Water Temp Sensor
Thread Starter
Drifting
Joined: Aug 2002
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From: Speedo Indiana
Water Temp Sensor
Does anyone know how the signal gets from the water temp sensor to the instrument cluster gauge? I know the 5 volt supply comes from the ECU.... but what makes the gauge move? I have been through my service manual several times and cannot find anything... of course I don't have the electrical supplement yet...
Race Director
Joined: Sep 2000
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From: The Top of Utah
Re: Water Temp Sensor (TONYDEE64)
You have an ECU on a 1964??? The L83 and L98s have a temp sender in the front of the intake that the ECM uses. There is a hole in both (they're the same either side) head, between the #1 & #3 plug on the left, which puts it between #6 & #8 on the right side. Depending on the year, one head holds the temperature gauge sending unit, and the other has a temp switch for the fan or aux fan, if so equipped. If you can tell us what your working on, we may be able to be more specific.
RACE ON!!!
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Thread Starter
Drifting
Joined: Aug 2002
Posts: 1,475
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From: Speedo Indiana
Re: Water Temp Sensor (CFI-EFI)
No, I was born in '64. Car is a 1991. The reference to the twin turbos is kind of a running joke. My car actually has a Procharged Big BLock... See the C4 Forced Induction forum for pictures...I bought this car in pieces so I just have no idea how the electrical current actually makes it to the gauges... In other words.. I see the 5 volt reference coming from the ECU... but I do not see a signal out going to the gauge... Somehow the ECU sees a resistance from the sensor based upon the temp at the sensor... but then what happens?
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Re: Water Temp Sensor (TONYDEE64)
No, I was born in '64. Car is a 1991.
I bought this car in pieces so I just have no idea how the electrical current actually makes it to the gauges... In other words.. I see the 5 volt reference coming from the ECU... but I do not see a signal out going to the gauge... Somehow the ECU sees a resistance from the sensor based upon the temp at the sensor... but then what happens?
Does anyone know how the signal gets from the water temp sensor to the instrument cluster gauge?
RACE ON!!!
Thread Starter
Drifting
Joined: Aug 2002
Posts: 1,475
Likes: 0
From: Speedo Indiana
Re: Water Temp Sensor (CFI-EFI)
Thanks for your reply.. Maybe I should elaborate a bit... I run my motor with a FAST computer... The temp sensor is feeding the correct signal to the laptop... Of course I had to disconnect the factory wire at the ECU since it would also be sending 5 volts to the sensor (the FAST and factory ECUs cannot share a sensor). So.. of course my water temp gauge did not work. I disconnected the FAST ecu wires and hooked the factory wires back as original... and to my surprise the gauge still doesn't work... neither does my oil temp gauge although I've run the diagnostics on both sensors and they are fine. If I ground the oil temp sensor wires I can make the oil temp gauge go all the way to the right...so the wires are hooked up the gauge of at least the oil temp gauge. No matter what I do the water temp gauge I can't make it do anything...
