Air Intake Sensor registering High Temperature around 42 degree
 

Hi,

Please I have a certain inquiry for my Car,

W203 2005 the Intake Temperature sensor is registering high Temperature reading (around 42 degree when idle) outside temperature is around 22 degree.
The Engine Check light is On and the ECU is registering high fuel mixture, how to solve this issue.

I Replaced the IAT sensor with another one same issue, is their unmetered Air entering the engine, how to diagnose it.

The car when idle the supercharger bypass valve remain open and there is no boost. The 42oC you are reading is normal because the engine working like an N/A, sucking air which gets hot from the engine bay temperature. The intercooler start working only when the car is moving and under boost. Don't forget that the IC is air to air. If you log the IAT readings on a hot summer day you will see temperature on idle up to 50oC and on high load even up to 60oC. When I have change the crank pulley and spining the supercharger up to 20.000rpm with the OEM IC I log IAT up to 70oC. Changing the IC with an aftermarket the IAT at high load was up to 50oC. I solve the problem with an intercooler water spray. Till then on a hot summer day of 38oC I see IAT at 42oC under heavy load. You can check on post #6 here https://mbworld.org/forums/performan...5-porting.html
Which code give you check engine light?

Thank you GOGO for your reply,

really helpful,
The real problem that I am facing is that when the car is HOT and you try to start it, the engine shakes and in some cases shuts down,
But once started it runs normal,

Also when the car is cold (started for about 2 min) and you drive a hesitation is sensed if you are going up a small hill (the car hesitates while accelerating),

I don't know exactly the engine code I have to pass it again to my mechanic,
But on the scan it is giving rich Mixture (the MAF + Air Filter + Automatic transmission OIL + filter + Fuel Filter have been changed and same issue)

Please can you advice,
It is becoming a hopeless job,

Can you tell your mechanic to replace the first O2 sensor with a used one that is working. This sensor is controling the Air/fuel ratio from the reading that he takes through the exhaust manifold. After that you can check the fuel pressure and also change the fuel injectors with used one that are working and check yours. If the issue is still there and you have change all the fuel system compenents, I would make SCN to the ECU. It can be done only via an offficial dealer. In Greece it cost 40€.