temp guage

[rochhound]

picked up a 88 b2 cracked head,replaced with 89 heads runs great.
my problem is the temp guage go's to hot when the motor is just barely warm.
i changed the sensor but still gives hot temp at guage?
could the guage in dash be bad?

 

[SolidSnake84]

picked up a 88 b2 cracked head,replaced with 89 heads runs great.
my problem is the temp guage go's to hot when the motor is just barely warm.
i changed the sensor but still gives hot temp at guage?
could the guage in dash be bad?

The in-dash gauge could be bad. The 80's model gauges are not very reliable due to the printed circuit boards on the back of them. The only way you can be sure is to install an aftermarket water temp gauge, like from jegs or autometer. That is your safest and most reliable option

 

[wildbill23c]

The temp gauge in my 84 B2 didn't work right, I ended up installing an aftermarket 3 gauge set (oil pressure/temp/voltage).

 

[enjr44]

My wilda** guess is that the gauge in your panel used a different sending unit than the one you installed. There are two types out there. One has more resistance when cold and drops with heat. The other has low resistance when cold and more as it warms.

You can test the gauge. With key in run, pull the wire off the sender. It will either go to hot or cold. Ground the wire, it should go completely the other way. If it does the gauge is working. If it doesn't change it also could be wiring.

 

[RonD]

And did you change the right "sensor", there are 2:
ECT(engine coolant temp) SENSOR, only used by the computer, has 2 wires
And
Coolant temp SENDER, only used by the dash board gauge, has 1 wire.

Do as enjr44 suggests, find the 1 wire SENDER and disconnect that 1 wire, turn on key and watch the temp gauge, needle should peg to COLD or HOT.
Ground that 1 wire(key still on), temp needle should peg to opposite COLD or HOT


ECT sensors were added with fuel injection, since there are no jets(no carburetor) a Choke plate can not work, so computer needs to know engine temp to adjust fuel mix richer when engine is cold, just like Choke plate did.