Coolant Temp Sensor wires were cut..

[az94subaru]

Hi. I have had problems with my 94 Legacy (temp gauge goes above halfway-close to Hot). Heads have been re-done. We have replaced just about every part regarding the issue. My friend attempted to change out the coolant thermostat sensor a few days ago, but had trouble trying to get the sensor out, so he cut it off (cut the pigtail wires) . This is a part that Subaru said they don't sell.

Now my car wont even start, as if it isnt getting any fuel. When my friend installed the new temp sensor (but not wired due to he cut the wire), both fans ran continously, whereas before the fans would not come on. Drove the car home and that was the last time the car would start/run.

 

 

1. How would my friend fix this other than get a new wiring harness? Would he be able to splice the wires together?

 

2. If my friend is able to re-connect (splice) the coolant temp sensor wires back together, should the car start (I am assuming by cutting the wires, has messed up the computer and this is why the car will no longer start).

 

Any suggestions or advice would be greatly appreciated!

Thank you...

[1997reduxe]

This is probably stupid, but there's fluid in the cooling system?

You replaced the radiator?

Not that it has anything to solve your wiring problem, but

I used to have a real slow leak in my radiator.

I would mostly remember to keep filling, but once

I forgot or ignored for a long time, and

it started overheating like what you're saying.

[az94subaru]

Yes, we have recently replaced the radiator, water pump, thermostat, coolant temp sensor (though not re-wired after wire being cut), fans.. coolant in radiator and overflow.

Edited January 30, 2012 by az94subaru
edit to add

[naru]

Hi. I have had problems with my 94 Legacy (temp gauge goes above halfway-close to Hot). Heads have been re-done. We have replaced just about every part regarding the issue. My friend attempted to change out the coolant thermostat sensor a few days ago, but had trouble trying to get the sensor out, so he cut it off (cut the pigtail wires) . This is a part that Subaru said they don't sell.

Now my car wont even start, as if it isnt getting any fuel. When my friend installed the new temp sensor (but not wired due to he cut the wire), both fans ran continously, whereas before the fans would not come on. Drove the car home and that was the last time the car would start/run.

 

 

1. How would my friend fix this other than get a new wiring harness? Would he be able to splice the wires together?

 

2. If my friend is able to re-connect (splice) the coolant temp sensor wires back together, should the car start (I am assuming by cutting the wires, has messed up the computer and this is why the car will no longer start).

 

Any suggestions or advice would be greatly appreciated!

Thank you...

 

1.Yes,splice.Super easy.I`m having trouble understanding why this hasn`t already been done.Sounds like the wrong person is working on your car.

 

2.Yes,it should start.Computer is not messed up.Spark plugs might be fuel fouled though.Pull and dry if needed.

[Fairtax4me]

It won't start because the computer is thinking it is WAY cold outside so it's dumping fuel by the truckload into the cylinders, making the mixture too rich to burn and fouling/flooding the plugs.

 

Splice the connector back on and plug it in.

[Mike104]

If they cut the wires too close to the connector to splice it, go to a junk yard and cut a section of wire from the temp connector and splice that in.

 

I have a sad story about having someone that doesn't know what they were doing recovering an expensive airplane for repairs. The damage caused by the recovery operation (cutting every wiring harness, fluid line and flight control cable) instead of using the installed disconnects was more expensive that the cost to repair the damaged caused because of the incident!

[WoodsWagon]

The temp sensor your friend cut the wires to is the one the computer uses to monitor the engine. The sensor right next to it with a single spade connection is the one that runs the gauge on the dash.

 

So not only did your friend hack the engine wiring harness, but he replaced the wrong sensor. That is, if the engine isn't actually overheating and the gauge is actually working perfectly.

 

You can cut an splice another connector onto your harness, or you can replace the complete engine harness. It's easier to do if you pull the intake manifold off, but I wouldn't recommend letting your friend do that if he can't replace a simple sensor without butchering things.

 

The reason it won't start and the fans run continuously is because the computer has no idea what temperature the engine is anymore. It sets a code for a faulty temp sensor and turns the fans on continuously because it's safer to have fans cooling an engine than no fans letting it overheat. It also runs the engine on it's up-to-operating temp fuel map, which is too lean to start a cold engine on. It's like having no choke on an old carbed engine.

 

To get it started, you can splash a couple tablespoons full of gas on the air filter, then snap the airbox back together and start it. It will run rough until it warms up. Then you can drive it to a competent mechanic (not your friend) and have them fix what's actually wrong with the car and splice the harness.