coolant temp sensor problems......

i have a 92 gmc 1500 with 4.3L .. i was haveing a problem with my coolant temp sensor.. my service engine light came on and i checked the code and it was 15 .. which is coolant temp sensor.. so i changed it now the light is still on and it is worse than it was.. is there a certain way it should be put in or do you just unscrew the old one and screw the new one in..or could it be the connection. or what could it be.. pls help it is causeing my truck to flood out and smokes like a freight train and its white smoke.. pls help .. thanks

White smoke is usually water/coolant. Are you sure it is white?

You replaced the temp sensor in the intake manifold, right?

The sensor will have a higher resistance when cold and if you suspect a wiring issue, you will have to measure the resistance at the ECM harness.

//2000CAYukon

yes i am sure its white.. when i crank it it starts and stumbles like its getting to much fuel.. and when it does run it blows a huge cloud of smoke out the tail pip.. yeah i changed the sensor that is right beside the thermostat housing.. and do you have to put thread sealer on the threads the one i took out had a what looked to be teflon tape or sealer on it.. not sure whats up i have taken it out and put it back in to make sure it was in far enough.. pls help.. i can't check the ecm i don't have a scanner.. any other options thanks and god bless

You need to see what the resistance is across the 2 pins of the new temp sensor. See the chart on this page http://www.explorerforum.com/photopost/showphoto.php?photo=30138&size=big&ppuser=42004

If the engine is warmed up, you can bypass the temp sensor with a jumper wire at the temp sensor harness. This will tell the ECM that the engine is very warm and it should not be using as much fuel at that time. If that does not help, you have a bad wire to the ECM or to ground. The ground for the temp sensor is either at the tstat housing or at one of the intake manifold bolts.

//2000CAYukon

thank you so much for your assestance.. you have helped alot.. i just have one more question how would i go about useing a jumper wire like you said.. i am just of basic knowledge of this truck.. what do i just jump the two connections to the battery or what not real sure what you mean.. i am pretty good with electrical just not sure how it coud be done.. thanks man and god bless

When you unplug the temp sensor, there are 2 wires in the plug for the temp sensor. You want to jumper the 2 wires in that plug. This bypasses the temp sensor.

Note that if you have a bad ground or wire, this probably won't help but does help rule out the temp sensor as the issue.

//2000CAYukon

ok i kinda understand but do i just jumper the two prongs to each other or what.. and you are talking about the plug that goes into the sensor right.... sorry for my ignorance.. would the likely hood of a bad ground be the problem .. because before i changed the sendor the light just came on and then went right back off .. but now the light stays on and it starts crappy after it runs and warms up . once its started t runs fairly good.. thanks for the help man i greatly appreciate it..

I am talking about the plug. Here is an example: http://images.google.com/imgres?imgurl=http://www.alfabb.com/bb/forums/attachments/164-168-1991-1995/150432d1252111089-1991-164s-coolant-temp-sensor-question-p1010001.jpg&imgrefurl=http://www.alfabb.com/bb/forums/164-168-1991-1995/155897-1991-164s-coolant-temp-sensor-question.html&usg=__GJL-KtiSVX6NTOW5hyJzBkX4WGU=&h=480&w=640&sz=62&hl=en&start=1&um=1&tbnid=nYq107EGipkSxM:&tbnh=103&tbnw=137&prev=/images%3Fq%3Dtemp%2Bsensor%2Bjumper%2Bwire%26hl%3D en%26um%3D1

//2000CAYukon

hey man thanks for all the help once again.. i understand it all now.. i did however try and trace the wires down and this is what i found.. the conector has to black wires and one yellow wire. . the yellow wire is cut off and and the two black wires are in the connector.. as far as i could tell i did not have any voltage at either pin and the yellow wire did not have any either.. one of the black wires is run out side of the wire bundle and around behind the radiator resivoir.. and thats as far as i can see it.. the other black wire is in the bundle have not cut it apart yet to see where it goes.. any ideas.. where is the ecm on this type of truck.. thanks