Triggering with Ford hall sensor and distributor

[murkurycapri]

Hello all,
Brief introduction, I have an 1985 Mercury Capri that I am in the process of a 351w swap on, gonna be running a 70mm single turbo. At the stage where I'm starting to put the motor together, so its time to start thinking about my wiring.

Ill try to be as direct and to the point with this, attached is a VERY simple block diagram on how I plan I triggering the microsquirt. The distributor is the one which came on my motor, out of a 1996 ford f250. As the diagram shows, I plan on using the hall/shutter wheel within the stock distributor to trigger the micro. From there, the ignition out from the micro will go on to trigger the MSD ignition box, which in turn the coil. I like this setup the best for 2 main reasons. One, I can use the micro to turn spark on and off, which is good for boost building (If I used a factory style TFI setup, I cant) and Two the MSD box as its own rev limiter that can be set. In other words, its a failsafe. If for some reason I screwed my settings, added an extra zero on my rpm limit, whatever, that MSD set limit will act as a safety net and never let the motor spin fast enough to immediately self destruct.

My biggest issue I noticed is this. The 8 tooth shutter wheel in my factory distributor has one uneven gap. I'm assuming the factory EFI was sequential injection, with the uneven shutter being the identifier for cylinder #1 or something.

Can I still make this work? Can settings be changed to account for this one uneven window in the shutter wheel? Or do I need to try and find a new shutter wheel that has all even spacing (If that even exists for this distributor)

Sorry if this was answered before, but the search on here and Google didn't return anything that really answered my question...

[Bernard Fife]

mc,

Check to see if one edge or the other of the teeth is evenly spaced, as often they are and one tooth itself is bigger or smaller than the rest. If one edge of the teeth is symmetrical, then you can select the appropriate edge of the signal (rising or falling edge) in the software to get a proper signal.

See 'Ignition Input Capture' here: http://www.megamanual.com/mt29.htm#ib .

Lance.

[murkurycapri]

Thanks, that answered my question perfecty!