2-Group with no water-temp input

[Forg]

How poorly will an ECU, specifically a 2-Group 3D (gold box) run without a water temp sensor attached?

Doing some testing with a used head; the heads for my car that're cheapest & most available don't have the water-temp sensor hole that the heads on the later-build engines have; so I'm considering running 'round for maybe ~500km without a water temp sensor.

Will it just completely fail? Will cold-start just be a bit dodgy?

[RossB]

It will not hurt the ECU in any way, it is just going to be difficult to start and run poorly when it is cold.