Fluctuating temperature gauge

[supra_man87]

I have found similiar threds but they where for other gauges (fuel gauge...) but i've had some wierd experiences with my coolant and temperature lately so i'm not too sure of what is is. if it is a ground with the electrical system, it would be cool if you could tell me where they are. so this is what happening. when i drive my car, and i step on the gas, the temp shoots down to "C" then wobbles back up. here is a video. http://s116.photobucket.com/albums/o26/jq_87supra/?action=view&current=IMAG0002.flv ths was shot when my car was sitting for a while. its worse when its warmed up. thanks

i forgot to add that my temp sensor has been changed and the cooling system has been replaced

 

[ratpick63]

make sure connection on temp sensor is good. Temp sensor operates by changing it's resistance to ground as temperature changes (signal to gauge) I'm not for sure of the calibration for sure, but cooler temps are probably higher resistance and resistance going down as it gets hotter. Which means if the gauge is on and looses signal (infinite ohms to ground) it will try to show this as all the way cold. Could be vibrating loose as it revs.

Also, double check that no air in cooling system. I'm sure you know these cars are hard to fill cooling system without trapping air. I just repaired a leak in a hurry and had air pockets, my temp gauge was bouncing all over on my way home. But mostly just rushing towards hot til it flowed again and then going back down. Probably bled air from system and it's all good now.

 

[TRG22]

Got the same problem, be interested to find out how you fix it.

Slightly worse problem than yours, think it illustrates it quite well though. Excuse the noise, had the heater going and it was peeing down...


http://s219.photobucket.com/albums/cc249/TRG22/?action=view&current=MOV00011.flv

 

[Anicrow]

I was having something like this happen, temp kept rising sitting still..

The fuse for the Temp-fan was carroaded away, might be worth checking, all I did was scrape off the contacts and it worked find. (Replaced the thermostat and everything)

Seems like it's more complicated then that though ^^.

 

[CyFi6]

might be worth the time to take out the gauge cluster and check the connections on the back, theres screws that hold the temp gauge in which also act as contacts for power.

 

[87nasupra]

When i first got my car mine was doing the same thing. I did plugs and plug wires. I'm thinking maybe interference from a wire breaking down? Mine has NEVER done it since......Except for my past BHG, haha. Good luck

 

[TRG22]

When i first got my car mine was doing the same thing. I did plugs and plug wires. I'm thinking maybe interference from a wire breaking down? Mine has NEVER done it since......Except for my past BHG, haha. Good luck

Moved the HT lead away from the sensor wires going over the back of the cam gears, and the problem miraculously disappeared. Its a new item so should not be breaking down but if its fixed it...!

supra_man87 try this and see what happens, you never know.

 

[supra_man87]

Moved the HT lead away from the sensor wires going over the back of the cam gears, and the problem miraculously disappeared. Its a new item so should not be breaking down but if its fixed it...!

supra_man87 try this and see what happens, you never know.

well when it first started doing this, it was like 50 degrees outside, and today when i drove it, it was perfectly fine. so idk.

 

[supra_man87]

well up untill now it was fine. now its doing it again. i've replaced the guage with another one, but still doing it. i was thinking there is a bad ground. i went to my toyota today and they said that there are two grounds. one that grounds to the engine, and one that grounds on the intake. i'm pretty sure its the one on the intake. does anyone know exactly know where its is? of if anyone knows the problem still?

 

[cuel]

Check the connection at the sensor, for a dirty or loose connection. You can test the gauge by grounding the harness connector at the sensor. The gauge should move all the way up, evenly.

 

[AJ'S 88NA]

well up untill now it was fine. now its doing it again. i've replaced the guage with another one, but still doing it. i was thinking there is a bad ground. i went to my toyota today and they said that there are two grounds. one that grounds to the engine, and one that grounds on the intake. i'm pretty sure its the one on the intake. does anyone know exactly know where its is? of if anyone knows the problem still?

They are under the intake mounted on the intake.

 

[labrat469]

Could also be the old gauges just wearing out with time. I found both of my oil and temp gauges inaccurate so I replaced the gauges with after-market gauges.

 

[supra_man87]

the temp sensor is new, and i have a new toyota gauge. so i'm thinking of seeking that ground. and i don;t have too much money to buy new gauges. and what are some that fit in the gauge cluster?

 

[AJ'S 88NA]

Have you checked the wire that goes to the temp gauge. Mine was fluctuating and the wire just needed some attention.

 

[supra_man87]

Have you checked the wire that goes to the temp gauge. Mine was fluctuating and the wire just needed some attention.

which wire would that be. remembr the gauge makes connections with that ribbon wannabe chip thing and then it goes where?? i found the ground, and i wire wheeled evrything on it. no word yet if it worked. any other grounds or anything else?

 

[Sportriderseattle]

oh I am soo glad someone did a post on this. Mine does this after it has warmed up usually atleast 5 minutes after startup on a cold engine. My gauge can do it also when revving the engine but it also just does it at a steady rev, like cruising on a freeway. I've even had mine spastically jump up and down violently then relax after a couple seconds, leading me to believe it was a ground or atleast a wire loose.

 

[AJ'S 88NA]

which wire would that be. remembr the gauge makes connections with that ribbon wannabe chip thing and then it goes where?? i found the ground, and i wire wheeled evrything on it. no word yet if it worked. any other grounds or anything else?

I don't understand some of what you are talking about, but the sensor wire is on the left side of the housing that the thermostat is mounted on, if memory serves me right, it's yellow. Check to make sure of your connection, I had to pinch the conector a little to make a good connection.

 

[supra_man87]

I don't understand some of what you are talking about, but the sensor wire is on the left side of the housing that the thermostat is mounted on, if memory serves me right, it's yellow. Check to make sure of your connection, I had to pinch the conector a little to make a good connection.

we are talking about that there is a ground that the guage goes to. its underneath the intake manifold. and my gauge is a bit better, but still is all over the place. i also heard that there is another ground that is mounted on the block. does anyone know exactly where it is at? it is getting anoying seeing it wobble around

 

[AJ'S 88NA]

we are talking about that there is a ground that the guage goes to. its underneath the intake manifold. and my gauge is a bit better, but still is all over the place. i also heard that there is another ground that is mounted on the block. does anyone know exactly where it is at? it is getting anoying seeing it wobble around

I don't know of a ground that goes to the gauge, the ground that goes to the block, there is one under the intake that is the battery ground, three that connect to the intake manifold, one that connects to the head on the left side and one that connects to the tranny support.

There is one wire that goes to the sensor on the housing for the thermostat. Like I said check the connection that goes to that sensor, it's what caused mine to do the same thing.

 

[supra_man87]

fixed!!!!!!!!!! Sportriderseattle check your pm.