Cooling Fans Not Working

[Talonman86096]

Ok really long story but I am having problems with my cooling fans not turning on in my 96 Eagle Talon TSI FWD. A while back I had a new temp. sensor put in which corrected a problem but i think lead to this one. For some reason there is a ground wire from the temp. sensor to the negative termanial of the battery. And now for some reason my cooling fans will not turn on by themselves, if i turn the A/C on they will come on and turn off just like they should on their own. If you disconnect the ground wire from the battery the car will not idle right and just run like crap and the check engine light will come on and the cooling fans will run all the time and not turn off. Ive had it to 3 or 4 different shops and no one can figuare this out i am completly stuck and have no idea what is wrong. Also it idles to high and the gas seems to burn extra rich idk how to correct that problem either. I know there is an idle screw somewhere but i havnt located it yet. If ne one has had a similar problem to this or has any ideas of what could be wrong i would appreciate it. I just had a brand new Big T28 turbo and 3" turbo back exhaust put on but this problem had occured way b4 this and is the only thing wrong with the car and its driving me nuts. Ne help will be greatly appreciated. Thanks

 

[bluetlr2001]

Heres a link that will show you were your idle adjustment screw is,
http://www.vfaq.com/mods/BISS-2G.html

As far as your temp switch. You have to different switchs one is the sending unit and the other controls what temp your fans kick on at. But i dont think one of the wires should go strait to the battery. I do know one of the wires on the control switch should be a ground because when your car reaches a certain temp it outs ground on the other wire to activate the fans. You have relays under the hood for your fans to. But if you want to bypass the relays and the temp wsitch here will show you how to rewire your fans,
http://www.vfaq.com/mods/wayback/2gcoolingfan.html

 

[Talonman86096]

Both wires still come out of the temp. sensor the red wire looks like an added thing for some reason. Ive had my mechanic look at the wires and they go where they should from the temp. switch but i dont know why the red wire was added other then it makes the car run correctly. Also so adjust the BISS do i have to have that other peice of equipment it says or is ok to just adjust it without it. Do you think that would correct it from burning rich possibly? Thanks for the help i appreciate it

 

[bluetlr2001]

You can adjust it with out the computer it want be perfect but it may help. As far as your running rich problem have you done a boost leak test to see if you have a leak.

 

[luv2rallye]

For some reason there is a ground wire from the temp. sensor to the negative termanial of the battery. And now for some reason my cooling fans will not turn on by themselves, if i turn the A/C on they will come on and turn off just like they should on their own. If you disconnect the ground wire from the battery the car will not idle right and just run like crap and the check engine light will come on and the cooling fans will run all the time and not turn off.

Your problem is due to the fact that someone connected the sensor to chassis/engine ground (battery negative) instead of ECU SENSOR SIGNAL GROUND. These 2 grounds are NOT the same. When you connect to chassis ground you would get exactly the symptoms you describe since ALL the MFI sensors signal grounds are also tied in to this one so the engine will run like crap. Not all sensors have a signal ground (some use chassis ground) but most of the MFI ones do. Remove that ground wire and connect that sensor's pin 2 (black wire - not pin 1's black/white wire) to ECU pin 92 (or to one of the other MFI sensors signal grounds black wire that also go there (O2, Manifold Diff Press Sensor, Throttle Position Sensor, Volume Air Flow Sensor, or fuel diff pressure sensor). If engine still runs like crap make sure there is continuity from those sensor signal ground wires to ECU pin 92.