Engine Coolant Sensor unplugged?

Yes, the ECT is used to help set the fuel mixture. If it doesn't sense the coolant temperature correctly, it will not feed the computer the right info to set the correct air/fuel ratio.

Absolutely. Ford is cheap and if they could get away without having a working ECT, they would have done it.

Normally the ECT lives in the hot water feed tubes for the heater. Someone may have had a bad ECT and couldn't get the old one out, so they plugged the new one in and tied it up out of the way.

When you plug the ECT back in, dump the codes. Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.

See http://www.troublecodes.net/Ford/
OR
See http://www.dalidesign.com/hbook/eectest.html for more descriptive help
OR
See http://www.mustangworks.com/articles/electronics/eec-iv_codes.html

IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.

Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Walmart.

If you get a code 21 when you dump the codes, the ECT is likely to be defective. Note that that if the outside air temp is below 50 degrees F that the test for the ECT can be in error.

or someone thought they were getting some benefit performance wise - with the ECT not relaying a signal of hot coolant flowing, the mixture would stay on the rich side (i dont have 1% the grasp of the puter stuff that JR does, so i will let him answer whether that sounds plausable or not). im not saying that would work, by any means - only that someone may have thought it would.

good luck.

Hey i took mine out and replaced it w/ the autometer one for my autometer gauge and never hooked up the stock wire to anything. I asked this before and somebody said the computer does NOT use the ECT for anything. If this is soo please clarify... maybe this is why I get bad mileage.

Would you have a reccomendation for a spot to put it in if I do need to hook it up b/c my autometer is in the stock location at the front of in the intake manifold.

evn_05 said:

Hey i took mine out and replaced it w/ the autometer one for my autometer gauge and never hooked up the stock wire to anything. I asked this before and somebody said the computer does NOT use the ECT for anything. If this is soo please clarify... maybe this is why I get bad mileage.

Would you have a reccomendation for a spot to put it in if I do need to hook it up b/c my autometer is in the stock location at the front of in the intake manifold.

Click to expand...

you have the two coolant sensors/senders confused. the ECT (in the pic) is used by the computer to tell it how warm the coolant is. the gauge sender (located to the driver side and slightly behind the dizzy) is for the gauge only. that is the one you remove for an aftermarket gauge. one can use another source for the stock gauge, if wishing to retains its function (dont use a Tee fitting). post if interested in other locations. the front stock gauge sender location is the most accurate. DO hook your ECT back up if it is removed.

good luck.