AndrewMAshton Posted September 18, 2020 Report Share Posted September 18, 2020 Hello, some of you may recall I fitted Efi to my 4a, this included an ECU which can be connected to a laptop enabling the user to monitor many aspects of the engines condition. My car has always run cool as per gauge, between 65 and 70 degrees C, only creeping above when stationary and soon brought back under control with the electric fan. I had to fit a second temp sensor to supply the ECU, today I took the car out with my son-in-law driving, me with lap top on knee, surprisingly, or not, there was a difference between gauge and ECU temperature of 15 degrees C with the gauge reading low, although consistently low. On a longish drive the engine, on the ECU settled at 70-71 degrees C which is the mid reading on the gauge, however searching the forum the ideal running temperature is 82 to 88 degrees C, is this correct? and if so how do I raise my engine running temperature and can I get my gauge to read more accurately. I use a solid state voltage regulator which is supplying 10V, thanks in advance, Andrew Quote Link to post Share on other sites
Andy Moltu Posted September 18, 2020 Report Share Posted September 18, 2020 Assuming the engine still has its thermostat fitted I would suspect that the stat is opening too early. Quote Link to post Share on other sites
Geko Posted September 18, 2020 Report Share Posted September 18, 2020 FWIW, onboard instruments aren't meant to be accurate but only providing a health check at-a-glance with needles floating "somewhere in the middle". Last thing you should expect from dash gauges is accuracy. Quote Link to post Share on other sites
RobH Posted September 18, 2020 Report Share Posted September 18, 2020 You can raise the engine temperature by fitting a thermostat with a higher opening temperature and Moss (for instance) offer a range of thermostats from 72 to 88 degrees. It is possible to adjust the reading of some types of electrical temperature meter and there was information on doing that in a recent(ish) thread. As a matter of interest where did you install the second temperature sensor? Quote Link to post Share on other sites
AndrewMAshton Posted September 18, 2020 Author Report Share Posted September 18, 2020 Rob, I had an aluminium boss welded onto the thermostat housing, above the original temp sensor, cheers, Andrew Quote Link to post Share on other sites
RobH Posted September 18, 2020 Report Share Posted September 18, 2020 (edited) Don't necessarily believe the reading from your EFI if it is using a normal gauge-type resistance sensor and wasn't calibrated with it. Those sensors are in no way calibrated themselves. You can only really rely on a separate meter like a thermocouple one to tell you the truth give-or-take a degree or so. I have found the gauge adjustment procedure (I think this is of US origin so ignore the last bit) : Edited September 18, 2020 by RobH Quote Link to post Share on other sites
PodOne Posted September 18, 2020 Report Share Posted September 18, 2020 Hi Andrew As long as your AFR's are reasonable once she is up to a stable temperature I wouldn't worry unless your seeing over 90-100c. Out of interest is the EFI temp sender on the hot or cold side of the radiator as that will make a bit of a difference. Best location is the hot end of the head usually at the back of number 4 cylinder. Will the ECU allow you to calibrate "zero" the coolant sender so you get a more accurate readings as some ECU's will allow you to get better fuelling. Some will allow the same for a separate inlet temp data to contribute to the fuelling table/MAP. As said if your happy with the AFR's I would give her some welly and enjoy. Probably more important the oil is getting to the right temp. Andy Quote Link to post Share on other sites
AndrewMAshton Posted September 21, 2020 Author Report Share Posted September 21, 2020 Hell All, thanks for the responses, I will fit a hotter thermostat as I understand ideal temperature is in the mid 80's, I got that from a previous post on the forum. The sensor is on the hot side of the radiator if I understand the question, it is placed so the coolant exiting the engine passes over it, I think, I have yet to strip a TR engine down. Would a better place for the sensor be in place of the drain valve on the side of the block? I need to study the ECU manual a little more to understand what calibration is available, cheers, Andrew Quote Link to post Share on other sites
Waldi Posted September 21, 2020 Report Share Posted September 21, 2020 If you install the sensor in the bottom of the radiator (where the coolant has cooled down) you do not control engine temperature properly. It is ok to have a electric fan switch in the return pipe though. In that case the water temperature can still be measured at the top and the engine coolant temperature can be monitored. Waldi Quote Link to post Share on other sites
PodOne Posted September 21, 2020 Report Share Posted September 21, 2020 Cylinder head is the best place for the sensor. Andy Quote Link to post Share on other sites
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