Problem began at a recent track day. Car had been driving and running great on my do-it-yourself tune. Another LS1 enthusiast was having driveability issues with his tune, so I offered to let him drive my car to to show off my handy work. Of course, that's when Murphy's Law kicked in and made me look like an idiot Started off stalling at idle every now and then. Problem was intermittent; sometimes it was okay, sometimes it would stall. Driveability also seemed to lose its "crispness", especially low speed/light throttle. Symptoms became more frequent over the next few days. No check engine light (yet).

I knew something wasn't right, but babied it until the weekend. Finally got check engine light with codes P0113 and P1111. Scanned it with HP Tuners, and sure enough, IATs were reading -38* and fuel trims were WAY off. Turns out to be a common problem with broken wires to the IAT sensor plug, I cut the wires short and resoldered them to the plug; very simple repair that only took a few minutes to fix. IATs are reading normal, and fuel trims fell right back into line...car drives like a dream again.

Moral of the story...problems don't fix themselves; I should have scanned it right away. The symptoms were obvious before the car threw any codes. I don't know what parameters need to occur to throw the codes, but if I would have scanned it right away, the below zero IATs and crazy fuel trims would have been red flags.

 

Well, yeah, I guess you could have scanned it earlier before it threw the code, but how would you have known where to look?

Interesting you were able to fix the existing plug; the three times I've had to repair the IAT plug it was broken right where the wire went into the plug itself, no room to repair the wire.

Have a good one,
Mike

 

The wires were both broken right at the rubber grommet going into the the plastic plug; I had just enough wire out of each terminal pin to solder wire-to-wire. If it happens again, I'll either need to perform a little surgery on the pins, or get a new pigtail.

The breaks in the wires at that connector seem to be pretty common, and they were causing an intermittent issue, which would normally be difficult to diagnose. However, if I had been logging with the scanner, it would have showed the IATs tanking (and subsequent fuel trim corrections) whenever those driveability issues showed up. Wouldn't have taken too much detective work to figure it out, and would have saved me a week of miserable driving. But, that's what I get for being lazy.

 

I'm having the same problem as well with my '99. Would someone be able to give me an exact location of the sensor so I know where to look? Thank You.

 

Driver's side, forward of the throttle body, just in front of the bellows, IIRC. A 2-wire sensor.

HTH, and have a good one,
Mike

 

just a random thought, im getting those 2 codes as well. i have nitrous on the car also, the n2o tune is a tad rich for safety reasons, but recently ive noticed the car laying down a lot on spray. i wonder if the bad iat is causing a overly rich condition on the spray , so much that its causing some noticeable surge/bog on the up shifts. thanks for the info, as soon as i get home im going to log iat via HPT.

 

I can understand that a constant IAT temp of 38* would throw a code--but what is puzzling is that the IAT table in the computer only adds or subtracts timing to the Hi & Lo octane tables depending on the sensor reading--Can't undestand how that would affect the fuel trims ?