Nuts and bolts

[Flat32]

I've got my MSII up and running with a GM TBI, wide band and Megatune doing A/F only. Have a MSD 6A hooked to a distributor with DuraSpark internals. Have made a new distributor using the DuraSpark reluctor and pickup which will be locked, no advances. My distributor cannot be adjusted at it's mount so I'm having to phase the rotor which isn't a problem. Now I have to phase the reluctor which I want to have fixed in a limp home position at around 12 degrees while connected to the MSD without being connected to the Megasquirt. This limp home setup will be with a carb replacing the TBI.

Ignition setup with Megasquirt appears to tolerate any reluctor position by utilizing the trigger offset. If I'm understanding it right a reluctor paddle passes the pickup, triggers the ECU and delays the spark so that it is in advance of the next paddle arriving at the pick up.

Connecting to the MSD the paddle immediately at the pick up will trigger the MSD. The trigger offset instructions aren't clear to me as to whether there is an optimum or a more desirable number. I want the MSII controlling spark using the MSD normally. Can I have my locked 12 degree position? Do I have to use the Extra code? My board is the 3.57.

Ray

[Matt Cramer]

You're correct about how the MS operates. A 12 degree trigger angle and Bowling & Grippo code should work just fine - plus you can set your crank timing to "trigger rise" and get more accurate timing at startup; it'll fire the spark as soon as it gets a signal in that mode.

[Flat32]

Thanks Matt. That covers my nuts and bolts concerns. I went a step further in anticipation of connecting wires and went to MSD specific instructions and found myself in a quagmire of information, as usual with just about all of the Megasquirt/Mega Manual instructions I've dealt with. Seems like all I need to do is connect the direct coil output red wire to the MSD points trigger white wire, but got my brain toasted by mention of a pullup resistor and no clear indication of whether it is needed or not. Do you have any insight on that?

Thanks,
Ray

[Matt Cramer]

There's already a pullup resistor in the MSD box so you do not need to add one.

[Flat32]

Thanks again Matt. Nice clear answer made my day. Fired up the laptop, opened Megatune (2.25 p3) and clicked on ignition options. Faced with a window load of options that is different from the window in the Megamanual instructions and 8+ pages of "stuff" that appears to be ignorable for the most part with my installation. Is there a dummy guide for all of the ignition option settings when using the MSD 6A 6200 box and the Megatune 2.25 p3 software? I get trigger offset, don't get skip pulses and started to cry when I started reading about predictor algorithm.

BTW, my car is a 1932 Ford coupe running a flathead engine and is my daily driver, but I drive it Seattle, WA to New Jersey and back yearly. I drag race it and seek optimal horsepower when racing and optimal mpg going cross country. The Megasquirt can handle the job, but I'm very concerned about having it set up so there're no ragged edges or looming quirks from having wrong settings.


Ray

[Matt Cramer]

I generally recommend much the same settings you'd use for direct coil control:

http://www.megamanual.com/ms2/vb921.htm