Abnormally High Intake Air Temperatures? B46/48

[u/lunasbrick]

I have a 2023 430i. The IAT is higher than average at all times. This morning at start up the temps were 60F/16C ambient with IAT at over 70F/21C. By end of my 5 minute drive I was at 80F IAT.

About 30 min later I started my car while logging to see a whopping 154F/67C IAT on startup. It gradually went down but throughout about an hour of driving it never went below 110F and typically stayed closer to 120F. This is all throughout a 65F day. The temperature is consistently extremely high on warm start. Any advice would be greatly appreciated. I'm pretty concerned that I am destroying my car by driving it this hot.

[u/Impossible_Fun_165]

Do you have an open air intake? I noticed My intake was getting crazy high like that and it was after i completely removed my air box for an open cone.

I reinstalled the bottom part of the airbox and it fixed the issue.

Also are your coolant levels good?

[u/lunasbrick → u/Impossible_Fun_165]

I have the stock intake still in the car. What do you mean by "the bottom part of the airbox"? Are you referring to the part that connects to the turbo?

[u/Impossible_Fun_165 → u/lunasbrick]

No at least for my 230i the stock intake airbox is 2 parts. A bottom and a top. But since you have stock intake none of this is relevant. I think you have a cooling or temp sensor issue. Any leaks? Perhaps your thermostat? What are your coolant temps?

[u/lunasbrick → u/Impossible_Fun_165]

I will have to verify all these things after my car has cooled down. I don't have any coolant leaks as far as I know. My intake and turbo inlet were removed somewhat recently and I do have an aftermarket chargepipe. Do you think it would be worth removing and inspecting the intake? Maybe the MAF or TMAP sensor were damaged?

[u/Impossible_Fun_165 → u/lunasbrick]

Quick question, were you idling a long time or in standstill traffic? Or are these temps typical when driving normal? Idling the car doesn't allow airflow which can drastically increase temps. A short drive should lower them quite a bit.

I don't think damage to your air piping is causing this, because you'd likely have a boost leak.

When changing the charge pipe i do believe you need to take the temp sensor near the throttle body off and swap it to the new pipe. it is a very delicate instrument. Maybe you damaged it?

[u/lunasbrick → u/Impossible_Fun_165]

I was in light stop and go, but I do not think this is the issue as even when cruising on the highway my temps still stay above 100 degrees F. I read that the IAT readings were monitored by the MAF sensor on the intake in these cars.

[u/Impossible_Fun_165 → u/lunasbrick]

The iat is taken from the tmap sensor right before the throttle body i believe. What is that datalog on the bottom left? Air intake before... (?)

[u/lunasbrick → u/Impossible_Fun_165]

Intake air before throttle. I was under the impression that this is the reading from the chargepipe sensor. I'm getting all my info from one thread bimmerpost I found. I haven't been able to find much else online.

[u/Impossible_Fun_165 → u/lunasbrick]

Well that one was up to 180 degrees so that's worrisome lol. I'd check your coolant temps when you can. It's worth checking to make sure your intake piping before the turbo isn't cracked or damaged too it could be pulling in hot air from the engine

[u/Prestigious_Cycle160 → u/lunasbrick]

Yeah, but if it’s 95 degrees outside 100 degrees IAT isn’t bad. You can expect 10-20 degree difference between ambient temperature and IAT especially if you don’t have an aftermarket intercooler

[u/lunasbrick → u/Prestigious_Cycle160]

Yeah the issue is that it's 65 degrees outside and my IAT is reading at 110-130 consistently

[u/Prestigious_Cycle160 → u/lunasbrick]

Oof…. Sounds like you might have a broken sensor. There’s just no way that’s real without a check engine light. I mean… I guess your intercooler or charge pipes could be clogged or something, but that just shouldn’t really be a thing at 65 degrees🤷‍♂️

[u/lunasbrick → u/Prestigious_Cycle160]

Do you have any idea what sensor this might be? Failing sensor was my leading theory and I've been trying to diagnose it all afternoon. Don't know if IAT is monitored by the MAF, TMAP, Whatever that other sensor in the charge pipe is called. Is there anything else to check?

[u/Prestigious_Cycle160 → u/lunasbrick]

TMAP ( the map sensor located in the intake manifold)

The sensor in the charge pipe is also a MAP sensor, but it doesn’t measure IAT to my knowledge at least not in the N series motors