little history...since i've gotten the car ('88 Firebird 305 TBI) in september it's always kicked a code 15. told you it was little, lol.

anyways in all seriousness...original coolant temperature sensor was corroded (coolant type) on the outside of the sensor, around the visible threads, but not by the socket part. Took it out, replaced it with a new one. Codes still there. Did a little research and found out about corosion problems, checked the harness, absolutely no corosion. Checked the ECU harness plugs, absolutely nothing.

Figured ok maybe there is a break in the wire. Unpluged the ECU, and put a 12.16V power source at terminal C10 (yellow), and tested it at the CTS harness, got a full 12.16V source, changed the source to terminal A11 (black), tested CTS harness, and got a full 12.16V source. There is absolutely no loss along the lines.

Would like to check ohms...how do i do that properly...seems my digital volt meter isn't idiot proof.

Ok, studied the wiring schematics of the ECU, and while my source continues to be wrong half the time, i presume that other things are right until i prove them wrong. Anywas, terminal C10 feeds the intake air temperature sensor, throttle position sensor, MAP sensor, and the coolant temperature sensor. All the other ones have their own return signal to the ECU, and would kick their own codes. I'm very simply getting a code 15. Only thing physically wrong with the car at this moment is the fan switch in the passenger head is bad, and is rusted in there and i'm having difficulty getting it out. I'm hearing others running manual switches so i'm assuming thats not the problem. What can i check next?? I'm running out of threads to read.

 

4got to mention, picked up a doner ECU to try out, and that noticed the CTS problem as well and kicked the code 15.

Car starts, and at normal cold, it will idle high for like 5 minutes, then at 5 minutes, something clicks over, kicks the code (when i reset the ECU it does this), and then sputters for a second, then idles at ~700 RPMs, of which i need to kick on the a/c to activate the fan so i think it spikes to ~800 RPMs, nothing serious...just at 5 minutes it clicks over and goes down significantly (closed loop??).

Anyways, if in the first 10-15 minutes i step on the gas, it has the fuel injection quick responsive throttle. After 20 or so, it acts almost like a carbeurator and i step on the gas quickly and it's like i'm closeing all the air off from the engine and it wants to die, but will fight it's hardest to stay alive, and eventually come back to steady idle...just a couple more details that might prove useful.

 

anybody?