Temperature gauge mis-match

[Berty]

My Cosmo is currently giving me strange temperature readings. As some of you may be aware, the Cosmo has four probes. One in the rear iron which feeds the cluster. One in the back of the thermostat housing for the ECU and two after the thermostat, one of which is for the Auto ecu and other I'm not sure.

Long story short, the temp gauge on the cluster will jump to very hot every now and then, however the reading from the Microtech and the aftermarket Greddy sensor both read within spec (81 to 90 degrees C). The Microtech is taking it's reading from the sensor in the back of the thermostat (former ECU sensor) and the Greddy gets its signal from a sensor in the top radiator hose.

This has only just happened since unplugging the TWS. I've also re-burped the cooling system. Has anyone else had this happen? I'm thinking it is new TWS time as I believe that the dash cluster uses a resistor inside the TWS to create the voltage which feeds the temp gauge.

 

[rodneooo]

I believe the other sensor that your not sure of its a temp switch for the thermo (possibly a high speed setting for when things really heat up) not too sure as 13bs dont have it.

hmmmm tricky one. The factory temp guage on my car has randomly spiked up a couple of times on really hot days for no apparent reason and scared the s*** out of me. Nothing seemed out of the ordinary at the time. Engine wasnt overly hot. But it hasnt happened in about 2 years...
In those 2 iv changed, rad, guage sensor, thermostat, water temp sensor, cluster and added aftermarket temp guages.
Hasnt happened since.

how oftern is it doing it? under what conditions?

 

[Berty]

I would dismiss it if it were entirely random, however I believe that it may have something to do with the secondary injectors engaging.

After doing a bit of fiddling, I have a suspicion that the rear, secondary injector may not have been squirting. I'm going to take the rail off and see if the injector is any good. Good times.

 

[rodneooo]

thats no good!
I cant see how that relates to a temp reading though. esp on the factory guage which only moves up over half above 100.

 

[Berty]

Injectors came back - one is faulty and stuck open. Currently waiting on a response from the place where I got them to see what my options are.

Also ordered another aftermarket temp gauge which is more accurate than the factory gauge. I tried plugging the Greddy sensor into the rear iron but couldn't screw it in. Not because it didn't fit, but because Mazda love to put hard lines in the worst places.

 

[cosmojc]

A thread recently came up on the FD Forum. Faulty Temp sensor was causing all sorts of problems inluding idle (???). And we all know how much a Cosmo loves to mess with your mind over erratic idle problems! I think all of these sorts of components are reaching then end of their life - time for new ones or alternatives. Can you post the info on the alternative you installed please?

Kramer