0021 code with ecm link help!!!

[ShaneShane2510]

Okay guys, i HAVE LOOKED ALL OVER AND HAVE DONE RESEARCH AND I STILL CANNOT FIND WHAT IS GOING ON!!!! so i just swapped a built motor into my 90 talon. The wire harness is a 90 converted to a 91.. the previous owner did it. so heres my problem. i put in ecm link and when i first start up my car its starts really hard, and when it gets to running, after about a minute ecm link tells me the temp is like 300 degrees...but the motor is clearly not that hot. it is also throwing 0021 code. my wideband tells me it runs to about 13..1ish on the rich side at idle. im at a total loss. any help would be much appreciated!

 

[eclipsyco]

Hi! Can you post a log file?
Seems like the best place to start troubleshooting.

 

[steve]

so heres my problem. i put in ecm link and when i first start up my car its starts really hard, and when it gets to running, after about a minute ecm link tells me the temp is like 300 degrees...but the motor is clearly not that hot. it is also throwing 0021 code.

Fault code 21 is the Engine Coolant Temp Sensor which makes sense if your is reading 300F. The ECT sensor is a NTC thermocouple so the resistance drops as the sensor heats. In you case it sounds like it's shorted to ground. When the wiring/sensor is open the ECU read -76F or something like that.

 

[Colt4G63 also]

Steve is correct as usual, the only thing I would add is that the coolant sensor input is pin 20 (yellow/green) at the ECU.

http://www.dsmlink.com/images/forums/1GECUPinout.pdf

 

[ShaneShane2510]

okay that makes sense steve, do you have any idea were it might be shorted? i did order a new one too, it will be in on monday.

 

[steve]

okay that makes sense steve, do you have any idea were it might be shorted? i did order a new one too, it will be in on monday.

Disconnect the sensor and measure it's resistance. Disconnect the ECU too and measure the resistance of wire in the harness to ground.

I couldn't begin to guess where the problem is, you'll have to do some diagnosis and perhaps start digging into the harness.

It's tough to work on cars and not get your hands dirty.