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[RESOLVED] 2G coolant temp sensor question

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cudadrt

15+ Year Contributor
110
16
May 9, 2008
Maryville, Tennessee
I've searched and couldn't find what I'm looking for. I've got a 95 Talon TSi AWD turbo. I am having problems with a rough lopey idle and have found that the coolent temp sensor could be bad which is aknown cause for this. I went and ordered one for it but the one I got was wrong. My wiring harness has the T type harness like the early 1G's and was wondering if it was possible for it to be like that or if it's been switched? I've traced the wire and didn't see anywhere that it was spliced so that makes me think that they might have been possibly both in the 95's due to the body change possibly. Does anyone know of this being done or if it'll have a negative affect using the 1G sensor wiht the 2G ECU? Thanks in advance for any and all info. Going to replace the sensor in the morning with the 1G one and see if it helps. I will repost my results.

Dwayne
 
Well sorry I didn't get back any sooner. I replaced the sensor with a new one and it did not fix my problem. I'm not sure what's wrong but assume it's the fact that someone might have hacked the wire harness and put the 1G sensor plug in place of the 2G sensor plug. I'm going to try to find a 2G sensor plug that i can try swapping back in and see if that'll make any difference. If anyone has any advice or 2 cents to throw my way and anyone else who might come across this then please feel free to do so.

Dwayne
 
is the crappy idle only when you first get the car going or is it even after the car is warmed up? i had a CTS issue before but i only had a real terrible idle at start up and it would ride just fine once the car warmed up. as for your sensor itself... where did you order it from?
 
hey cud you're in my area. I would check the pull-a-part down there. I was down there last month and raped a 99 gs. They had a few 1g's also. But i'm sure you could find what you need there. And it is so cheap:D
 
hey cud you're in my area. I would check the pull-a-part down there. I was down there last month and raped a 99 gs. They had a few 1g's also. But i'm sure you could find what you need there. And it is so cheap:D

Thanks for the advice but I've already been there as well and wasn't anything much left I could use as I was hoping. Guess I got there too late.


is the crappy idle only when you first get the car going or is it even after the car is warmed up? i had a CTS issue before but i only had a real terrible idle at start up and it would ride just fine once the car warmed up. as for your sensor itself... where did you order it from?

The idle is lopey when it firsts starts as it hovers around 800-1000 rpm's. After it warms up it will climb to 2000-2200 on a cold day and stay there. As the weather is getting wramer the idle seems to be coming down as the outside temp goes up. Since the 60's and 70's are coming back the idle has been between 1000-1500 rpm's. I checked the engine temp on my laptop through DSMLink and it shows a constant 311 degrees even when the engine is cold. I've found a plug and am having it shipped here so hopefully will be able to replace the plug and put the 2G sensor in. As of right now I have the 1G sensor in and I got it from Advance Auto Parts. I'm thinking that maybe the sensors have different signals and it's not working with the ECU and could also be the problem with not getting over 10lbs of boost before it starts backfiring. And yes I've done boost leak tests over and over....just to eliminate that possiblity.
 
Ok I think I might be headed in the right direction. I've found that there are only 2 coolant temp sensor wires...one to the ECU and one to the gauge. I traced the plugs and found the one with two wires(one black and one black w/ white line) has a plug on it but it seems to be the wrong plug. It fits the plug on the 1G A/C temp switch. I'm almost sure due to the wires that it's the ECU coolant temp plug. Can I change the plug to fit the factory ECU coolant temp sensor? Here's a few pics of the sensor and the plug I'm refering to.
 

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Well after continuous serching, I think I've come up with a solution to anyone who may be in the same predicament. I think my wiring harness has been replaced with a 97-99 harness as the sensors are different for those years on the ECU coolant temp sensor. Info I found on here said ALL 2G's used the same sensor, but with further investigation I've found that there is a difference between the 95-96 and the 97-99 ECU coolant temp sensor. I've ordered one and is suppose to be here tomorrow. I'll repost when I've seen if this fixes the problem. If anyone has any ideas on this then they are still welcome and I appreciate those that have helped.
 
I'm hoping that it does...my car runs like total crap right now and my logger says the temp is 311 degrees...I know it ain't getting that hot as it stays there and never moves. I'll let you know tomorrow as I plan on getting it and installing it. I'll post back here and PM you.
 
Well I got the sensor today and it's the correct one. I also found out that the years aren't the difference in the sensors, but the models. The ECU cooling temp sensor that's called for a Talon is oval shaped and the ECU coolant temp sensor for the Eclipses are square shaped. From what I've discovered the eclipses (95-99) use the same sensor but the Talons show a different, oval shaped sensor. I've seen through searching on here that some people with Talons never seem to get the right sensor when they go to get one for their car so I'm assuming that some Talons have the same harnesses from eclipses and will require you to check the plug before getting the sensor. Here is the pic of the Eclipse sensor. The sensor pic above a few posts is what is called to be used on a 2G Talon and the one below is what's called to be used on a 2G Eclipse. Some Talons have the Eclipse plug for this sensor for some reason, so please be aware and make sure as to which one you have before ordering. Thanks again to all who've replied and hope this helps those out there with the same confusion.

Dwayne
 

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yeah i am replacing the connector as well, i can't find one. this guy gave me a web site right now that has the oem one but they are out of stock.. but idk if that one would fit right. . the one in the link .
 
Well they're pretty much the same price as the parts store. If you don't need to drive your car to get it I would recommend taking the old one off and just go to the parts store and get one. I have a 95 Talon but it actually used the sensor from an eclipse. I've posted two pics above of the difference between the Talon and Eclipse sensor although my Talon had the Eclipse sensor plug so I had to use the Eclipse sensor. The Talon ECU temp sensor is oval where the Eclipse ECU sensor is square.

What happened to the connector on it?
 
the pigtail is torn, but its un repairable, so i need to find just the pigtail. i dont really need the sensor but if it comes with the connection then that would help too.
 
I bought a pigtail supposedly for a 2G but when I got it it was for a 1G. That's when I discovered the differences in the sensor and ended up not needing it. If I had another pigtail or new where one was, I'd be more than happy to let you have it for shipping cost. I'll keep my eyes out for one or you can post in the want section looking for one. That sensor you're talking about getting with the connector looks like the right one though but maybe someone else can confirm the thread size to be sure.
 
Sorry to bring this back from the dead, but this post has the most accurate description of my problem. But with more issues!

I have a 95 talon (sensor with oval connector). Autozone had wrong one, so did Advance Auto (square connector). Finally I went to NAPA, and they had the oval style connector. HOWEVER, it gave the wrong temp reading to the ECU (verified by Link). Although my temp gauge was pegged, my ECU read like 180 degrees. I measured the sensor with my ohm meter, and the readings were not per the service manual. I recall the manual saying it should read 2200-2500 ohms, and the one I have reads well over 10,000 when at room temp. I exchanged for another one and the same thing. Finally, I said screw this and ordered an OEM one from J&Z...it had the square connector! (At the time, I did not find this post which explains the Talon and Eclipse has different connectors for the CTS)

So, just because it 'fits' doesn't mean it works. It may eliminate your CEL, but the ECU will not work properly. (My fans don't even turn on!)

Does anyone have the OEM partnumber for a 95 TALON CTS? or know where to get one that works? If you bought one locally and know it reads properly, please let me know!!
 
This is a current issue I am having. My fans will not come on and temp gauge seems to be running in the middle of the range now/ randomly higher. I replaced both the 2 wire sensor and the single wire sensor. I have a talon with the rounded square and changed over to the eclipse style even more round/oval ish because I couldn't find the other one anywhere. I am wondering if the eclipse one is completely different of if it would be in spec if it was a Mitsubishi part. I got it from autozone so mmv.

I actually had to mod my drivers side fan to turn on with ignition because my temp gauge would say the car was getting too hot but the fans never turned on.

My idle would rest at 1400 RPM most of the time and sometimes spike to 2500 RPM then settle it would be erratic as all hell.

Currently my ECU is reading that its -0.4f on cold start temp which is not possible because its about 50*f outside right at the moment. Having terrible cold start flooding issues, it will flood so bad that the car dies and I have to disconnect the fuel pump to un-flood it or it will crank for years and never start.


Just checked the rounded square one I have reads 2,000 ohm at room temp and resistance goes down as it warms up. The eclipse one reads 10,000 ohm and 14,000 outside (outside temp is 50*)

Edit: I just went out and tested a theory.. I watched the ECU while I unplugged the (eclipse) sensor and it dropped from -0.4*f to -40*f and I could hear a valve open and close. Then I plugged in the wires from the rounded square sensor and watched the ECU read 66*f (about what it is outside)

Watching the values via OBD2 reader and torque I can tell that the eclipse one while reading something is not reading in the same value range for ohms as the rounded square plug talon one. This worries me because that means when the car is warm its hard to say if its 60* or so off when reading that too.

Correct Part no.
Through Duralast SU4293 Correct for talon will read around 2,200ohm rm temp.

Wrong Part no.
Through AirTex 5S1029 For eclipse only will read 10,000ohm - This is wrong for 95 talon ECU *possibly effects some 2ga eclipse.

Should read around 2200 Ohms between the metal pins at room temp for 1995 Talon ECU

I checked the sensor against the factory one I pulled out and the ohm readings are close. The eclipse one will take your CEL away but your fans wont come on. There is from my findings about a 60* difference between the actual reading and what the eclipse sensor reads. I was getting a CEL before for insufficient operating temp, which I have now tracked to likely being my radiator cap was not sealing properly. What a mess.

Edit 2: I just swapped the pig tales (soldered the rounded square one back in) and changed over to a new talon part no. SU4293 and bingo ECU shows that coolant temp is 43*f which is about what it should be its around 50* outside. This issue is something I have battled with for a while now I understand why it was working but was wrong. This may have aided my overheating issue I experienced last year how unfortunate. This seems to be a talon ECU related issue and or it came about when the 1994 to 1995 change over happened. So some eclipse ECU's may have this going on as well.

Edit 3:
Car is running much smoother and idle is about 845 RPM Which it never settles that low so obviously this is better. My fans still do not come on. I will be keeping fan on with ignition mod.

Edit 4: it gets even better my temp at 70mph was 219* with both fans on, heat on full and the hood popped (I was in emergency protocol mode) so I pull into a gas station hour away from town. This is driving me crazy it doesn't seem right why the temps suck. I figure what do I have to lose I'll take out the thermostat. I pull it out decide I need the gasket in there so I pull the thermostat open to the fail safe locks on it and pop it back in. It's now permanently open. Cruising temp achives 160* both fans off and heat on low. Placing an order for a mitsubishi thermostat.
 
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Good post and excellent troubleshooting. I never had the fan issue, but then again I am running DSMLink and keep my fans on all the time. Glad you got your solved and working correctly. Hope this helps others out there as well.
 
If you had to swap plugs it was the wrong part. Dont know why you woudve swapped. It isnt an eclipse vs talon issue.more liklely a turbo vs non turbo issue.always cross reference. Part store part numbers are often wrong.
 
It's a talon ecu difference from what my research pulled up. It's literally only the 2g talon ecu that is made to look for 2000ohm temp sensor. The Eclipse one I'm pretty sure is the other part Napa and autozone only pull up the (more oval) part number one for all turbo Eclipse models. The weird rounded square one the only difference is the plug and the ohm reading. In some bizarre happening maybe autozone and Napa have errors in their database but I'm not sure I'll check my buddy's Eclipse gsx and let you know what plug is on his.

I figured it out, I was using a 1g temp sensor the parts listed for 2g in some databases a are 1g for 1995.
 
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Good post and excellent troubleshooting. I never had the fan issue, but then again I am running DSMLink and keep my fans on all the time. Glad you got your solved and working correctly. Hope this helps others out there as well.
If you have to keep both fans on all the time I think you might want to inspect your thermostat.. I did not think that our radiators stock were as efficient as they really are. One fan running is enough to make mine run cold with the thermostat open I actually had to block off half the radiator to get my temps in the 170's while on the highway. I would say that in 70* weather my radiator is so overkill that I could see going to a half sized one removing the thermostat and just running a single fan on a temp switch. I didn't think it was possible before, but the thermostat will trick you into thinking you need a mishimoto radiator when in reality the stock setup is overkill. Who knew.
 
I just run them all the time on purpose. It don't have any negative affect on doing so. I've always run aftermarket fans with ignition on with all my cars. I do with my supra and my muscle cars as well.
 
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