I've searched and searched the forum but haven't had any luck finding a thread about pulling code 23 on TBI. Any help would be really appreciated.

Background Info:
I bought my '91 Camaro back in October of '06. Came with a 305 TBI and a cheap *** AutoZone Fram air filter housed in a chrome 14" air cleaner housing (Obviously not stock). I seized the little 305 and swapped it with a 350 TBI. I can't exactly tell you what the 350 came out of because I forgot to grab the number off of the back of the block before we dropped it in. I was told it was pulled out of a Chevy pickup between '89-'95. When we swapped it, everything was identical. The only difference between the blocks were the 5.0L engine stamp and the 5.7L engine stamp. We reused all of my 305 top end parts.

The Problem:
Since I've had it back, I've been pulling a code 23 (Low temperature at manifold air temperature sensor OR Throttle position sensor error) after it has reached operating temperature and stopped at a red light. It's driving me crazy! Neither my Chilton's nor my Haynes show the location of the MAT sensor. I've called local dealerships and they just think I'm on crack. They can't tell me anything about it. I know they come with THERMAC air filter housings and I've heard that the MAT Sensor is located there. I've never pulled a code 23 in my 305. WTF?! What can I do to fix this? Where might the MAT be on a 305 TBI?

Thanks again for any help,

RJ

 

I think I might've been trying to hard with the search. I should have just simply typed in 'Code 23' from the beginning... So I did some reading and it turns out the the MAT and the IAT sensors are the same thing. If so, I have to be what I believe is an IAT sensor because it's sitting next to my throttle body, unplugged with electrical tape around a section of the wiring. I've already tried sticking that inside of the air filter housing and I'm still pulling the code.

Now I'm thinkin' that either sensor is bad or the wiring might have a short (obviously). I'll check it out.

 

That's the one, code 23 is the IAT and can be caused by either the sensor being open, not plugged in, or a break/cut in the wiring.

At room temperature the sensor should be about 3200 ohms in resistance. Lower as it heats up, and higher as it is cooled off.

RBob.

 

Yeah, thanks man. That was it. The IAT sensor is also called an air charge temperature sensor. Code 23 is no more.

 

yea i had a code 23 the past couple days after swapping my motor and i pulled it off my air intake assembly drilled a hole in my open element and plugged her in and now no more code 23 she also runs a lot smoother too....

 

Yeah, I noticed that too. The acceleration feels better as well.

 

agreed... other thing i'm wondering is i was told to run the 305 tbi comp in my car instead on the truck 350 ECM i got with the motor.... is that keeping my engine from performing at its top? cause it has a lot more torque but doesn't seem like it accelerates that much faster than my stock L03 did....

 

To be honest with ya man, I don't know if a 350 running a 305 ECM would cut back on power and torque or vice versa. I mean the sensible thing to do is to run a 350 with the 350 ECM. You know what I mean? I'm probably not the best person to ask when it comes to car computers.