I’m planning to relocate coolant temp sensors on a V12 and I would like to know your thoughts about new locations I chose:
Coolant temp gauge sensor - move to left side in place of ecu temp sensor.
ECU coolant temp sensor - I’m planing to move it to right side water rail, but also to the back of the engine rather then next to the thermostat. I believe that this location will have a more constant readings for ecu as current location next to thermostat might give sudden temp fluctuations when thermostat starts to open and cool coolant starts flowing in.
I doubt it’ll make any significant difference to how the engine runs - or any difference at all to be honest.
If you want to see a graph of how quickly the temperature change as the thermostat opens and closes then look for a previous post of mine for the graph. The ECU mapping of how much to weaken the mixture as it goes from ~75’c to 85’c will likely show a percentage change of no more than ~2% and thereafter, the thermostat is only ever adjusting itself after a time lag reflecting how long it takres for water to come back from the radiator, by which time the load on the engine will have changed and the adjustment will have been adjusted again.
The idea in the begining was to move gauge sensor to left side which usually has overheating problems as per recommendations in the XJS Help Book. Then the ecu sensor had to go somewhere else so that’s why I chose to move it to right side. Here is a picture of repositioned sensor and stainless steel water rail pipe.
FYI, your EFI may use coolant temperature for warmup only. Above a certain coolant temperature, it may only use air temperature for control inputs.
Chandler
78 XJ12L, 83 XJS MS1 EFI
