Spark dropout under load, then dies

[TwinScrew20v]

Hey guys, Ive got a VW VR6 that I recently changed the coil on and now I'm having some serious spark issues. I replaced the OEM coil packs driven off of the Bosch ignition drivers for 3 MSD 8224's. I initially tried these coils (no programming changes, just a swap in) a couple of years ago and had ECU resets and pulled them because I needed the car running. Now I've reinstalled them and made adjustments to the dwell settings. MSD suggests a 2.4-2.5ms dwell on these coils, but even as low as 2.0ms I get spark dropout. It starts at high rev load and gradually (or quickly if youre in it and it starts dropping out) and then dies and will restart after 15 minutes, albeit a hard start. I'm assuming this means the coils are overheating (or the drivers?) but they are barely warm to the touch. I didnt have any of these issues with the VW coil packs and theyre pretty poor for spark so I'd like to get this sorted. I do see the AF bounce back and forth between extremely lean and extremely rich under this load in the log, and I'm not sure if that is due to the spark cut. I dont see this on my wideband however.

Anyone have any ideas? When it does run its WAY smoother than the OEM coilpacks. Thanks for your help guys.

[Matt Cramer]

The misfires may be your acceleration enrichment; try raising the MAPDot threshold.

[TwinScrew20v]

I apologize for writing a hasty post late last night, but it looks like I left out the part where it begins at high RPM and then gradually starts dropping out earlier and earlier. Would the MAPDot threshold still make sense then? I recently put a turbo back on this motor and I changed back to speed density (which had poor accel enrich settings anyway) so I turned up the MAPDot to retune the VE table and actually I've been running it for about two weeks prior to swapping the coils. I'm all for trying it when I get home tonight.

I also realized I'm running 3 VB921's on this car. I used the BIP's for the MS3 ECU I built for another setup. Not sure if that makes a difference in how the coils function...

Thanks again.

[cwdodson88]

Would dwell cause this? almost sounds like the coil overheats under heavy load, then as load decreases it continues to miss a spark.