air intake sensor

[fordF250]

What does happen if this sensor goes bad? also should the sensor be inside the the black boot going to the turbo? I have a napa 6637 filter and the sensor is in the tube right behind it.

[1Dieselman]

Don't know what would happen if goes bad, may have to do with injection timing more than anything. I believe that most just zip tie it to the inner fender near the filter like I did on mine and several others.

[351fifty]

i just left mine setting by the filter, didnt tie it up or nothing, no idea what its doing to my pcm but hell truck runs great anyway

[fordF250]

well im not sure either, because i was wondering if it being in the tube its sending the wrong temperature to the pcm. but who knows. guess i could just buy a new one and try it out of the tube

[1Dieselman]

I wouldn't put it in the tube between the filter and turbo. If it comes out for some reason it would suck in dirt.

[backwoodsboy]

Originally Posted by fordF250

well im not sure either, because i was wondering if it being in the tube its sending the wrong temperature to the pcm. but who knows. guess i could just buy a new one and try it out of the tube

IAT is just intake air temperature.
There's no compression of air pre turbo, so no heating of air. Attatching it near the filter will theoritically give you the same reading as having it inside the intake tube.

As for if one goes bad,
False high reading will lean out the fuel:air ratio. Hot air is less dense than cold air, so with less 02 pcm will send less fuel to keep stoichiometric ration.
False cold will be the opposite.
No reading, I'm assuming will put PCM into limp mode and use preset parameters for fuel:air ratio.

[madpogue]

^^^^^ That's how it works on a manifold-injected engine. But what exactly does fuel-air ratio even mean with a DI diesel engine? Does the PCM adjust injector pulse width the same way as with a gasser? Yeah, I should read the FSM, but it's packed away in the bleeping cold truck.

This is kinda interesting in light of the recent thread about the resistor "chip".