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Author Topic: P0128 Won't go away!  (Read 1398 times)

Offline Axle

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Re: P0128 Won't go away!
« Reply #15 on: March 06, 2015, 07:58:14 AM »
all parts are crap these days. use a good name, like Stant.
85 cj-7

Offline Corey G.

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Re: P0128 Won't go away!
« Reply #16 on: March 06, 2015, 08:53:09 PM »
all parts are crap these days. use a good name, like Stant.

I replaced the thermostat again today. The one I took out was Stant, replaced with Gates last weekend (made in USA), and replaced again with Duralast today. Still doing the same thing. The dash gauge goes back and forth between 180-200.

I'm wondering if the temp sensor I got was junk, and the thermostat actually was the problem. Before I replaced it and the tstat last weekend, the gauge was showing 210. Unfortunately I can't put the old sensor back in since I broke it when I took it out.
« Last Edit: March 06, 2015, 08:58:20 PM by Corey G. »
2006 LJ

Offline Twisty

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Re: P0128 Won't go away!
« Reply #17 on: March 06, 2015, 10:40:18 PM »
dash gauge goes back and forth between 180-200.

The Yj that I'm having issues with in the Tech forum is doing the SAME thing.  Temp gets to 210, then drops to ~150.  Then goes up to 210 and drops to 160.  It keeps doing it until it reaches ~200 then kind of stays there.


Duralast t-stat swapped in a few weeks ago.
88 MJ buggy, 4.0/AW4, 203/205, 3 link front/4 link rear on airshocks, 42" Iroks, full hydro

"Only wealthy men can afford to buy cheap things."

Offline Posimoto

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Re: P0128 Won't go away!
« Reply #18 on: March 07, 2015, 09:42:26 AM »
all parts are crap these days. use a good name, like Stant.

I replaced the thermostat again today. The one I took out was Stant, replaced with Gates last weekend (made in USA), and replaced again with Duralast today. Still doing the same thing. The dash gauge goes back and forth between 180-200.

I'm wondering if the temp sensor I got was junk, and the thermostat actually was the problem. Before I replaced it and the tstat last weekend, the gauge was showing 210. Unfortunately I can't put the old sensor back in since I broke it when I took it out.
Confirm their good or bad, don't guess. The t-stat can be tested in a pan of water and a temp gauge. Suspend the t-stat so it doesn't touch the bottom of the pan and turn up the heat. Should start to slowly open around 185-190. You can test the temp gauge by removing the plug and testing the pins when cold then hot, or probe the coolant temp sensor signal at the ecm and watch for a steady voltage movement.   
"That's the trouble with research on the internet, there's no way of verifying its truth" --Abraham Lincoln

71 CJ5 V6/T14/D18/Warn OD (from CO)
79 CJ5 304/T-150 Silver Anniversary
79 CJ5.5 360/T-18/4.1 D-300
77 CJ5 360/T-18/3.15 D-20
77 CJ7 258 Fuel Injected T-18/D-20 (from CO)


 



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