serious IAT issue

LudoN54

Specialist
Mar 9, 2020
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Hi,

experiencing IAT issue
it seems that it goes way too high( 212f)
got 2F0C Code, which is related to IAT sensor, tried to clean, and change it, but still same issue.

mods : BMS DCI, MMP downpipe, custom tune

i live in the caribbean so ambient is often high ( 86 and more)

you will find here some logs =>https://datazap.me/u/ludovic-poviac/...og=0&data=3-21

can someone help with this ?
 

martymil

Major General
Sep 6, 2017
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Yes your running way to rich your afr's are in the 10's which is not unsafe but will cost you in extra heat

Get a better ic as it look like your running the stock one
 

LudoN54

Specialist
Mar 9, 2020
53
13
0
Yes your running way to rich your afr's are in the 10's which is not unsafe but will cost you in extra heat

Get a better ic as it look like your running the stock one
i agree about the intercooler...but that's not the main isssue as one of my friend with exact same setup and tune is seeing 162f when i'm seeing 220...

by the way, i already have a 7.5 stepped VRSF that i DIDN'T install yet because of this issue
 

LudoN54

Specialist
Mar 9, 2020
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13
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10.8 afr's is way to rich and which is not unsafe but will cause extra heat in your turbos which will see your iat's soar especially in hot climates as I live in one myself, get a better ic and raise your afr's to 11.8

Here is a log using a decent ic in 100f ambient temps


totally agree with you, but did you look at my log ? it just doesn't look like just a FMIC issue


Capture d’écran 2020-03-21 à 16.26.07.png

Capture d’écran 2020-03-21 à 16.25.59.png



Capture d’écran 2020-03-21 à 16.25.50.png

Capture d’écran 2020-03-21 à 16.24.56.png
 

martymil

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it might have a temp sensor issue in high iat's but if you look before it drops and when it picks up again if you drew a line between the two points it would be right.

If your worried change the map sensor as that is what the issue would be if any with the iat drop only
 
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LudoN54

Specialist
Mar 9, 2020
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it might have a temp sensor issue in high iat's but if you look before it drops and when it picks up again if you drew a line between the two points it would be right.

If your worried change the map sensor as that is what the issue would be if any with the iat drop only

as i said before...Tmap sensor is brand new
maybe the wiring ?
 

martymil

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You said you changed it but did not say new but it could be wiring.

Once you get the iat's under control I doubt you will see the issue again.

You need to get those iat's under control pronto as its not healthy for longevity of your motor and turbos
 

Asbjorn

Lieutenant
Mar 10, 2018
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European, based in China
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Timing is low because of the high IAT

unfortunately, don’t have logs from my friend’s car

There's no timing at any temperature it seems.

When I ran the undersized 7in fmic (def not recommended) I had very different timing at 120F and +160F. Yours seems to be zero or negative at any temperature.


Try and log coolant and oil temp as well.

Anyway are you sure this isn't something simple such as a dirty / covered fmic? Remember to check behind it as well, as air needs to be able to escape.

Anyhow you have a code, so it's more likely related to that. Maybe there's resistance / worn connection/wire somewhere causing the sensor to read high and disconnect periodically. No experience, just guessing.
 

LudoN54

Specialist
Mar 9, 2020
53
13
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There's no timing at any temperature it seems.

When I ran the undersized 7in fmic (def not recommended) I had very different timing at 120F and +160F. Yours seems to be zero or negative at any temperature.


Try and log coolant and oil temp as well.

Anyway are you sure this isn't something simple such as a dirty / covered fmic? Remember to check behind it as well, as air needs to be able to escape.

Anyhow you have a code, so it's more likely related to that. Maybe there's resistance / worn connection/wire somewhere causing the sensor to read high and disconnect periodically. No experience, just guessing.

on this log, was using mhd stage 2, which is supposed to have some serious timing...what could affect timing ?
 

martymil

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The higher the ait's the lower the timing, from memory timing starts to get pulled at 126f.

The higher the temp the less you get until in goes to none or goes negative in extreme cases like yours. Never seen this extreme as the first step in any build we change the ic as it's absolute rubbish anything other than stock boost levels as its not designed for anything except cold weather like in germany
 

iminhell1

Sergeant
Jun 17, 2018
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Different line of thought,


Check and make sure both wastegate actuators work correctly, hold vacuum, move the flapper, etc.
Being that the system can not tell you if each turbo is working and if they are doing equal work, I would venture a guess that right now one is doing most all the work. EVEN though the logs don't reflect this fully. But if you where to compare yours to a known good setup you'd probably spot the difference in wgdc right away.


So target boost is say 18psi.
One gate is working one is not.
So one gate has to be closed more to meet target and the other is wide open.
That means the gates closed one is working harder, making more boost and heating the air more than should be. While the other just does much of nothing.
 

martymil

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Sep 6, 2017
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Highly doubt his waste gates aren't working properly, his wastegate duty cycle on par and not that high and his boost would not meet target at that psi if they weren't working properly on stock turbos.

It all looks good in that sense