3rd Gen Engine and Drivetrain -> 2003-2007 5.9 liter Engine and drivetrain discussion only. PLEASE, NO HIGH PERFORMANCE DISCUSSION!

can a dirty IAT Sensor cause mileage to drop???

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Old Jun 6, 2007 | 10:41 AM
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Rollin' Smoke's Avatar
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From: LaPorte, TX
can a dirty IAT Sensor cause mileage to drop???

was wondering if that was possible on these trucks. if the sensor has dirt built up on it, that would likely scew the readings. am I correct?

had anyone cleaned one or have a procedure for doing so?

thanks in advance
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Old Jun 6, 2007 | 10:54 AM
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I cleaned mine once with some 91% alcohol on a Q-tip and gently wipping it.

Pete
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Old Jun 6, 2007 | 11:03 AM
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i am not exactly sure where it is located on the CTD.....i am fairly new to them
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Old Jun 6, 2007 | 12:15 PM
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I'm assuming that it's similar to my '05... there's two!
one by the air filter on top of the elbow going down to the turbo. It has 4 wires going to it. Also there is one on top of the intake manifold. This also has 4 wires going to it. This one is near the pressure relief valve & rail pressure sensor.

Both sensor do the same thing. Both are IAT & MAP sensors.
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Old Jun 6, 2007 | 12:21 PM
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I think it's located behind (or post) air filter. If that's the case I don't think it should be getting dirty.
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Old Jun 6, 2007 | 12:44 PM
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From: My head lays down in Murrieta, but the day light hours are spent in San Diego, Ca.
Originally Posted by tesla440
I'm assuming that it's similar to my '05... there's two!
one by the air filter on top of the elbow going down to the turbo. It has 4 wires going to it. Also there is one on top of the intake manifold. This also has 4 wires going to it. This one is near the pressure relief valve & rail pressure sensor.

Both sensor do the same thing. Both are IAT & MAP sensors.
Ummmm, sorry, but no they do not do the same thing. The IAT sensor is the "Intake Air Temperature", which meters the temperature of the air in the intake manifold. Where as the MAP is "Manifold Absolute Pressure" sensor, which meters the pressure of the air in the intake manifold post-turbo.

If the sensor you're talking about is up near the air filter, that will be a MASS sensor, which meters the amount of air flowing into the motor pre-turbo. It doesn't meter air pressure.

Different sensor all together..............
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Old Jun 6, 2007 | 01:13 PM
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From: lyman, utah
i cleaned mine w/ carb cleaner,and it made no difference
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Old Jun 6, 2007 | 01:15 PM
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ctd's dont have a mass air flow sensor. the one at the filter is intake air temp. that's it. just temp of the incoming air.
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Old Jun 6, 2007 | 01:20 PM
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wow, kinda steered up a lot of different answers. know what I know from messing with EFI cars, i pretty much new the one on the intake was the IAT but I just wanted to confirm

now with all that said, can dirt on that sensor effect the mileage or fuel mixture?
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Old Jun 6, 2007 | 01:21 PM
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From: My head lays down in Murrieta, but the day light hours are spent in San Diego, Ca.
If the IAT sensor and or the MAP sensor were dirty, yeah, they could effect mileage. But as stated by johnh, cleaning alone may nothing. If you're in the average already with mpg, cleaning them will NOT give you better mpg. If you see a drastic drop in mileage, dirty sensors might be the culprit. Might just be something else all together.
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Old Jun 6, 2007 | 01:23 PM
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From: My head lays down in Murrieta, but the day light hours are spent in San Diego, Ca.
Originally Posted by dodgezilla04
ctd's dont have a mass air flow sensor. the one at the filter is intake air temp. that's it. just temp of the incoming air.
Thaniks. I know mine doesn't, wasn't too sure about common rails. But I was just to state that the IAT and MAP sensors do not do the same thing.
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Old Jun 6, 2007 | 01:26 PM
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you're absolutely correct that they do not do the same thing. one senses temp, the other senses manifold pressure(boost).

when the engine(coolant) and air(incoming) is cold the electronic units on gassers spray more fuel to help warm up the vehicle faster. if it never senses the warming up of temps, then it will get worse mileage. but I do not know if the CR CTD's do the same thing.
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Old Jun 6, 2007 | 01:30 PM
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Originally Posted by JPR Ram
If the IAT sensor and or the MAP sensor were dirty, yeah, they could effect mileage. But as stated by johnh, cleaning alone may nothing. If you're in the average already with mpg, cleaning them will NOT give you better mpg. If you see a drastic drop in mileage, dirty sensors might be the culprit. Might just be something else all together.
i am not saying that I think I am getting bad mileage because of the sensor being dirty........I was just curious and thought it might get some people's wheels turning. trying to ask something that i have not seen on here before, but I havent been here that long either
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