[Ed Wright]

I use an MSD 2 step on mine with the FAST XFI ECU, no problems. It has nothing to do with the injectors, the MSD kills the spark. I had one customer having problems with that but he had his MSD grounded to the battery along with his XFI ECU. Don't do that, ground the MSD to the engine. Not the floor pan, roll cage, battery, etc. Directly to the engine. If your pushing fuel past the rings you much be over-fueling it. Don't do your launch air/fuel tuning from your wideband, if you can't do it on an engine dyno without the 2 step (I've never had mine on an engine dyno), go by your 60' times. The miss-firing while on the 2 step will make it look very lean to your wideband, you can end up leaving very rich. My wideband doesn't read correctly until nearly 6000 RPM on the launch. Just another reason they typically run quicker in open loop. It would be trying to fatten up a false lean condition. If your trying to run it in closed loop, be sure to set your minimum closed loop enable RPM well above your launch RPM. I picked up over a tenth just by putting mine back into full time open loop.