Engine/Transmission (1998.5 - 2002) IAT specs

[BMote]

Am wondering what I should be having for IAT temperature? I ran genisys obd tool and noted engine temp held at 180 while IAT temp was 102-104 F.

Don't know what it should be but this seems high. Temp outside today is about 50F, and I thought intercooler's job was to cool intake air. Any thought's what gives here?



2001 w250 auto trans, reg cab long box, step cap Oo

 

[JR2]

The IAT is acutually measuring the temp of your air post turbo, so your numbers are about right. At least they are in line with what I have seen before. Some folks have moved the sensor to the airbox making the ECM think its getting cooler air, this causes the ecm to add a bit of fuel and I belive some timing to the mix. Reports of a 5 hp increase have been seen. Not very usefull for daily driving but for dyno competitions it may be worth it.

 

[nps]

BMote,



Was the engine running or off? If running, your numbers sound high - the IAT should see temps 10-20 above ambient temps. If you just shut down, then the intake will heat toward the engine temps.



If the engine was running, were the heater grids cycling on and off? Generally you can tell by the alt pulling down and the headlights dimming.



If the heater grids were not cycling, and the engine was running, then were you moving? Where's your air intake - any mods? You could be picking up underhood air that is already pre-heated if you are at a stop.



50 degrees above ambient temps do seem a bit high for the intake air, but 100 degrees is about the optimum temp for the intake. So no real problem unless the 50 degree differential remains when the outside air is 100 degrees.



Sorry for more questions than answers, but there are many variables at play.

 

[BMote]

BMote,



Was the engine running or off? If running, your numbers sound high - the IAT should see temps 10-20 above ambient temps. If you just shut down, then the intake will heat toward the engine temps.



Engine was running and warmed up. At idle iat temp was 104, driving at 30mph down the road IAT temp held at 100-012.



If the engine was running, were the heater grids cycling on and off? Generally you can tell by the alt pulling down and the headlights dimming.



Heater grids not cycling. Totally warmed up, engine coolant thermostat opened up at 180.



If the heater grids were not cycling, and the engine was running, then were you moving? Where's your air intake - any mods? You could be picking up underhood air that is already pre-heated if you are at a stop.



50 degrees above ambient temps do seem a bit high for the intake air, but 100 degrees is about the optimum temp for the intake. So no real problem unless the 50 degree differential remains when the outside air is 100 degrees.



Sorry for more questions than answers, but there are many variables at play.

Thanks for questions, but would appear not to be a real problem here.

 

[WestTN]

Intake air temp under running conditions depends on boost pressure and air flow through the cooler among other things.