I'm working on smogging my new car, and I can't because of the surging idle. I had the codes checked by my friend's shop and I got 23 (MAT sensor) and code 45 (rich exhaust). apparently the rich exhaust can be caused by various fuel delivery problems, which i don't think is the case, because the fuel filter looks new, and the car operstas fine at everything except idle/very light throttle. hwoever, it also looks like code 45 can be caused by defective TPS and O2 sensor, but i didnt get a code for the TPS, so i will assume its the O2 sensor. Also, the car is wired so the fan is always on, and the temperature gauge always is in the red, and my friend thinks that the fan being always on is making the car think the engine is cold, also causing the rich condition

any takes on this situation? i'm going to disengage the permanent fan, replace cololant temp sensor, MAT sensor and O2 and then go from there. any sugestions?

also, the AIR tube to the cat is not connected, could this be causing a problem also? there is a jsut a hole in the cat where it should go, and the tube from the exhaust manifolds ends right before the hole, so could it be sucking in cold air and throwing a code?

thanks a lot guys!

 

The MAT sensor can aid in your problem as well as the CTS sensor and 02 sensor. The TPS sensor can be flakey without throwing a SES light. It needs to be checked with voltmeter if the other 3 don't cure your problem. The fan won't cause it. A lot of us have are fan hardwired on because they kick on to late to do any good. Air tube in the cat may effect the emmissions some but it is not causing your too rich problem or SES lights. By temp gauge always in the red do you mean that its over in the 260+ range. Is it that way when you start the car or does it actually overheat. The gauge uses the temp sensor by the number 1 spark plug. The computer uses the one in the intake by the thermostat.