2005 S Type Intake Air (IAT) Sensor Location
#1
02-23-2010, 02:03 PM
Guest
Posts: n/a
2005 S Type Intake Air (IAT) Sensor Location
I recently purchased a device for increasing mileage and horsepower. The directions are very generic. The device is a small resistor with a single bare wire on each end and instructs to insert each end into the two IAT sensor contacts.
My difficulty is that I believe the IAT is integrated into the five-contact Mass Air Flow (MAF) sensor. I have been unable to find a schematic of the sensor to determine where the IAT contact are.
Any help would be greatly appreciated.
My difficulty is that I believe the IAT is integrated into the five-contact Mass Air Flow (MAF) sensor. I have been unable to find a schematic of the sensor to determine where the IAT contact are.
Any help would be greatly appreciated.
#2
02-23-2010, 04:30 PM
Senior Member
First suggestion (no offense intended) is to return this device for a refund. Sounds like it is just a resistor that, when put in parallel with the air temperature senor, will simply reduce the sensor's output voltage and so, the value that the ECU uses for that function in determining air/fuel ratio. Or, if used instead of the IAT, it simply makes the ECU think that the temperature is some fixed value regardless of what the incoming air temp really is.
I don't know whether the Jag's IAT sensor is a positive or negative coefficient thermistor, nor do I know the resistance value of this add-on, so don't know whether this will skew the temperature higher or lower than reality... but it just makes the temperature read by the ECU plain wrong.
How this will increase mileage or horsepower is anybody's guess (more likely make the engine run like crap and perhaps the A/F ratio too lean, causing damage) and is just the seller's way to get at your hard earned money. If it DOES result in leaning out the A/F mixture, this could increase your mileage marginally; but, due to higher knock rate as the mixture leans, the knock sensors will end up retarding timing and REDUCING horsepower... Today's engines already run on the edge of too lean, to meet emissions requirements. If, instead, it richens the mixture, you may get a bit more power at the expense of mileage, perhaps too much emissions to pass testing and premature damage to the catalytic converters. I'm afraid you can't have both. The seller knows this too.
Keep in mind, that this device is simply a resistor that costs about five cents, and is resold as a 'power and mileage chip' for over $20. Pure voodoo!
If you are hell bent on installing it (and I'd recommend NOT, this really is snake oil that could be damaging), then electrical diagrams for most Jags are available for download here: http://www.captainjaguarscathouse.co..._Reference.htm
Good luck!
I don't know whether the Jag's IAT sensor is a positive or negative coefficient thermistor, nor do I know the resistance value of this add-on, so don't know whether this will skew the temperature higher or lower than reality... but it just makes the temperature read by the ECU plain wrong.
How this will increase mileage or horsepower is anybody's guess (more likely make the engine run like crap and perhaps the A/F ratio too lean, causing damage) and is just the seller's way to get at your hard earned money. If it DOES result in leaning out the A/F mixture, this could increase your mileage marginally; but, due to higher knock rate as the mixture leans, the knock sensors will end up retarding timing and REDUCING horsepower... Today's engines already run on the edge of too lean, to meet emissions requirements. If, instead, it richens the mixture, you may get a bit more power at the expense of mileage, perhaps too much emissions to pass testing and premature damage to the catalytic converters. I'm afraid you can't have both. The seller knows this too.
Keep in mind, that this device is simply a resistor that costs about five cents, and is resold as a 'power and mileage chip' for over $20. Pure voodoo!
If you are hell bent on installing it (and I'd recommend NOT, this really is snake oil that could be damaging), then electrical diagrams for most Jags are available for download here: http://www.captainjaguarscathouse.co..._Reference.htm
Good luck!
Last edited by QuadManiac; 02-23-2010 at 05:21 PM.
#3
03-02-2010, 06:53 AM
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