Ok we had a discussion back on facebook sometime ago about the internal gas law calculation of ecumaster, thats usually leaning out fuel when heat soak occurs idle in traffic and IAT temperatures are going really high e.x. 60 celsius you will see your AFR goes lean and trims go 5-10% up. But also someimtes i noticed even when sensor is not affected by idle heat soak, it also leaning out the AFR when under boost heat.
Many suggested moving the sensor for the idle heatsoak problem, but as a professional tuner with no real say of how the sensor layout is from the factory or from a garage shop.
What was my solution with V2 software and classic ecus, is i would actually make the IAT Fuel Enrichment table to ADD fuel when IAT would show higher temps, and that would work pretty well countering the invisible internal gas law correction.
But now in V3 the IAT fuel enrichment also modifies your AFR target.
Which that screws me bigtime because the table is 2D, and i cant trick the automatic gas law leaning without screwing up my AFR targets. Do you guys find this frustrating ? Or noone has noticed it yet ?
PS: Repeating i dont have a garage so i dont have the tools to start moving around sensors and wiring looms.
And make my IAT theoretical even higher for even more leaning out ?
I make it zero so it always reads exclusively IAT temperature as charge temp otherwise the above problem explained becomes even worse and complicated. You can experiment yourself pretty easy as well. Disable short Fuel trims from your wideband, and on your first warm up to 90c with open hood idling in your garage and IAT’s 25c see the AFR, then Close your hood and wait until intake temp goes to 50-60c.
Watch your AFR to climb up to 15.5-16afr. Then pull the IAT plug off… You will see your AFR comes back at normal range when the IAT temps goes back at Failsafe value at 25C and ~14.5afr , put the plug back again you get the 60c and leaner at 15.5-16 AFR again.
I just explained above what makes it go lean. Perfect gas law doesnt work in real applications. One solution is to move the Iat sensor away from the engine but thats really difficult or impossible in many circumstances. Have you used V3 ? or you just commenting for the first quirk ?
In V3 its a percentage change. i usually put my real Lambda against my Lambda target on the graph, and i saw my Lambda target go richer slowly along with my IAT temps. I took notice when my lambda target also on idle was starting to go richer than my set 1.000
I think everything has been connected to some kind of automatic fuel calculation.
I was also trying to enable fuel pressure delta safety but it wasnt working and, and i have a suspicion that fuel pressure delta channel is not working unless you enable the MAP Referenced + Fuel Pressure Sensor from the main fuel settings menu which attatches to an automatic fuel trim% so any lag or noise in the fuel pressure sensor analog voltage occurs you have to suffer it on this trimming your fuel byitself as well…
thats a little bit uncalled decisions in the software for noob tuning dudes that have no clue whats going on.
Charge temp is not a correction its a mix of CLT and IAT to properly calc the actual cyl charge temp. 0% would be all IAT and 100% would be all CLT based. At idle your charge temp will be about 75-85% CLT based to combat heat soak. As air speed comes up, your CLT heat soak goes down and IAT can be used for charge temp. If you are using IAT only, you are calculating “charge temp” off the wrong value. Charge temp is what the airflow calc is based around so you need to be calculating the correct charge temp.
The onboard description does a good job saying what is does.
”Charge defines the contents of the cylinder after all valves have closed, consisting of the fresh mixture and residual gases. The simplest way to estimate air density is by using IAT. However, this approach doesn’t account for the effect of air heating from the intake manifold and engine components. At lower air flows, air heating becomes more significant. To address this phenomenon, the Charge temperature estimation table was introduced. This table defines the influence of IAT and CLT on charge temperature. A value of 0% means the charge temperature is equal to the IAT sensor reading, while 100% means the charge temperature is equal to the CLT sensor reading.”
I dont think you fully understand how they interact. Charge temp on ZERO will cause the exact problem you are having because you are assuming the CLT temp has no influence on the air as it travels down the manifold runners and enters the cylinder but CLT does affect the final temp. So you can’t just ignore it and set charge temp to 0 then expect it to be stable. Once the engine is warmed up CLT is relatively stable so lets look at the opposite situation, charge temp is 100% (CLT) then the engine will be very rich as the air is hot with less o2 and lean when its colder and denser with more o2. Inversely if its set to 0% then it will have the opposite affect of leaning out when the engine is heat soaked like you describe. Essentially your whole VE table is lean but the 0% charge temp split is adding fuel making appear correct by over compensating until the IAT reached similar temp to the CLT then the true lean VE is becoming apparent. At this point the charge temp table has little to no affect anymore because both temps are similar anyway so your incorrect 0 setting is not affecting it anymore. However the rest of the time AIT < CLT so if the ECU is only using the lower IAT in its fueling calculation it will be adding more fuel than it should because your telling it the charge temp is colder than it actually is and you have then lowered the VE to compensate and make it appear correct again. I hope this makes sense you may have to read it again carefully.
I typically run about 60-70% at idle and light load, tapering down a little as RPM rises and then sloping down to around 10-15% at high load and boost. Maybe you need slightly different values but fundamentally it wont be a lot different.
Ok since you are insisting with the charge temp thing you suggesting it will make the problem even worse… and funny you suggest this because it means you havent tested in real life yourself ever…
IAT at normal operating temp 25C idle IAT at heat Soak 60C…
IAT with charge temp 100% assumes Intake Charge at 90C (CLT equal).
AFR will be even leaner EVERYWHERE… because model assumes 90cHEAT = less oxygen than 60c = less injection time = hence i get LEANER AFR than ideal because air in real life doesnt follow the theory. My problem (everyones problem actually) even in scorching hot intake, air doesnt give a fudge, still wants the same fuel as if intake was 25C.
But why are you guys not comprehending what im writing though ?
You lost me at the first phrase of “Charge temp on ZERO will cause the exact problem you are having” (its like i wasnt desperate enough to mess with edgy values on charge temp table)
High IAT = Smaller Injection from the theoretical inernal Gaw Law calculation
REAL AFR leans from 14.7 up to 15.5-16
Removing the IAT plug to drop IAT from 60Celsius to default failsafe 25C Fixes the problem
Many suggested to move the IAT further up the intake pipe and not inside the Manifold.
i argue its not possible for me when tuning dozens of cars per year. Especially with plug and play adaptors
Problem became worse with V3 because now a 2d IAT enrichment map also alters the lamda Target. So Ideal Gas law leans out my true AFR, if i try making it richer by my old trick now by enriching the injection with higher IAT to counter the internal gas law, the V3 firmware modifies my Lambda Targets as well…|
NO thanks i dont afraid of breaking my car on idle i dont want 15% Lambda target enrichemnt because i got stuck in traffic and got 75C IATs…
That was my intend of the post to mention a quirk on top of a quirk.
Now i cant even correct the problem like i was doing with V2 (ok maybe waste a custom table correction sure…)
@kimbaku, I just mentioned your solution in my post if you bothered reading (not).
You are the one that asked in a sarcastic way “How IAT correction modifies Lambda Target”. I guess you learned something from a guy that doesnt know, weird how it works eh ?
No mate. I set up a custom 3D fuel correction table using (IAT x axis) v (MAP y axis) v (Inj PW % z axis).
Fueling / Corrections / General
Then make: Custom corr 1 x axis = IAT, y axis = MAP, Custom corr condition = Always Active, Custom corr 1 modify = Injector PW.
Then i just have applicable values in the idle range of the custom table so that as the airspeed into the engine increases the calculation authority returns to the VE Table.
Its working perfectly.
Also in my testing, even when my IAT is in the 60’s and the custom correction to the Inj PW is around 15% the Target fuel from table (Lambda Target Table 1) is not affected.
I’m sure you’ll find it to be a great solution.
I have the same issue with my car. If I start it and let it warm up just idling, it will reach the lambda target no problem, if the car is at 90°C CLT, the lambda target is still good. If I let it idle for a couple more minutes, the car get’s leaner and leaner up to a point where my 58% VE has to be increased to 63% to combat this. At 23°C IAT it’s good, at 35°C it’s lean (lambda 1.05, target is 0.95)
I’ll try the custom correction, however my IAT doesn’t go to 60°C before troubles start happening.
