So i just bought my childhood dream car, a 93 CB7 and also my second Honda. My other is and 06 Odyssey. I took the car in for an emissions test. the girl conducting the test did something to my car. coolant shot out the overflow all over the right side of the engine bay. on the drive home my TEMP gauge started dropping. there is nothing wrong with the car but the gauge is dead in the water. Does anyone have any clues?

 

First time I heard of a temp gauge going down. Did it overheat after the test? White smoke under the hood?

 

No not at all. Simply dropped as if the temp was going down...then rested on the bottom like the car was off. I was just like a movie scene.

 

Anyone this is interesting stuff???

 

Coolant can leak past a faulty or busted coolant temp sensor.If the sensor disintegrates and it has now continuity thru the circuit it will drop to nothing just like you disconnected it.Find the coolant leak,fix then go from there.I believe the sensor is under the dizzy in the head.Goodluck

 

So I caught it today. on my lunch hour the gauge was working. when i fired her up to drive home for the day, nothing. Is it possible its just a short?

 

Yes,But the engine coolant temperature sending unit signal would have to be open either in the sensor or between the sensor and cluster.Disconnect the sensor and see if the gauge remains at the bottom.If it does than jump the the two wires with a fused jumper or a paper clip.The gauge should now be pegged at the top of the cluster.If that happens i am 97% sure it is the ect sending unit Because that sensor takes a certain voltage and it runs thru the sensor and as temperature increase so does resistance changing the output voltage to the cluster gauge.Goodlick.

 

Thats what i was going to say, sounds like the sensor took a ****.

 

Thanks guys...ill be doing that this weekend.

 

I thought a 93 had the one wire sensor on the end of the head that drove the temp gauge.....

Single wire off, no reading on gauge. If you ground the single wire the gauge should go up.....do not peg the gauge doing this test as that will damage the gauge.

 

I apologize for any confusion in my post.But you have a sensor for the fans,a sensor for the ecu/cluster,and we come to the one you are talking about and that one is a switch i believe for a coolant light for over heating.That only has one wire so you know it is a switch.It has to have more than one wire to be a sensor.It will not damage the gauge if you only jump it quickly.You need to have the key off engine off first,disconnect the sensor,jump it the turn the key on inside while observing the gauge.If you have any difficulties you can hit me up will your email and i will send you a factory service manual in a pdf form if you like.Peace and good luck

 

Sensor for the fans-thermo A and then there is thrmo B. Sensor for the ECU- ECT-two wire, again on the end of the head under dist. Temp sending unit/sensor (haven't seen a LIGHT on an Accord?), single wire sensor that varies resistance to ground as the sensor/engine heats up....you go against yourself in your post....is it a switch or a sensor?

 

I always go against myself,but not on purpose but because i have super ADHA.No excuse though.It is actually referred to as a sending unit.Which makes it a potentiometer.I only want to help not mislead and that is always my intentions.I opened up the PDF finally instead of trying to rely on my brain.This is the Gauge test..#1 Check the #8(10a) fuse in the under-dash fuse/relay box and YELLOW wire between the under-dash relay/fuse box and the gauge before testing.#2 Make sure the ignition switch is OFF,then disconnect the RED wire from the engine coolant temperature(ect) sending unit and ground it with a jumper wire.#3Turn the ignition on.Check that the pointer of the ECT gauge starts moving toward the red zone.Caution!!!!!!!! Turn the ignition switch off before the pointer reaches the red zone on the gauge dial.FAILURE to do so may damage the gauge.>>>>>>>If the pointer of the gauge does not swing at all,check for an open in the RED wire.If the wire is ok check the ECT gauge>>>>>>>>>If the gauge is OK,Check the ECT sending unit.Now as for the sending unit test itself.It is.#1 Disconnect the red wire from ECT sending unit.#2 With the engine cold,use an dmm set to ohms to measure resistance between the positive terminal and the engine(ground).#3 Check the temperature of the coolant.#4 Run the engine and measure the change in resistance with the engine at operating temperature(Radiator fan comes on)#5 If the readings you get are substantially different from the specifications,replace the ECT sending unit........>>>>>>>>SPECS ARE AT 133F 142 oHMS,AT 185F-212F 32-49oHMS. Like i said i only want to help,i am unemployed now and have been for about 6 months.I have spent the last 15 years working on cars.Goodluck

 

Hey, didn't mean to sound like an a**.

OP see if this helps...froma 91 but should be close to the 93.

 

That is where i quoted the above.I haven't figured out how to copy and paste from a pdf.If i try to add an image in ask for the url and i have no idea how to find in,even when i go to the properties of the document.I guess somethings are meant to be above me.Peace

 

That is awesome thanks.