Using MS for spark only. Problem???

pete · Post by **pete** » Sun Jul 30, 2006 10:18 pm

As the subject says. I'm planning on using a V2.2 MSnS to run an EDIS-8 ignition on a carbed Mustang. I'm not quite ready to move to EFI yet and I needed to convert to EDIS due to clearence issues with the manifold I intend to run. The board mods have already been done to support EDIS using LED 17 for SAW.

I know the guidance is to start with fuel only but I need to know if there will be any issues with running MS without fuel. I only plan on hooking up the MAP sensor.

Another thing I found is there was a mistake, at least with the coils I'm using, in the wiring digrams. My coils came from an Explorer and were labeled with cylinder numbers. These just so happened to match my firing order. I wired the coils (low voltage side) as per the diagrams which turned out to be backwards. I guess it is not an error but it is advisable to make sure you understand which wire is firing which pair of plugs. It's pretty simple the firing leads are on the outside of the plug and correspond to the outside of the coils. I had a big backfire as I had the wires hooked up to the wrong side of the coils.

pete · Post by **pete** » Sat Aug 05, 2006 6:23 pm

Ok well so far it is working fine. Got it fired up and running in spark only. I was concerned about the injector duty cycle going way high so I set the rev limiter to cut fuel at over 250 RPM. This has the injector circuits shut down completely. Now I need to dress up the plug wires and start building my spark map.

I'm using and EDIS8 module off an Explorer and find that it does not work with multispark. Other than that it all works as expected following the instructions from here
http://megasquirt.sourceforge.net/extra/index.html

PSIG · Post by **PSIG** » Sat Aug 05, 2006 10:17 pm

MS is fine spark only. The wiring diagrams appear to be correct for EDIS8 on the MSnSE pages if looking into the wire harness - not the coils. AFAIK only later EDIS4 are capable of multi-spark discharge. Since EDIS8 can't do this, there has been an effort to allow the running of two EDIS4 on a V8 for higher rpms and possibly multispark, which I hope to try sometime.

David