temp gauge tops out, car not overheating, new sender
 

1994 honda accord

hey i just started using this forum but ive been on a few other ones.
my problem is that 99% of the time my temperature gauge in the dash says that my cars overheating. it goes to the very top of the red.. my car is not actually overheating.
first i replaced the sender, no luck.
then i replaced the thermostat, still nothing.
i took out the cluster and made sure everything was plugged in and it was. no loose wires or anything visible.
ive bled the cooling system a few times.
every once and a while the gauge will read properly but when i park and turn the car off/on itll read overheating.

Even if i let the car sit overnight, as soon as i start it it reads over heating.
is there any possibility that it could be the gauge? ive heard they get damaged if they ever max out hot...

any advice is appreciated.

Re: temp gauge tops out, car not overheating, new sender
 

The lower resistance the higher the gauge reads. Since you have a new sender, you may want to look for a short to ground between the sender and the gauge. Measure the resistance from the sender to ground, then from the gauge to ground; it should be the same.

Re: temp gauge tops out, car not overheating, new sender
 

Do you know where te ground is located?

Re: temp gauge tops out, car not overheating, new sender
 

I don't know where it's grounding out if that's the problem.

The sender provides the gauge with a variable resistance to ground. The FSM shows:

• 142Ω @133F
• 49Ω - 32Ω @185F - 212F

So, the lower the resistance, the higher the gauge goes. Since your gauge is maxing out, it may be that there's a short to ground somewhere between the sender and the gauge. A short to ground would make the gauge peg to the hot end.

Unplug the red sender wire from the sender. Measure the resistance between the unplugged sender terminal and engine ground. Then measure the resistance between the unplugged sender wire connector and engine ground.

Re: temp gauge tops out, car not overheating, new sender
 

http://www.youtube.com/watch?v=u5kjvh76qWk

i also re wired from the temp gauge in the dashboard to the sender. Does that eliminate the wiring as a problem?

Thanks

Re: temp gauge tops out, car not overheating, new sender
 

Do you have a digital volt meter?

Looking at the wiring diagram, the gauge has three inputs:

• Battery voltage on a yellow wire from 10-amp fuse #1 in the left kick panel; this powers the speedometer, tachometer, fuel gauge and cruise control indicator too
• Battery ground on a black wire from a point below the center console; this is the ground for the speedometer and tach too
• Variable resistance to ground on a yellow/green wire from the engine coolant temperature sending unit

Easy things first:

• Check that there's battery voltage at the gauge
• Check that there's battery ground at the gauge

Since the speedo and tach use the same power and ground as the temp gauge, and assuming those two other gauges work, any problem with the power or ground would have to be right at the temp gauge. If those check out, then the problem is with either the sending unit or the wiring between the sending unit and the gauge, or the gauge itself. Was any teflon tape or pipe sealant used on the sender? If so, that could cause an intermittent bad ground. A DVM connected between the sensor post and the block (ground) would show resistance in ohms for the sender, and that resistance should be similar to the factory specs, above.

Re: temp gauge tops out, car not overheating, new sender
 

Thanks I'll get a dmm ASAP. I was also wondering would a gauge cluster from a 94-97 accord without ABS work with my car?(has abs) not worried about not having an abs light.

Re: temp gauge tops out, car not overheating, new sender
 

Hey I bought a dmm today. Gonna use it after work I'll post the results. Also when I test should I have the car warmed up?

Re: temp gauge tops out, car not overheating, new sender
 

Just to check voltage, it doesn't matter if the car is hot or cold. It does matter to check resistance; use the factory specs above to determine if the sender resistance is in range.Was the problem the same before the rewiring?

Re: temp gauge tops out, car not overheating, new sender
 

thats your gauge

Re: temp gauge tops out, car not overheating, new sender
 

Roader- no, I re wired the sender wire after the problem started. To see if it was the wiring.

Jdm- I know. That statement was separate from the video.

Re: temp gauge tops out, car not overheating, new sender
 

Okay here are my results:

Wire @ sender to wire @ gauge in dash = 0 resistance (meaning wiring is good?)

Sender wire at the gauge reads 45 when car is warmed up (or just about warmed up)

This part confuses me: when everything was completely plugged in and car was warmed up but not running i got a reading of 38 (like you said) but then when i turned the key to the ON position i wouldnt be able to get a reading anymore....?? (gauge broken?)
please watch the attached video to see what i mean:
http://www.youtube.com/watch?v=eYGuR9NKzlk

Re: temp gauge tops out, car not overheating, new sender
 

its your gauge. either find a way to open it and transfer another one to it . or replace the whole cluster.

Re: temp gauge tops out, car not overheating, new sender
 

Thanks I appreciate it

Re: temp gauge tops out, car not overheating, new sender
 

It looks like the resistance to ground is infinite when you turn the key on, if I'm interpreting your meter correctly.

Check for battery voltage and ground at the meter. If they're good, I think JDM nailed it; you have a bad gauge. There's a coil in the gauge that could be opening when gauge is powered.

Re: temp gauge tops out, car not overheating, new sender
 

yeah thats why im saying the gauge it has a coil and if that coil is wrong it will top it self out due to it being bad. what you should do is open the cluster and smell the gauge and if it has a burn smell to it thats what it is. ive seen this on gas gauge on my 91 accord and it ended up being the gauge. it did the same thing. it will top out saying it was full. it didnt do it all the time tho. and it did have a slight burnt smell to it

Re: temp gauge tops out, car not overheating, new sender
 

alright well i bought a gauge today on ebay just have to wait for it... ill update once i get it.

Re: temp gauge tops out, car not overheating, new sender
 

Got the gauge! at first they sent me the wrong one (#0187) but i was able to exchange it for free and get the right part #0186 and it works now! Everythings back to normal. Thanks to Group.iwerks for the parts.

Re: temp gauge tops out, car not overheating, new sender
 

I know this is an old thread but I have the same problem and I think I caused it. I was doing the speedo fix and for some reason decided to put the soldering iron on both ends of the resistors where they attach to the gauge. Do you think it would be possible to replace the resistors (if so, what resistance) or do you think I might have fried the coil. There was no burn smell when I did this. Fixed the speedo and broke the temp gauge. :(

Re: temp gauge tops out, car not overheating, new sender
 

wakeing up the dead thread but i have something to ask :)

I drive Civic 91 ED7 D16A9 and since i bought it, i had a problem with my temp gauge or something else...
The story is that i turn my car and drive, the temp gauge is just fine (just a lil bit down from half) and when i stop and wait in a traffic jam, temp gauge suddenlu rises needle ande it goes to HOT so i have to turn on heating to reduce the temperature but few days ago i let it to go to the top because i was really angry but nothing hapened. It doesnt boil :/ And fan doesnt work... I drove the car just normally.

I changed the sensor that turns fan on, fan works when i wire it directly, gauge sensor is new also...thermostat is new, i did bleeding also...also i changed cluster to see if gauge is fail but its the same...and changed the radiator cap.

I dont know what to do else...i think my car is not boiling but i dont know how to fix that bad gauge showing?

Could it be that the wire of temp sensor is thin somewhere and it doesent make strong signal?

I asked a lot of people but nobody could help.

EDIT: Also i was thinking that maybe ground of the cluster is not good?

Re: temp gauge tops out, car not overheating, new sender
 

Back from the dead again.
I had the same issue, and purchased an oem sensor at 45.00!
And it worked.
After buying two aftermarket sensors.

Has this happened to anyone else before?

Sounds like it happened to some of the posters here, including OP