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Old 08-16-2011, 03:14 PM   #1
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Default GM AIT going bad?

My AIT readings are shooting to 100C sporadically. I will be driving along fine and suddenly the car shudders like a lean blip, which is probably what's actually happening but my LC1 is dead right now.

I had the stupid car die at an intersection as the light turned green and I hadn't reacted yet .

I have a log but there isn't much to see besides AIT spiking every once in a while and sometimes pegging at it's max value (~100C) and stalling the car but otherwise working fine. The cage type sensor and wiring appear intact, the element was against the side of the cage facing the throttle body though I didn't think this was a problem.

If I unplug the AIT MS works off the last reported value and the car idles great, I've not driven it like this.

So any thoughts, bad sensor? Anyone else had AIT sensor problems?
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Old 08-16-2011, 03:56 PM   #2
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I had a problem where my AEM AIT would drop to absolute zero about a month after install, turned out one of my wires had a bad solder joint on it.
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Old 08-16-2011, 04:09 PM   #3
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I should add that I did have the CLT sensor flailing a couple days ago during warmup but this happened once and never again. I've not had sensor issues in a couple years of operating the car with the MS but am having tons of issues suddenly.

Last edited by inferno94; 08-18-2011 at 09:33 AM.
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Old 08-18-2011, 12:07 AM   #4
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The car now only returns 16C or 102C for the IAT value regardless of ambient. I have confirmed continuity from the sensor plug all the way to the IAT pin on the db37.

Even though there is no continuity problem the IAT gauge goes from 16C to 102C upon wiggling the MS harness most often causing a stall. If there is a continuity issue in the MS harness I can't replicate it, with an ohm meter attached to each end of the harness and wiggling the crap out of it there is no change in continuity / resistance. The in car wiggling to cause stalling / intermittent power loss can be as simple as turning or going over a manhole cover.

16C is not ambient but the MS is only outputting this value to TS along with 102C. As stated earlier the sensor's resistance varies when you blow warm or cool air on it.
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Old 08-18-2011, 11:09 AM   #5
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If wiggling the wires causes your AIT to change with the wiggling, then the only plausible explanation is you have a bad wire.

If you can't find the bad wire, it's pretty easy to run new ones. Temp sensor is only 2 wires.
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Old 08-18-2011, 11:47 AM   #6
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I agree, this is being made more complicated than it is. If the sensor works (it does according to you), then it's the wire, or the MS. Since wiggling wires = problem, run new ones.
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Old 08-18-2011, 12:18 PM   #7
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Quote:
Originally Posted by Ben View Post
If wiggling the wires causes your AIT to change with the wiggling, then the only plausible explanation is you have a bad wire.

If you can't find the bad wire, it's pretty easy to run new ones. Temp sensor is only 2 wires.
Turns out the plastic case on the db37 was partially pinching a couple wires, the issue went away completely with it removed. I've corrected this and it's working fine now.

Thanks
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Old 08-18-2011, 12:38 PM   #8
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Isn't finding bad wiring fun?

Glad you got it sorted man.
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Old 08-18-2011, 09:40 PM   #9
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im having a similar problem but mine is jumping to 170*F only when ambient temps are below 70*F and only at 2200 and 2500 rpms. above and below that range never has a problem. i wiggled and shook the harness and it didnt change the value.

i ordered a new MS1 3.0 chip from diyautotune. it just got here today so im gonna see if it fixes it.

edit: replaced my chip and my problem went away

Last edited by fastivab6tg25mr; 08-19-2011 at 06:04 PM.
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