96 XJ faulty temp guage ?

[Liftedtj]

Both sensors have been replaced one in thermostat housing and the one in the back of head.
New CSF radiator
New thermostat
New water pump
New hoses
System flushed
New clutch fan put in at beach in May.

Temp reads normal when first crank Jeep from sitting over night. But as soon as I hit the road it jumps up to 240. Which I don’t believe it is. So I changed the sensor in back of head. Didn’t change anything. These are my readings after driving for 45 mins straight.

198 at thermostat housing

176 on hot side of radiator

154 on the return side.

No signs really over heating besides the gauge on dash. Any suggestions ? before I run a auto meter gauge to check accuracy.

 

[grapehead]

Sending unit in the thermostat housing goes to ecu, back of the head sending unit goes to gauge. Got a scanner you can plug in and see what the ecu is reading?

 

[Jody Treadway]

Sending unit in the thermostat housing goes to ecu, back of the head sending unit goes to gauge. Got a scanner you can plug in and see what the ecu is reading?

This.
Also there are 2 different sending units for those. One for use with a temp gauge and one for an idiot light. The wrong one will cause this as well.
First you need to see what the PCM is seeing like Mr @grapehead said.

 

[Jeff B]

I have an equus gauge using that back port on the head and it always reads about 230* however my factory gauge reads 200*

this one.

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[Liftedtj]

Sending unit in the thermostat housing goes to ecu, back of the head sending unit goes to gauge. Got a scanner you can plug in and see what the ecu is reading?

Data from My live feed scanner on way home from work. 45 min drive. Highway then backroad.

 

[Caver Dave]

Data from My live feed scanner on way home from work. 45 min drive. Highway then backroad.

That indicates the ECM & dummy gauge are jiving, correct?
And that the 230* you're seeing potentially also correct?

 

[grapehead]

Maybe check for exhaust gases in coolant. Just for peace of mind. What condition/age is the coolant?

 

[Liftedtj]

Maybe check for exhaust gases in coolant. Just for peace of mind. What condition/age is the coolant?

just did a flush and went back with new coolant less than two weeks ago. Off today so went to check it out. Found this I’m sure it’s the head gasket