Ok well I have an interesting problem on my 91 acord EX. Besides the fact that my cooling fans dont come on at all, my temperature guage is constantly stuck at 40-50%. It doesnt matter how long the car is sitting for the temp gauge is always stuck there whether the key is in the ignition or not, I even unclipped the whole gauge cluster from the harness and its still stuck there and all wires look fine. From what I understand to test the guage you disconnect the single wire on my car its red from the coolant temp sending unit on the head and ground it to metal. I did that with key on and the guage stayed where it was it didnt start moving to to the red which it should have from what Ive researched. So the guage is bad??? how do I go out changing the guage or do I need anew guage cluster. Also I read on a post about a 98 accord that the coolant temp sending unit should measure a resistance of 142 when the engine is cold. Im not sure if this is the same for my 91 but I was getting resistance readings from 60 to 95 cold. Does that mean the sensors bad too or what is the proper resistance for my year accord?


Oh and what is the purpose of the Enigine coolant temperature sensor right next to the temp sending unit because I noticed on my car the wires need to be respliced would this affect anything with the guage or fans or what is this sensor for??

 

This is what I did but the post was from a 98 so not sure if the readings should be the same.

 

well my haynes dosent specify the resistance but the sensor for the temp gauge is the small one under the dizzy and the one for the fans is on the t-stat housing. I dont know which sensor your checking though as the one in the pic

 

I was checking the temp sending unit on the head under the distributor and the resistance seemed way off from the picture I showed but that was a 98 so Im not sure if tis the same.
Also when grounding the connector that slips on the sending unit the needle on the guage didnt move, leading me to believe the actual guage is also bad.

Also the other sensor thats right behind the temp sending unit, also on the head and under the distributor. whats its purpose?? it is a green connector w/ a blue and black wire coming from it???

 

bump

 

this is the ECT sensor that reads coolant temp to the ECU

 

Ok, Im curious what does the ECU do with the readings, does it simply see if the temps too high the ECU turns on an idiot light or does it take that temp reading and do more with that?

 

the CEL not come on for overheating. the ecu makes adjustments to fuel and timing maps based on coolant temp. if the ECT sensor is not functioning properly or unplugged, you will get a CEL

 

I've got a 98 accord that the guage works when it wants to. not sure if the burned up fan is the culprit.

 

can you give more details? are you saying the gauge gives false readings or doesn't register at all? sounds like you should check the wiring running to 1-wire temp sensor under the dizzy. see pic in post #2

 

Anything under the Distributor is completely covered in road filth/engine oil wonder if it could cause something to not work.

What I mean to say is that it only works when it wants to... most of the time it sits at dead cold and will flicker up to where it would be at running temp then kicks it self back down to dead cold. It makes me think there's a loose connection somewhere.

On a side note my check engine light doesn't work either.... if I smack the dash real hard while the car is running the check engine light with either come on and flicker or come on and go out as soon as I hit the dash. It also doesn't light up when the car does its preliminary checks when you turn the key to the on position.... I swear this car is possessed.

 

^^ no dude your car just hates you hehehe.. you probobly need to change out the Cel bulb.
To Ace398: it's probably the temp gauge itself thats bad because when you unplugged the Cluster, it should of when down no matter what.

 

Alright well got the problem fixed, I put a new gauge in it and it works perfect, didnt need the sending unit. Did come up with another problem though. When I took out the temp and fuel gauge the original fuel gauge in my car was 3/4 full. The new guage I put in was on 1/4. I put it in and with ignition on the fuel gauge climbed all the way up to above F, so w/ the car off, I pushed the needle to E and as soon as I turned the car on it climbed up to above F again. Is there a way to reset the guage?, I figured pushing it all the way down would reset it??

Im thinking about filling the tank up and seeing if the gauge comes down as i drive around.

 

You could try that, I was always told if you change the fuel gauge to make sure that you install the new one with the needle in the exact same spot as the old one.

 

well even if I had installed the new one with the needle in the exact same spot it still would have started climbing when I powered on because it was at 1/4 when I first put it in and it climbed all the way up to full, and I tried putting it where the original needle was at and it still climbed to full. So then I pushed it down to E and it climbed all the way up to above F. I did fill up the tank now and the needle hasnt moved and Ive driven around 80 miles

 

I don't know what the fuss is about because now you'll never have to fill up your tank again hahha...First: try to take and re-install the gauges. Second: If you still have your old Temp/Gas gauge laying around try re installing it and see if the gas gauge works. If it does then you'll probably going to need to get another new temp/gas gauge

 

I had a similar issue with my 91 Accord. Even when the coolant had started to boil over, the temp gauge read normal. I purchased a new sensor, part 37750-PH2-014. Out of curiosity, I heated the new sensor in a beaker full of water and measured the change in resistance as the water heated up. Surprisingly, the resistance I measured did NOT match what is listed on page 16-128 of the manual. The manual lists resistances of 142 ohms and 49-32 ohms for temperatures of 56 C and 85-100 C respectively. At 58 C, I measured 208 ohms and at 85 C: 80 ohms. Significantly higher in both cases. I even measured my old, suspected faulty sensor and got only slightly higher resistances. It seems unlikely to me that the new sensor is bad and that even the old one may not have been "that" off. Using the measured data, I extrapolated using the Stanley-Hart equation for a thermistor to solve for the expected resistance at 100 C and got 49 ohms, 17 above what the manual says. At 130 C, I got 28 ohms. Finally, I connected varying fixed value resistors directly to where the sensor would normally connect. The lowest resistor I had on hand was 22 ohms and that got the temp gauge needle barely below where the "N" is on the shifter indication on the opposite side. 22 ohms corresponds to 145 C using the equation. That's almost 300 F! This means when I notice what appears to be a small rise on the gauge, my coolant might be boiling away! I am not sure if this is an issue with a defective new sensor, bad coolant gauge or both. The only advice I can give is to closely monitor the gauge and know what ACTUAL temperature corresponds to where the needle is pointing.