'91 300CE - W124 M104 - Cranks but no start

[rgnprof]

I used my '91 300CE to jump start my '72 250 - no problems initially, got my old car started, but when I went to back up the 300CE, it stalled and I haven't been able to get it started since. I've had ongoing problems with warm starts, but not like this, usually I can get it to start after some cranking - but this time it hasn't even tried to turn over once...

I changed out the OVP (with an old one that I had replaced a while back), fuel pumps are running and I can smell some gas, but it doesn't smell flooded. I haven't yet checked for any spark with the ignition...can someone outline the best way to do that on this car?

Thanks - any help appreciated.

ryan