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Iat Inquiry


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So I am experimenting with my own car to learn how to tune and hopefully develop . I am currently road tuning my car and have all compensation off except iat . I have a roughly 36 to 43 deg C IAT and have set up my iat according to the help file and the HPA course meaning 20C is 0 and every 10 deg over I reduce 2.5 deg meaning 30 would be -2.5 , 40deg would be -5 and so on .  I am finding my car leaning out almost as much as the compensation is . So my question is if my fuel map and mybiat map was correct shouldn't I still have the same lambda ? Like at 3000rpm and -60kpa my target is lambda 1 and I am reaching lambda 1.07 . Shouldn't I still have lambda 1 ?!

 

TIA

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The IAT compensation figures you quote usually work ok for most.  Where is the IAT sensor placed - does it give a good representation of what the air temp in the manifold would be?

Can you explain how better what the problem is; Are you saying when your IAT is close to 20deg then the fuel table is adequately calibrated so the measured lambda follows target well, but when your air temp increases from 20deg then your measured lambda drifts leaner than target?

What fuel and injectors?

 

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The car is Honda civic with a b18c engine obd1 Link PnP I have uploaded the base map . Did all the necessary configurations to run cop , checked timing and adjusted it . I am using pump 100 octane (Europe) and stock injectors as my car is fairly stock besides gear ratios and a intake manifold and throttle body . I am also using the obd1 honda iat sensor which is on the actual intake manifold (planning to go on the cai piping once my new engine is finished)

Rrob I think I checked injector deadtimes but cant remember 100% (have been chasing a lot of stuff) 

Adam I will post a log file once I in front of my computer . But where I am coming from is I am road tuning the car with Iat on . I thought the purpose of the iat compensation is to reduce fuel when its hotter lets say 40/50deg C but still achieve the same lambda target as if it was for example 20/30 defense where it will not be cutting fuel . Am I correct on that thought ?

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20 hours ago, Kanjo` said:

Adam I will post a log file once I in front of my computer . But where I am coming from is I am road tuning the car with Iat on . I thought the purpose of the iat compensation is to reduce fuel when its hotter lets say 40/50deg C but still achieve the same lambda target as if it was for example 20/30 defense where it will not be cutting fuel . Am I correct on that thought ?

Thats correct, but what Im asking is has the fuel table been tuned so that when the IAT is at 20 deg the lambda is close to target?  

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I believe that I am suffering from heat soak as when I am parked fro a little bit I see the IAT going up to +10 degress from when I am driving . I have uploaded 2 logs (VTECtest3+ and cruise test)one that were done before the whole corona virus and I believe that was kinda ok , I know some adjstuments had to be done especially on lift off , which I was planning on doing but started running lean  and the one I did today (log 2020-05-27). I have attached as well my tune .

TIA 

vtechtest3+.llg Honda Civic 92-95 G4+ NA Coils.pclr Log 2020-05-27 7;55;41 pm.llg cruise test.llg

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You have an IAT correction on. It is pulling fuel all the time as per your 05-27 log. 

Is this what you refering to?

 

Also .. an FYI.. your fan seems to be on all the time.. and you've reach 212F on your temp.. 

 

2020-05-27 15_17_17-PCLink Engine Management - C__Users_Remski_Desktop_Downloads_1274824286_HondaCiv.png

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thanks Remski2 for the info , Will check the fans 1st thing tomorrow . See the thing I am asking yes I see that it is pulling fuel as it should but shouln't I still get similar numbers regardless of IAT due to the compensation ? What I mean is that lets say at 3000rpm at -60kpa if I target lambda 1 shouldnt when the iat increases/decreases stay roughly the same due the iat compensation ? Since if its getting hotter its pulling fuel trying to reach lambda 1

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I've had the same problem.. 

IAT correctons would just mess my fueling.. maybe I was removing too much ?

I've zero-ed out the high temp correcton and instead of that I am using IAT Ignition Trim 3D table, pulling more timing the hotter the air gets.

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2 minutes ago, Electredge said:

Remski2, before you made the 3d table was it causing most of the problems at idle and low speeds? 

This is my old table..

So in my case it would kick in when IAT was above 104F.  

If it was a cool day the AFR's would stay pretty much the same and there would be no correction.

 

2020-05-27 19_40_31-PCLink Engine Management - C__Users_Remski_Desktop_Downloads__Vipec_Maps_2020_20.png

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Remsk2, you should look into setting up charge temp table, for IAT sensors that are mounted in the intake manifold it creates a bias that you can setup for ignoring IAT temps under certain circumstances. for ex. low rpm / idle you can have the table only watch ECT and once the rpms pick up and load comes up it can bias the other way. 

hope that helps 

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Thanks for the inputs . See I was thinking of changing the setting on the iat table and see cause once I set 40 deg at -2.5 it gets a lot better . So maybe I have to set that correctly and alter my 0 point to 30 deg (I think that is what Adam was trying to see . I just want to the right steps in the whole learning process 

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9 hours ago, Electredge said:

Remsk2, you should look into setting up charge temp table, for IAT sensors that are mounted in the intake manifold it creates a bias that you can setup for ignoring IAT temps under certain circumstances. for ex. low rpm / idle you can have the table only watch ECT and once the rpms pick up and load comes up it can bias the other way. 

hope that helps 

Is this applicable also on N/A vehicles , to give it a try ?!

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