95.5-2004 Tacomas & 96-2002 4Runners 4th gen pickups and 3rd gen 4Runners

Temp Guage

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Old 12-18-2003 | 02:41 PM
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Temp Guage

I just purchased a 1994 4runner v6 auto 4x4. I had to have the crossover pipe and gaskets replaced and the muffler. Now I noticed that the temp guage was going nuts vibrating back and forth until yesterday that it remaind fixed on the red section. The truck is not over heating at all. I think it is the sending unit I was hoping that someone could tell me where on this block is the temp sending unit located? Not familiar with toyotas. Let me know if you think this problem may be something else. I also have noticed it is not as powerfull as I expected it to be. It does have oversized tires 32's I think, not sure will bring in exact specs. Any help will be greatly appreciated.
Old 12-18-2003 | 03:06 PM
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dlorenza: The temp sensor on the 3.0L is located in the coolant by-pass outlet which is on the back of the motor, between the firewall and the underside of the intake plenum. This is right above some of the exhaust plumbing you had worked on. There is an aluminum tube that carries coolant up from behind the thermostat and ends right next to the coolant by-pass outlet. There is a u-shaped rubber hose that connects this tube to a nipple on the coolant by-pass outlet. This tube,through the bowels of your 3.0L and bolts to the back of your motor......it also runs right by your exhaust plumbing. This tubing has probably become loose and is now touching the hot exhaust, thus heating the coolant up making it look as if is hotter than the motor really is. The sensor is down-stream of the flow from this tube and it is reading the hotter temps.

I would have the shop that did the work check it and fix the problem. It may be a simple bend it out of the way fix. But be careful, if they bend it too much and it breaks, that tube requires gutting of the engine to replace.

David
Old 12-18-2003 | 03:15 PM
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temp guage

Thanks for the info. Based on that would the hot temp on the guage lock in even after a cold start after sitting all night? Because I parked it last night around 6pm and started it today at around 8am and it was still tilted? any more info will be appreciated.
Old 12-19-2003 | 06:42 AM
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You might have fried the sensor......or the sensor wires might be grounding together......it all depends on what was shoved or moved around back there when the work was done. To me it is sounding more like a sensor/sensor wiring issue rather than a heat related thing. You can look back there with a light and check things out and maybe determine what is going on. Try unplaugging the sensor and see if the gauge goes to zero.
Old 12-19-2003 | 08:27 AM
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From: paddling out on the right coast
by chance, anyone has a picture of the location of the temp sensor.
Old 12-19-2003 | 09:04 AM
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temp guage

yeah a pic of the location of the temp sensor would be great if anyone has one. Thanks
Old 12-19-2003 | 09:10 AM
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I don't have a photo but here's a copy of a part of the FSM

FSM

Look on page 10 and you'll find an exploded view of the Intake Manifold. The temp sensor screws into item number 6 on this drawing....... the sensor isn't identified on the drawing but this is where it goes.
Old 12-19-2003 | 09:18 AM
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temp guage

this is great. Thank you so much I am on my way to check this out!
Old 12-19-2003 | 09:43 AM
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temp guage

went to take a quick look and I see 3 sets of wires going to 3 seprate sensors? any clue which one it is? Don't want to cause more damage.
Old 12-19-2003 | 10:04 AM
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From: paddling out on the right coast
thanks!
Old 12-19-2003 | 10:41 AM
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temp guage

Found it thank you so much for everything!!!! I am now off to troubleshoot this thing.
Old 12-19-2003 | 12:00 PM
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I went and removed connection to temp sending unit and it still regestired the same with the differance of the check engine light coming on. Maybe a ground wire. Does anyone know where I can check the ground wire for the temp guage???
Old 12-19-2003 | 12:27 PM
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From: paddling out on the right coast
i'm still at work... was it easy to get to the temp sensor?
Old 12-19-2003 | 12:50 PM
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It was not to bad if you have small hands and or are willing to remove some tubes and such. go here and there is a drawing of the exact location on page 11 http://www.net-impress.com/4runner/cd/G_TESTS2.PDF that along with the previous drawing should give you all that you need. I have to track the ground wire for the guage if anyone has any insight let me know. PLEASE
Old 12-26-2003 | 02:54 PM
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I am still having trouble with my temp guage. I have checked the sending unit it is fine I have also checked the pipe near the exhaust and it looks good. I was hoping someone would have the wiring schematics for a 1994 sr5 v6 runner. I am thinking it is grounded somewhere? when cold it shoots up to about half way mark and in seconds reaches maximum temp. The truck is not over heating. Please let me know if anyone has any idea about how to fix this?

Diego.
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