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1992 3/5 Temp Gauge Issue
Topic Started: Aug 17 2014, 02:45 PM (482 Views)
kick-rennedy
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So I've finally gotten the little Geo up and rolling. I'm having an issue with my temp gauge. When it's stopped it'll sit right in the middle, but when the car is moving, it's shooting up.Link to video here. I'm hoping that this is just in the thermometer in the engine, or maybe a bad switch.

Any clues?

Thanks,

Kick
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Memphis metro


video link does not work for me. Does the cooling fan ever come on?
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kick-rennedy
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Link should work now.

I had to wire the fan to run constantly when the key is on. It's spinning.
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freegeo
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If I remember correctly , unplug the wire going to the coolant temp sensor and ground it. Turn the ignition key to the on position and see if the temp needle goes to fully hot. Sounds like you may have a bad ground to the cluster. Is that the only gauge that does it?

Have you checked the water pump to make sure it is working?
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kick-rennedy
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Quote:
 
If I remember correctly , unplug the wire going to the coolant temp sensor and ground it. Turn the ignition key to the on position and see if the temp needle goes to fully hot. Sounds like you may have a bad ground to the cluster. Is that the only gauge that does it?

The fuel gauge seems to float, but I just chalked that up to the actual float in the tank moving. I'll give the grounding it out a shot.

Quote:
 
Have you checked the water pump to make sure it is working?

We ended up replacing the water pump when we put the new head on it. It should be working, I can see coolant flowing if I leave the radiator cap off of while it idles up to temp.
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freegeo
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You said you wired the fan to run constant. Do you know if the engine is actually running too hot. Should run hottest at a stop and idle unless your water pump wasn't working. You stated that the water pump had already been replaced.

Sounds like a bad ground possibly to the cluster.
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myredvert
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myredvert

In the video there was one shot of it about 1/2 needle width below the "Full" mark (@ 11 s), then after the temp gauge went up it looks like (maybe?) the fuel gauge was indicating about one needle width higher than the full mark (@ 13s). You shouldn't see the fuel gauge move while driving (ok, maybe in an automatic with a bit of a headwind, but it wouldn't be moving up :D ), which would suggest the cluster ground.

Did you find anything to solve the Check engine Light DTC 23 (IAT Sensor Circuit) code that was flashing? IAT sensor unplugged at the air filter maybe? Since the video only showed three cycles of the DTC 23, what happens next?

Each code will flash three times in sequence, followed by the next "higher" code if another one exists. After 3 cycles of the DTC 23 (IAT) code flashing, does it by any chance then flash a DTC 24 for the VSS? (which might also suggest cluster ground).

If you still have the fuse in the DIAG SW slot in the fuse box, remove it after you identify the code(s) that are set. ;)
Edited by myredvert, Aug 18 2014, 12:05 PM.
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kick-rennedy
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Any clue on where this ground should be? We're having trouble finding it.
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Metromightymouse
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Powdercoat Wizard

Start with the one on the intake under the throttle body. If they are attached then take them off, clean them up really well and bolt them up.
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myredvert
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myredvert

94 FSM shows the cluster using the ground described as "Left of Cigar Lighter on IP (instrument panel) Support."

97 FSM shows the ground on the back of the intake. Can't hurt to start there. Since I have not been in/behind my instrument panel, maybe someone can give you some good practical direction on the easiest way to find and access that one?

Did you get your DTC 23 code resolved? Were there any other codes?

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