I now have in my possession eight GM LS1 coils with brackets and harnesses. My plan is to use an ECM out of a 1994 Cavalier with a 2.2 liter engine, this decision was made because the 94 cavalier was a multi port injection setup and uses a knock sensor. Neither of which the stock Fiero ECM will understand.
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| Cavalier 2.2 module |
So looking at the wiring diagrams for the Fiero and the Cavalier a major difference that I found is in the ignition modules. The Fiero ignition module actually sets the base timing for the coils and a signal from the ECM varies the advance or retard. Whereas the Cavalier module is only there to fire the coils, it has no internal timing program. The Cavalier ECM sends a 12 volt signal to the module when it wants the coils to fire based obviously on many inputs. This is very similar to the way the LS series of coils works, only they are triggered by 5 volts not 12 volts (according to the Megasquirt web site). So my new problem that I have created for myself (in addition to many others) is how can I get a 12 volt signal to safely and reliably trigger a 5 volt coil. Or will the coils trigger off of a 12 volt signal and the megasquirt site is just using a more regulated signal. If I can get this new problem solved (and I do have the time to solve it) I will be able to mount four powerful coils on top of the valve cover. Granted the OE wasted spark system works great, I just think the LS coils have a higher cool factor. Plus I would have to remount the ignition module anyway, since the Fiero ignition module has the crank sensor bolted to the back of it then the assembly is bolted to the block down under the intake manifold (hard to change the wires). The cavalier uses a bolt in crank sensor and a remote mounted ignition module, so I could mount it where ever I so choose. So I figured why not complicate the issue and add something cool too? I really need to find someone that is good at electronics and building circuits. Hey, that's another problem. Just great.
