Author Topic: 97 tj 2.5 temp gauge bouncing wildly.  (Read 1004 times)

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Rio_Grande

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97 tj 2.5 temp gauge bouncing wildly.
« on: September 18, 2014, 07:56:03 PM »
My 97 was down for about 3 years with the head off. I reassembled it replaced radiator, hoses, thermostat,, everything except the water pump. I know I even had it sitting on the shelf. Put it all back together drove it about 100 miles and the water pump blew.  Towed it home tore it down where it sat without the water pump for about 4 months. Reassembled with new pump. After adding coolant and bleeding, roughly 2 gallons and whatever it took to fill resivour. Drove it on a few short trips and everything seemed fine, had to add a little fluid. Yesterday I took it to get my kids from school about 20 miles. When we came out to go I noticed some coolant leaking on the ground, maybe 2 inch circle after sitting an hour. Under the hood there were a few drops of coolant near the rad cap but nothing alarming. On the way home the temp gauge began fluttering wildly. Never going over 210 but falling completely to the bottom as if the ignition was off. Then it would bounce up and down. The jeep never overheated no engine noise, just crazy gauge. I figure I will start by cleaning the connector on the temp sender and go from there. Any of this sound familiar? Any idea what's going on?

Offline sharpxmen

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Re: 97 tj 2.5 temp gauge bouncing wildly.
« Reply #1 on: September 18, 2014, 07:58:20 PM »
thermostat
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
Latest: Corbeau BajaRS heated seats :dance: keeping warm the rear end

Offline jfrabat

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Re: 97 tj 2.5 temp gauge bouncing wildly.
« Reply #2 on: September 20, 2014, 09:10:45 PM »
My bet is on the temperature sending unit (the one on the rear of the block, not the one by the thermostat)
'94 YJ 2.5L with 4" RE lift, Superwinch EPi9.0, FoMoCo e-Fan, SD30 and SD35 w/ARB-5.13, 165A alt., 33" BFG KM2 on 15" AR wheels, Sony sound system, Pavement Ends Hardtop, Hydroboost

Offline grumpygy

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Re: 97 tj 2.5 temp gauge bouncing wildly.
« Reply #3 on: September 21, 2014, 10:01:07 AM »
My bet is on the temperature sending unit (the one on the rear of the block, not the one by the thermostat)

Plug broken, I'm also for the sending unit.  Thermostat would not take it to zero.
94 YJ, Cool Air intake, 19lb Inj, 4.0 Throttlebody with spacer,  31/10.50/15's

Offline sharpxmen

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Re: 97 tj 2.5 temp gauge bouncing wildly.
« Reply #4 on: September 23, 2014, 12:11:46 AM »
My bet is on the temperature sending unit (the one on the rear of the block, not the one by the thermostat)

he's got a TJ, that only has 1 sending unit in the thermostat housing, the gauge is controlled from the PCM, so it's either the thermostat or the gauge itself - after reading the original post again (he says is going down to the bottom) I agree with grumpy that it is not the thermostat, my bet a wire, connection or maybe the gauge - just thinking that the sending unit being used by the PCM might throw a code but who knows, I guess that's probably the easier one to check so maybe start there.
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
Latest: Corbeau BajaRS heated seats :dance: keeping warm the rear end

Offline jfrabat

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Re: 97 tj 2.5 temp gauge bouncing wildly.
« Reply #5 on: September 24, 2014, 11:18:10 PM »
I did not know TJs used only one sensor...
'94 YJ 2.5L with 4" RE lift, Superwinch EPi9.0, FoMoCo e-Fan, SD30 and SD35 w/ARB-5.13, 165A alt., 33" BFG KM2 on 15" AR wheels, Sony sound system, Pavement Ends Hardtop, Hydroboost

Offline sharpxmen

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Re: 97 tj 2.5 temp gauge bouncing wildly.
« Reply #6 on: September 25, 2014, 11:40:47 PM »
I did not know TJs used only one sensor...
only one, they don't have the gauge sensor in the head (no hole either).
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
Latest: Corbeau BajaRS heated seats :dance: keeping warm the rear end