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Old 02-18-2010, 05:45 PM
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coolant sensor for gauge and ECM?

Can I use the coolant temp sensor (the one currently used for the temp gauge) for the coolant temp input of a TBI computer? If so, can I connect both wires (one to the gauge and one to the ECM) to the one sensor?

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Old 02-19-2010, 12:26 AM
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it is possible to use the temp sender for the gage as the temp input to the ECM only IF the sender is calibrated the same as the the one made for the computer.
but i would very strongly suggest not doing it it will only caause you headaches.
coolant temp is a major input for fuel calculations, especially when cold.
also, most temp sending units for use with the gage are only a 1 wire hookup and are grounded thru the body of the sending unit.
the ones for use with the ECM are not ground thru the body, they are a 2 wire hookup with the second wire being the ground for the sensor.

no, you can not use the same coolant sensor for both the ECM and gage. you would have 2 input voltages that may be the same, but will shift the values seen by both the gage and ECM.
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Old 02-19-2010, 07:58 AM
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There's a reason why GM used two different sensors on their computer controlled cars, and it wasn't just to increase production costs.
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Old 02-20-2010, 08:25 AM
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A couple of suggestions:

Most aftermarket manifolds have one or two pipe-threaded holes in the top, and you can remove the plug and replace it with a sender.

On an SBC block there is another tapped hole on the opposite side of the block from where the OEM temp sender goes. Just remove the plug on that side and replace it with your additional sender.

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Old 02-21-2010, 12:21 AM
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oval shaped plug CTS in the front of the intake by the thermo housing is for the ECM
two wires to it,

it helps determine fuel mixture

the temp sensor in the cylinder head is for the temp guage

single wire, usually dark green,

these two parts are completely different form each other and cannot be role reversed or swapped.

ppl seem to have a hard time with this simple concept for some reason..

the CTS ohms resistance will be around 12k at around the freezing mark, if its good.

there is a complete chart out there somewhere on the net with all the temperatures and proper resistance readings for these common GM CTS's

if it is bad and is telling the ECM the engine is colder than it actually is then it will help worsen fuel mileage/economy

the CTS is for the ECM only

and the sensor is for the guage only

good luck!
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