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Old 10-02-2007, 05:59 AM   #1
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Default IAT sensor problem?

I think I have an issue with my IAT sensor  I plugged the laptop in on the way to work this morning as the previous day my car didnít feel as quick, and as the weather is turning I wanted to tune in the cold start enrichments a bit more.

My commute to work is predominantly motorways and with a supercharger and an A/W intercooler the IAT temps would normally rise when at WOT, and then slowly tail off when cruising. After a good 30 mile run the temps would settle around 30degC.

This morning however I noticed that after 2 miles of driving my IATís had reached 40DegC and were slowly yet steadily increasing. I stopped as soon as I could and checked the A/W Intercooler and pump, the cooler was ice cold and the pump was working fine. At this time my IATís shouldíve been at around 15DegC max.

I carried on my journey and the temps slowly kept rising to the point that when I arrived in work MegaTune was displaying temps of 50DecC. At these temps the A/W cooler would be very hot to the touch, yet it was cold.

Iím currently at work and wonít have much daylight when I get home, what things should I check to get the IAT working properly?

Iíve got a spare sensor so Iíll try swopping them out in-case itís failed. I quickly checked the plug and that looked okay Ė no dropped pins?

What else can I check for?

MSnS1 V3 029y, ignition and injection control.

Many thanks
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Old 10-02-2007, 06:40 AM   #2
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Hmm check the grounds and maybe benchtest the sensor, with a multimeter and maybe a glass of water+ a cooking thermometer.
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Old 10-02-2007, 07:44 AM   #3
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Quote:
Originally Posted by magnamx-5 View Post
Hmm check the grounds and maybe benchtest the sensor, with a multimeter and maybe a glass of water+ a cooking thermometer.
figured it's either faulty grounds or a kaput sensor , it's a nice dry day today aswell, really wish I wasn't stuck in work then I can get the damn thing fixed!

Oh one more thing, ISTR my coolant signal is no longer steady, it jitters about a tad. never used to.

it's gonna be the grounds isn't it!
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Old 10-02-2007, 09:46 AM   #4
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If you have one or more sensors reading funny then it probably going to be your grounds. If that doesn't fix it the AIT sensor must be going out. It's not like the firmware just changes all of a sudden to read the sensor different so i don't see how there could be anything else that would affect it. I say check the resistance of the sensor while it's still installed for the heck of it and clean your grounds.
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Old 10-03-2007, 05:23 AM   #5
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I think I've sussed the problem, and it's not grounds...!

If you saw my previous thread on the IAC valve, I figured out the problem with that was it's coolant feed line was blocked, this mean the unit never got that hot and kept the wax valve open.

now it has a good supply of coolant the dummy throttle body which my IAT sensor is bolted in gets VERY hot, This in turn really heats up the sensor (to the point where you can't really touch the sensor.

The job for friday is to relocate my IAT sensor.
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