IAT sensor failure? Is it common?
Thread Starter
Joined: May 2004
Posts: 519
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From: San Pedro, California
IAT sensor failure? Is it common?
OK so now that I have my SMIC issues out of the way with no kids underwear blockage in the end tank, the temps are down but I'm still getting heat soaked badly. I'm seeing my IAT readings all over the map now, like it will be 50 and then drop suddenly within two seconds down to 42, and then fly back up again. I'm thinking that maybe the sensor has failed?
I need to do this quickly before thursday, is it common for this sensor to fail and where can I get one? I do not plan to relocate it for now.
I need to do this quickly before thursday, is it common for this sensor to fail and where can I get one? I do not plan to relocate it for now.
I’m not sure on failure rate, but I know they’re slow to react. Upgrade it to a fast reacting air temp sensor. You’ll need to put a new plug on that part of the harness but it’s pretty easy.
Mine failed with 54k original miles on it. Threw a code and everything (stock ECU).
I would replace it to be sure. Only the stock ECU is smart enough to diagnose failed sensors, with the exception of something unplugged showing up on a PFC. So it's a guessing game to some extent.
If you change to fast acting sensor you need to check the AFR's. They will change and could require some retuning.
I would replace it to be sure. Only the stock ECU is smart enough to diagnose failed sensors, with the exception of something unplugged showing up on a PFC. So it's a guessing game to some extent.
If you change to fast acting sensor you need to check the AFR's. They will change and could require some retuning.
Joined: Mar 2001
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From: https://www2.mazda.com/en/100th/
at the dealership we used to sell a fair amount of these sensors, they do go bad. typically the CEL only came on for the IAT, ECT or the EGR switch. occasionally you'd get surprised with a turbo solenoid or something, but pretty rare. the CAS codes meant you need a harness
Mine failed with 54k original miles on it. Threw a code and everything (stock ECU).
I would replace it to be sure. Only the stock ECU is smart enough to diagnose failed sensors, with the exception of something unplugged showing up on a PFC. So it's a guessing game to some extent.
If you change to fast acting sensor you need to check the AFR's. They will change and could require some retuning.
I would replace it to be sure. Only the stock ECU is smart enough to diagnose failed sensors, with the exception of something unplugged showing up on a PFC. So it's a guessing game to some extent.
If you change to fast acting sensor you need to check the AFR's. They will change and could require some retuning.
Thread Starter
Joined: May 2004
Posts: 519
Likes: 28
From: San Pedro, California
Oh I have an adaptronic select...so I don't think there is any code to see if there is a malfunction. I'll just replace the sensor anyway...can it be done without removing the UIM? And if it has to come off, what parts should I prepare before doing it (gasket, etc.)?
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Joined: Sep 2017
Posts: 75
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From: Ojai, CA
Last time I drove my car in the canyon, I noticed my IAT reading from PFC Commander sometimes just doesn't make sense. It could show -1°, -2°. I pulled over and it went back to normal (42°C). But then it happened again, and I had to restart my engine to get normal reading. I worry if my fuel injection can go differently if the ECU does count in that abnormal IAT reading. But I didn't feel any difference in driving when it does that.
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Option #2...Reach under and unplug the connector, leave old sensor in place, cut and solder an extension for the two-wire connector and relocate a fast reacting sensor just downstream of the IC. Less heat soak, better real-time readings and no pulling the UIM.
Last edited by Sgtblue; May 21, 2018 at 06:22 AM.
I see them go bad all the time. Replace it with a fast acting sensor and tune accordingly. The stock sensor is just too slow to respond: You're in traffic and car heat soaks. Traffic opens up and you get on it. Ecu thinks intake temps are still through the roof and pulls fuel according to the temperature correction on the fuel map. You detonate and blow up.
Thread Starter
Joined: May 2004
Posts: 519
Likes: 28
From: San Pedro, California
I see them go bad all the time. Replace it with a fast acting sensor and tune accordingly. The stock sensor is just too slow to respond: You're in traffic and car heat soaks. Traffic opens up and you get on it. Ecu thinks intake temps are still through the roof and pulls fuel according to the temperature correction on the fuel map. You detonate and blow up.
https://lms-efi-llc.myshopify.com/co...x-7-direct-fit
Skeese
Joined: Nov 2011
Posts: 842
Likes: 115
From: South Orange County, CA
The sensor sold by LMS EFI is a direct fit into the FD UIM and can be orderes with a PnP harness to adapt it to the oem IAT plug on the FD harness. This sensor doesnt require a change in the ecu calibration as its output is extremely similar to the oem sensor, its just faster.
https://lms-efi-llc.myshopify.com/co...x-7-direct-fit
Skeese
https://lms-efi-llc.myshopify.com/co...x-7-direct-fit
Skeese
Joined: Nov 2011
Posts: 842
Likes: 115
From: South Orange County, CA
Bummer then.
I run a PFC normally but have to return to the stock ECM every two years for CA emissions inspection. Would like to use the faster sensor, but I don't want to have to pull my UIM every time. Bad enough I have to swap ECM's...
I run a PFC normally but have to return to the stock ECM every two years for CA emissions inspection. Would like to use the faster sensor, but I don't want to have to pull my UIM every time. Bad enough I have to swap ECM's...
Skeese
Thread Starter
Joined: May 2004
Posts: 519
Likes: 28
From: San Pedro, California
I just picked up a new stock IAT sensor locally. I'm just going to swap this in for now because I need to track my car this weekend, I'll worry about the fast acting one later
Last edited by mkiv98; May 21, 2018 at 06:04 PM.
Thread Starter
Joined: May 2004
Posts: 519
Likes: 28
From: San Pedro, California
Ok I took apart my UIM and found that there is already the wannaspeed PNP harness attached to what the previous owner just told me is a triumph sensor, which he calibrated himself. so it may be tricky for me to swap this out for a stock one if I need to retune yet again.
I don't think I can return the stock IAT sensor, does anyone want it? or should I still try to use it instead of the triumph one?
I don't think I can return the stock IAT sensor, does anyone want it? or should I still try to use it instead of the triumph one?
Thread Starter
Joined: May 2004
Posts: 519
Likes: 28
From: San Pedro, California
I guess I will try to locally source the same triumph sensor...can I just swap a new one in as long as it is the same part? Without having to go through any sort of calibration mess?
Thread Starter
Joined: May 2004
Posts: 519
Likes: 28
From: San Pedro, California
I'm just in a hurry bc I have to be at laguna seca on sunday. For some reason everything likes to break right before track days.
Thread Starter
Joined: May 2004
Posts: 519
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From: San Pedro, California
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