar billet distributors, the kind with two wires coming out. MSD calls this a magnetic pick-up; the MegaManual calls it a VR or variable reluctor sensor. Some MSD distributors have built in modules or behave like various factory distributors; these include the Ready To Run series, the Optispark replacement, E-Curve, and HEI distributors. Here, we'll cover the billet magnetic pick up distributors, as well as the Flying Magnet crank wheel.

Note that if you're running fuel only with the Megasquirt and the distributor is controlling the timing, just run the MSD tach output wire to the Megasquirt pin 24 and use the Hall / optical input circuit."

Mine is a magnetic pickup and I only want to run fuel, so looks like I can pull the tach signal from the Mallory 685 and feed it into the Megasquirt on pin 24 after making the modifications for the hall/ optical input circuit. Now just to find out which mod- for a high to low, low to high, +5V or +12V....