Triggering on an LT1

[BaldTurboFreak]

I finally think I have solved the lt1 dilemma for those that are still in need of the stock ecm.
I have progammed my entire maps (all of them including minumu and maximum advance) with 40Deg. Kinda of like making a locked dizzy out of it. then Im triggering MS off the ignition control wire, and triggering the factory ignition module from the ms igniton driver.
This allows for full ignition control, along with full fueling control, but keeps the factory ecm in place and still talking to the rest of the car's computers (CCM ABS,Dash etc)

[whynot]

I was wanting to get a fast xfi box, but funds just ran short, so what is it going to take me to get it up and running with a mega squirt 2 3.0.

keeping the stock pcm to controll things like ac, speedo, other misc things, basically everything but the engine. does anyone have it figured out how to read off the opti, for timing and fuel. and what other things will I need. I am getting a wide band o2 as well.

[BaldTurboFreak]

The factory ecm is doing the decoding of the opti for you. You will need to have access to the factory chip or in my case (95) flash to "lock" the advance in at a predetermined trigger angle. In my case 40 deg. then you tell the mega squirt the the trigger angle is 40 deg. Then it's basically setting it up for a locked distributor and 4 pin module. You cant share the thermistors (IAT,CLT) so you'll Either need some dummy resistors for the PCM or in my case just ran 2 sets so my digital guage functions still work correctly.

[whynot]

ok, since I have a 93 and I am not going to swap it out for later, that pretty much puts me at a pickup wheel, right?

so with that, what can I do to fire seperate coils for each cylinder without the stock pcm or opti?

or mabey better yet, what is the quickest and easyiest way to run an lt1 on mega squirt? because I will probably buy the whole thing assembaled.

and with the whole engine disengauged, will the stock pcm still run the ac, and the speedo? anything else it is needed for?

[BaldTurboFreak]

Okay there have been a few Changes,
Set the trigger angle on all tables in the factory ecm at 60 deg advance, and the same with megasquirt.
At this point I have used the Tach signal wire from the factory ecm instead of the factory ignition control wire, due to the stronger 12V squarewave (the ignition control wire is 5v square wave).
Im triggering the factory module using led 17 and a pullup resistor. So far so good. I havent got a pointer on my ATI balancer yet so until I degree wheel one in I wont do any Dyno pulls. The greatest thing about using it like this is that the factory ecm is happy, and factory knock retard will function seamlessly thru the MS.
I cant wait to hear it spool up under boost!

[BaldTurboFreak]

Im not sure if it's going into limp home or something but, Ive locked out all factory timing tables to 60 deg advance and Im still seeing a "curve" come out of the factory ignition control wire. Im not sure how to get around this one. Im so frustrated with it Im ready to go back to factory timing control.

[BaldTurboFreak]

I have had nothing but trouble with the timing, it seems that a defaut curve will lay in despite what you lock the timing to in the programming. Perhaps the factory ecm is going limp home. In either case I have since tried using the mega as a boost retard with limited suck-sess and have elected to go with a 60-2 trigger wheel and ford VR sensor. Im wiring up a pack of Gm 2 post coils for it and going WS.

[bansheeboy420]

have you tried checking the headlight fluid?