Right, I have an issue with my car over fueling and running rough so I wanted to test a few things before taking it somewhere. I have a mk2 escort with a 2wd cosworth turbo engine

I disconnected the coolant temp sensor and checked its resistance cold and it's about 4.5k ohms which sounds about right. I checked voltage to it at it was 4.3v. I decided this was correct so plugged back in and now I can't start it at all??!!

I have tested back at the ecu plug between pins 11 and 29 which are the 2 from the sensor and I have 4.5k ohms so it is connected right. I haven't touched anything else, I have tried reconnecting other plugs still nothing. I have a spark and I have fuel pressure but it just doesn't fire!

I did try starting the car with the temp sensor disconnected and it wouldn't start. Could the ecu have gone into some sort of lock mode because of this as I literally drove the car out of the garage, messed with the one sensor and now it won't start at all.

Any ideas?

Thank you