Intake air temp showed up as 203F. Normal?

Post by **gnalan** » 31 Jul 2020, 11:54

I tried searching intake air temperature, and nothing showed up. If this has been asked before, can someone point me in the right direction or show me how the search feature works? Plus I'm not sure why the topic posted in all caps when it wasn't written that way.

Like the title says, my IAT was 203F this morning which seems way too high. I don't remember what the coolant temp was when I checked it through VIDA, but every time I've checked the IAT has always shown a higher temp than what the coolant or outside temps were. The outside temp was only 73F.

Is this normal, or does the IAT sensor need to be replaced? Could there be something else causing the reading to be off?

Thank you in advance for your assistance.

Post by **RickHaleParker** » 31 Jul 2020, 15:15

Take the IAT temperature as you start the engine in the morning. When the Turbo and engine are still cold and cannot warm the Intake Air. Reading should be within within 10 degrees of ambient temperature.

Try disconnecting the IAT sensor. See if the reading changes. If it does not most likely a short / open in the sensor wiring or dirty sensor connector.

Post by **gnalan** » 31 Jul 2020, 16:12

The 203F was when I first started it up, and it's the NA version, unfortunately, not the turbo version. It's a B5244S.

I'll check the numbers again in the morning, and post the IAT, coolant, and ambient temps, both with the IAT plugged in and unplugged.

Just for clarification, where on the intake manifold is the IAT located, and is there any other sensors in the same area that I could get it confused with?

Post by **gnalan** » 01 Aug 2020, 10:26

An FYI, for those like myself that didn't know, the IAT is part of the MAF sensor, which I found out looking on YouTube after spending about 30 minutes feeling around on the intake manifold for the sensor and not finding it anywhere.

Before starting the car I forgot to write down the readings, but here's the readings after it warmed up and the radiator fan kicked on, according to VIDA:
Ambient temp 27.14C (80.85F)
Coolant temp 105.57C (222.03F)
Intake air temp 72.94C (163.29F)

This is with the car idling in a garage nose first, and the garage door open at the rear, so the only airflow across the front end, and the radiator, was from the radiator fan.

The intake air temp seems pretty high, for a non-turbo engine, but I could be wrong. Do these numbers look normal? I wasn't able to take the car out for a drive to get any readings to see if the IAT would come down any, unfortunately.

I will check the numbers again, after the car is cooled of completely, to get the cold readings I should have written down before I started it.

Post by **- Pete -** » 01 Aug 2020, 22:44

On turbo‘d P2’s the IAT is not built into the MAF. It is on the outlet side of the intercooler, just before the air goes into the intake plenum (pipe). It is also referred to (on turbo’d cars) as the MAP sensor or BPS (Boost Pressure Sensor).

Your initial indicated temp at MAF seems abnormally high. The second temp you posted seems close enough when up to temp (none of my P2’s are NA). Have you cleaned it? I would avoid using anything but MAF spray & compressed air and make sure you don’t come into contact with any of the innerds.

Post by **RickHaleParker** » 02 Aug 2020, 00:43

Get one of them digital kitchen probe thermometers. Stick the probe in the intake air stream after the MAF. That will give you something to compare the readings to.

Post by **gnalan** » 02 Aug 2020, 00:52

Thank you for the tips. I have not cleaned a MAF sensor before, but I'll give it a try. I'll also see if I can find a thermometer to check the IAT against.

Post by **RickHaleParker** » 02 Aug 2020, 00:59

Quick way to tell if the IAT is in the MAF. Disconnect the MAF see if the IAT reading changes. Yes the car will run with the MAF disconnected.

Post by **jimmy57** » 02 Aug 2020, 08:37

The air preheater hose from the air heater shroud over exhaust heats the air. Disconnect and plug the vacuum hose over to the air cleaner and enjoy a better running car all summer. You might need it in the winter for throttle icing prevention and it has some positive impacts on faster warm up and lower emissions. It has no realized functionality during warm weather (over 50F or thereabouts).

Post by **gnalan** » 02 Aug 2020, 08:44

jimmy57 wrote: ↑02 Aug 2020, 08:37 The air preheater hose from the air heater shroud over exhaust heats the air. Disconnect and plug the vacuum hose over to the air cleaner and enjoy a better running car...

Do you have a pic I can go by so I make sure I'm unhooking the right part(s)?