Leaderboard

As well as retarding the ignition for a cold engine, the temperature is used to apply choke, and turn on the manifold heater. So it's pretty important.

I have the luxury of a copy of the Haynes Service and Repair manual .... I found a copy on line some time ago... I am rebuilding using the original Sierra Gia model loom that had ALL the bells and whistles. I don't need most of the wire, but I am too cheap to just throw it away and buy a new purpose built loom. So I have been pruning literally pounds of weight out of the mass of wires, and in doing so have had to take care not to remove something I need. So to get to your questions. The manual says the Power Hold relay allows the stepper motor (it's what operates the choke) to operate for a short time after the ignition has been turned off, to ventilate the manifold and deter the engine from "running on". Running on is what it says, you turn off the ignition but the engine keeps running for a while, very annoying. As for your temperature guage question. There are two temperature sensors shown in the manual, I did not look on my engine because it's all wrapped in cling film at the moment. In Chapter 3, page 3.8 picture 16.3a shows a sensor screwed into the block just opposite the dizzy cap. This is the one that runs to the guage, in the wiring diagram it is item 30 "Coolant Temp Sensor". The other sensor, the one for the ESC module is item 58 "Engine Coolant Temp. Sensor" its located in the underside of the inlet maniford (Page 5.20, picture 19.4) it's a bigish plug just above the oil filter.