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Semi-related and coincidental from my earlier posts, but I have a 216 which at some point has had a 1.4 engine and ecu fiited, turns out the 1.4 ecu didn't control the engine fan as the 1.6 ecu would have done (probably relied on a rad bi-metalic switch instead), so they had fitted a manual dash switch instead.
I wasn't really keen on this so looked to make the fan control automatic again, I had a look inside the ecu and there is a nice space where the fan control should be, so I decided to knock up a basic circuit to fit inside the ecu and control the fan just as the standard circuit should do. The rest of the circuit was still in the car, relay wiring etc.
I've taken a feed from the coolant temperature sensor, does a nice job, fan comes on about 86 degrees, goes off again at about 82, keeps the temp guage just below middle.
First pic is during testing / tweaking.
Once I'd established it worked, I tidied it up a little and set it in hot-melt glue.
I've left the manual switch connected as well, just in case.
Similar circuit would operate any fan with a suitable sensor and a couple of extra components (I tapped into the ecu's regulated 5v supply, would need to add that on a stand-alone unit).
I wasn't really keen on this so looked to make the fan control automatic again, I had a look inside the ecu and there is a nice space where the fan control should be, so I decided to knock up a basic circuit to fit inside the ecu and control the fan just as the standard circuit should do. The rest of the circuit was still in the car, relay wiring etc.
I've taken a feed from the coolant temperature sensor, does a nice job, fan comes on about 86 degrees, goes off again at about 82, keeps the temp guage just below middle.
First pic is during testing / tweaking.
Once I'd established it worked, I tidied it up a little and set it in hot-melt glue.
I've left the manual switch connected as well, just in case.
Similar circuit would operate any fan with a suitable sensor and a couple of extra components (I tapped into the ecu's regulated 5v supply, would need to add that on a stand-alone unit).
I think the idea to use the existing temp sensor is a good one and what I will be doing unfortunatley at the moment my temp gauge has stopped working not sure if its the sensor or the wiring or the guage I will have to diagnose that shortly. To get the right amount of hysteresis I could just set the comparator circuit up with a fixed point or probably more sensible but maybe not worth the trouble put a sensor part way up the radiator or at the bottom though with this approacch I may just be making a rod for my own back with little to no improvement in performance as people say (me ) simple is best.