Coolant temperature switch problem

[rated x]

I must really have some bad luck!

I was able to change the fuel line I busted right off the tank and all was fine.

Now this is where it gets confusing.
I went to start the car and noticed the fans kick on without the car getting up to temp.I tried turning the fans on and off on dsmlink and they still stayed on.I know this is not normal so I turn the car off and disconnect the battery to reset everything.So I reloaded my settings on dsmlink back into the ecu,I go to start the car and I get the same $#*t again.So I started to log and see what's going on and noticed that not only is my coolant reading -40 but my 02 sensor looks like it's not cycling.It didn't want to move from .10v and when I reved it up, it didn't want to pass .12v.I'm guessing it has to do with the temperature being so low.I replaced the o2 and both temp. sensors to see if that fix the problem and It's still doing the same thing.

What else can I look for?Please help.Thanks.

 

[Rice Over Wheat]

Well I don't get why your coolant reads -40 yet the fans come on when the ecu thinks it is freezing? And for the O2 and engine temp sender to go bad at the same time... Have you looked at the ecu yet?

 

[rated x]

Yep, Check out the pics.Plus I know it's not the ecu since I plugged in my old ecu and it still had the same problem.Someone please help.

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[pneumo]

Check the wiring to the coolant temp sensors. -40 is the same as getting no signal from the sensor.

 

[rated x]

I changed the sensor with a new one and pulled apart the plug to it and the connection is good.

 

[rated x]

I switched the ecu out with my stock one and still got the same problem.It has to be something else.Does anyone have any ideas what could cause this?Thanks.

 

[RipperXX]

Check the wiring to the coolant temp sensors. -40 is the same as getting no signal from the sensor.

I changed the sensor with a new one and pulled apart the plug to it and the connection is good.

Check the WIRING, just because you replaced the sensor doesn't mean the ECU can see the signal if the wiring is bad.

 

[rated x]

Can someone tell me where does the wires run to from the sensor to ???I checked the plug and took it apart and seen nothing wrong with it.I just don't know where it's routed and I really don't want to tear apart the harness.

 

[pneumo]

Pin #83 is your coolant temp wire to the ecu.
www.VFAQ.com/mods/ecu-harness-2G.html
Get a multimeter and check continuity between the coolant sensor plug on the thermostat housing and pin #83.

 

[Dark_Horse]

So you replaced both the coolant temperature sending unit and the coolant temperature sensor on your water neck? There's 3 sensors on the water neck. The coolant temp sensor, coolant temp sending unit and the AC fan temp sensor.

The sensor at the top is the AC fan temp sensor. If you replaced the bottom 2, then it's a problem in your wiring.

Since you're reading -40, you have no startup enrichment and your O2's will pretty much never cycle. It's definitely the coolant temp sending unit and not the coolant temp sensor.