so i just did an engine swap in my 94 integra rs i put in a gsr and my temp wont read my homie said just buy a temp guage and use that one also my check engine light comes on after about a mile of driving it but everything seems fine need help thanx

 

you know what my temp gauge does not read either...it will say that it is cold until it gets hot enough and then will jump up past the half way point i saw this when i had low coolant in my car but then i put some more in and now it never reads...when i had low coolant it would just get hot of course and it would read after it got to hot and then would read all over the gauge but now that i added coolant it doesnt even move from down by the Low temp part of it and never will

 

See what code its throwing. Its probably the coolant temp sensor.

 

Check the sensor for the gauge, it is the 1 wire sensor right below the distributor cap. When my gauge started acting up, it was because the wire was loose on the sensor.