Electrical fault

Hello,
Just purchased an MGTF, 2004. The chap who sold it to me has described a starting problem where the engine fires up and dies almost immediately. When the wires are removed from the temperature sensor the engine starts and runs fine. He has changed the sensor but the problem still persists. I would appreciate any advice and apologise in advance if this has been covered before.
Cheers
Ken

From what I've learnt there are two sensors Blue connected to the gauge, Brown connected to the ECU, is it perhaps the ECU sensor was mistakenly changed for a gauge one and has upset the ECU. I would check both sensors to find out if they are the correct ones. I don't know there exact location but if you google it you should be able to find there location.

Thanks for this, I'll check this out.

Located back left of the engine (ie close to the passenger firewall). The blue one is the most difficult one to get out as hidden by the water pipes. Access is via the top below the parcel shelf. The ECU (brown) one easy to change.

The brown one will be the one of interest and the blue may safely be ignored. It looks as though it may be short circuit. Plug another one in without changing the one in the engine. If all is well, waggle the cable near to the sensor. If the engine misbehaves, the fault is in the wiring near to the plug and if not, then change the sensor.

The ECU coolant temp sensor (CTS) has a 2 pin plug.

The gauge CTS has one. If this sensor is shorted either the dash gauge will not read or will go to the top.

Thanks again for all the tips. The million dollar question might be, where do I get new sensors and what codes do I use? Please keep the tips coming. I'll be collecting the car in the not too distant future, hopefully. Once I clear a space in the garage.
Ken