77 280SE Won't Start
Sounds like you are on the right track. However, did it run before they "steam cleaned" the engine ?
This problems sound very similar to the problem I am having with my 71 250CE. Which injection system does this have ? DJetronic or Kjetronic ? If you have adequate spark, and fuel and it's still not firing, then that sounds pretty strange. Did you make sure the timing is on? I once had a 4.5 280SE that someone had loosened the distributor on and accidently turned it around, it was getting spark alright just in the wrong order !
You are on the right track using Bosch or NGK plugs, I once bought a 280SE 4.5 because the owner was told the ECU was bad and it was going to cost her $2000 to fix it. In the end someone had put champion plugs in the car! $18 worth the plug solved a $2000 problem.
Make sure your Ignition control unit didn't get blasted also. It's a square box with fins on it. Usually under the battery or mounted to the firewall near the coil.
Also try changing your gas filters, perhaps somehow water found it's way into your fuel system. Does the pump run when you turn the key on? It should pump for like two seconds then stop.
125PSI sounds terribly low for this engine. My 250CE runs around 165PSI or so and I think the minimum was 145psi. You might want to check into that.
Remove your cold start valve and make sure it's only spraying for a few seconds when the car is first cranked and not continuously.
Start checking cold start components like the temp feelers, thermo time switch etc.
Contact me off board and I might be able to help a bit.
Starts but runs super rich