Any Advantage To This?............

[JAG1]

I heard of a discussion from a guy that moved his AIT sensor to the intake tube. Any thoughts on doing that mod?

[Mopar1973Man]

I wouldn't suggest it. The fact the grid heaters are controlled by the IAT sensor and being you going to place the IAT before the grid heater now makes the grid heater stay on longer than required. Not to mention the fuel / timing map is designed around that +40*F offset in the manifold so now moving to the intake horn with produce a colder IAT reading and reduce MPG's. The only reason that idea came forward was because of the exhaust brake and cam overlap would coat the sensor in oily residue and possibly offset the IAT readings.

[JAG1]

Sorry Mike it's my fault I didn't clarify. They were talking about putting the AIT in the air box or the tube connected between that and the turbo. Still a bad idea?

[ISX]

Sorry Mike it's my fault I didn't clarify. They were talking about putting the AIT in the air box or the tube connected between that and the turbo. Still a bad idea?

The grid heaters come on when the air is under 60F and all temperatures below that determine how long the grid heater needs to run. So initially the grid heater is turned on based on the IAT reading which if it's been sitting all night and its 0F then that tells the grids to kick on. While they are on, the intake heats up, the IAT obviously sees this and will turn the grids off when the heat reaches a predetermined temperature. If the temperature isn't met, the grid heaters will stay on longer or maybe not even turn off and eventually throw a code. If you put the IAT in the intake tube somewhere, it will never see any kind of heating effects and the grids will initially work, but when the engine is started it will have no idea how long to leave the grid heaters on. I would think the grid heaters must be getting the air to at least 60F since they don't even come on if it is any warmer than that. So yes, bad idea.

[Mopar1973Man]

IAT sensor should be AFTER the grid heater so the ECM knows if the grid heater are coming on or not. (simple version)

[KATOOM]

I'm not sure this is all correct.First.....I believe that the ECM uses the ambient temperature reading and not the IAT readings to determine if the grids cycle. The magic number is 60* outside temp and it doesn't matter if the engine has been running or not either because if the outside temps are 60* or below, the grids still cycle even if you've been driving all day. Ever heard of the grid heater saver? Something an old timer named Harvey created and sold about 7-10 years ago which was supposed to stop all the unnecessary cycling of the grids after the engine has been running. I'm not sure where he is and to bad he no longer sells his kit. Given how little people still customize their 2nd gen truck, those kinda items are far and few, unless you want to make them yourselves. The hard part was tracking down the correct connectors.Second.....The idea in relocating the IAT to somewhere away from the manifold was to stop soot from collecting on the IAT. Something impossible to stop when using an exhaust brake and has even been found on trucks without exhaust brakes. The wet soot eventually causes inaccurate IAT readings and if cleaning it doesn't help, the expensive little part needs to be replaced. Some have moved it to the intake horn by drilling and tapping, and some moved it all the way to the airbox to try and keep it clean. I would think that the airhorn would be the better choice of the two since you'll get more accurate intake air temps as the hot turbo air has run through the cooler. Putting it anywhere before the turbo would result in nothing but COLD air all the time. Really I remember this idea was only attempted by a few and I couldn't say what the outcome was. Yes, the IAT would not receive the same readings. And the new lower temperatures the IAT recognized would cause the engine to run richer. Essentially, you may end up with a little more fueling and a little less fuel mileage. Given how the IAT can be completely covered in black wet soot, I still think the concept is worth exploring.

[Mopar1973Man]

Little more secret to the IAT sensor. Even if you fool the ECM to seeing 143*F grid heaters with still be active post start. I though this was because of the ECM seeing the cold coolant tempaertures. Well during my testing I found the grid heater can still be active even with coolant temperatures of 170-195*F and Iat is still locked at 143*F the only thing left that can see temperature on my truck is the battery temp sensor.But as for moving the IAT up in the air horn I highly suggest against it because of the sole reason the ECM is programmed for the factor of the pre-heated manifold coolant passage that is near the IAT sensor.

[KATOOM]

But Mike, what harm would it cause just because the ECM is programmed for that factor? If the ECM really was recognizing what heat the grid heaters are creating then why isn't there a code for when the grids stopped working?.....but yet the ECM still thinks they are?Maybe this deserves asking around if anyone has or still has a relocated IAT. :)And you said that there's nothing else to read temperature. Does your truck not have a outside temp sensor in front of the radiator? I know that there's trucks without the overhead display but does that mean they also dont have the outside temp sensor? Just curious.