OLSD - Hptuners guys, iat fueling fix?
#84
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microsquirt does not sound better in any way shape or form.....that system is junk
the problem doesnt go away just because you change ECU's...
its a problem that takes tuning to fix...
and most people do not understand how to properly tune, they think you just change the MAF/VE and spark tables and call it a day...that is not how it works
#86
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thats because tuning,as I just stated, is not simple .....
as I would say to any person.....
you cant be lazy and tune....
you have to be willing to look up information and learn new things.
if you are too lazy to learn how to tune... then you shouldnt be tuning in the first place
#87
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Tuning sucks if you're stupid like me. So lets say you got the bias and your tune is finally good. Do you still use STFTs or LTFTs? Do you stay in OL or do you still go into CL at a certain ECT? I only ask because when I had STFTs on my AFR would swing -/+ 0.5 but with it off it would stay within -/+ .1 from stoich while cruising at a constant speed.
Last edited by danieloneil01; 02-10-2014 at 04:43 PM.
#88
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you want to use the Fuel trims for daily corrections...it will still swing a little bit day to day..
air density changes daily.
the point of the narrowband is to swing from rich to lean around stoic....
how much it overshoots in a given time determines fuel trims.
these values can also be adjusted...
stock they are quite far...and they need to be narrowed to a smaller window and update time to be more accurate in a small slice of time
Closed loop is designed to come on after a certain temperature...
I like to see closed loop come on quite early.....using STFT only at colder ECT values...
then when you get to about 20*-30* from yoru normal full operating temps, turn on LTFT as it will be pretty much stable at that point.
air density changes daily.
the point of the narrowband is to swing from rich to lean around stoic....
how much it overshoots in a given time determines fuel trims.
these values can also be adjusted...
stock they are quite far...and they need to be narrowed to a smaller window and update time to be more accurate in a small slice of time
Closed loop is designed to come on after a certain temperature...
I like to see closed loop come on quite early.....using STFT only at colder ECT values...
then when you get to about 20*-30* from yoru normal full operating temps, turn on LTFT as it will be pretty much stable at that point.
#90
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only problems you have are that a narrow band does you no good at anything other than at stoic
so you cant use them for WOT....
so you will still want a wideband with a gauge in the car so you can monitor your air fuel at WOT...
but the narrowbands will take care of part throttle fueling as they were designed to from the factory.
#91
i have tuned a bunch of open loop cars on megasquirt and never had the IAT sensor throwing my Air fuel off so much is the only reason i am interested in what i can do to fix it with no closed loop at all
#92
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That would be correct, if the MAT was actually seeing the 90* temps that are being reported then the air would be less dense which would agree with the less fuel being injected.
As you can see by the description below it is important to not allow the IAT to get false heat soak as it adds another variable to the equation that cannot be adjusted for. IAT is inlet air temp, not inlet air temp with some heat soak. The Bias in itself is setup to account for heat soak of the incoming air. So if you allow the IAT to heat soak you are basically baking in double heat soak into the calculation.
Here is the description on Temp Bias:
As you can see by the description below it is important to not allow the IAT to get false heat soak as it adds another variable to the equation that cannot be adjusted for. IAT is inlet air temp, not inlet air temp with some heat soak. The Bias in itself is setup to account for heat soak of the incoming air. So if you allow the IAT to heat soak you are basically baking in double heat soak into the calculation.
Here is the description on Temp Bias:
#93
spark cut, boost cut, anti lag, all built into microsquirt and not in the stock ECU.
its a great system for starting and racing with a glide or manually shifted auto.
I love a th400 micro car haha
#94
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If I plug that equation from the EFIlive description into an excel sheet to find MAT (which I assume the engine is using in its speed density calculation) and use my known bias factor from my tune, as well as my known ECT and IAT at any given point from my scan log, then the ECT will always bring the MAT value up with a bias >0. If that's the case, why would I ever want any bias towards the ECT at all? It will always make for a higher MAT calculation which will cause the PCM to lean the mixture out.
apparently you have not read anything in this thread...
you need the ECT bias because the fuel itself contributes to the total temperature...fule picks up heat as it travels down the fuel lines/fuel rails and into the cylinders(it even sits on the back of the valve for a bit before getting sucked into the cylinders)
andyou also need the ECT bias because the sensors get heat soaked and read hotter when there is no air movement around them
#95
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apparently you have not read anything in this thread...
you need the ECT bias because the fuel itself contributes to the total temperature...fule picks up heat as it travels down the fuel lines/fuel rails and into the cylinders(it even sits on the back of the valve for a bit before getting sucked into the cylinders)
andyou also need the ECT bias because the sensors get heat soaked and read hotter when there is no air movement around them
you need the ECT bias because the fuel itself contributes to the total temperature...fule picks up heat as it travels down the fuel lines/fuel rails and into the cylinders(it even sits on the back of the valve for a bit before getting sucked into the cylinders)
andyou also need the ECT bias because the sensors get heat soaked and read hotter when there is no air movement around them
#96
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its very simple... it goes back to how VE is calculated..using the Ideal gas law
PV=nRT (where P is the absolute pressure of the gas, V is the volume of the gas, n is the amount of substance of gas (measured in moles), T is the absolute temperature of the gas and R is the ideal, or universal, gas constant.)
100% VE is what this formula represents
(this is also why you cant have over 100% VE on a Naturally aspirated engine..and if you do, your tune is not correct somewhere....but that is another thread all together that I dont feel like talking about right now)
based on the Ideal Gas law which incorporates temperature...
assuming you have an LS1 pcm with a 0 to 2 scale for bias
0 = 100% IAT
2 = 100% ECT
1 = 50% IAT / 50% ECT
Lets say bias is at .75
if IAT is 70*
and ECT is 210*
its going to give you a value that is a blend of those 2.
The formula that GM Uses in the PCM is
273.15+IAT+((ECT-IAT)*factor)
all temperatures are in Kelvin. (because Engineer use Kelvin because all their formulas are in Kelvin and there's no conversion losses between units of measurement)
273.15 + 294.261 + ((372.039 - 294.261)*.75) = 596.57775 Kelvin (614* F at the point of Combustion start)
this is basically compensating for the "Heat soak" you get from the hot fuel temperatures
and again.. the air itself is moving too fast to actually gain much heat from heat soak... 1*~2* at the most at idle...if **** is really hot inside your engine bay
so any heat soak you see is the sensor itself being heated, or the fuel being heated
and any rise in IAT at idle, is either the sensor heat soaking, or actual hot air being drawn in from the engine bay
once your engine is up to full operating temperature...you can determine how much your fuel heat soak and sensor heat soak contributes to the real heat in your Air/Fuel Mixture for the VE formula, and adjust Bias accordingly
also... people who move the sensor outside the engine bay, and get away from the sensor itself heat soaking...typically see very minimal swings in AFR due to fueling calculations and Bias...
its definitely not far off once you get moving..
Last edited by soundengineer; 02-11-2014 at 12:34 AM.
#97
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Dangit, that's a minus sign in that picture. I had it mistaken for a plus sign. I take it back, the equation seems to be sound. Sorry to make you type out that explanation.
Regardless, I still get a lean condition at anything less than the operating temps where my VE table was tuned at. And yes, I've retuned the VE for all the bias values I've tried. The bias table can't account for operating temps using dynamic airflow, so what would you do? For now, I've just manipulated the OLFA table to be abormally rich until it gets up to operating temp. I'm not happy with that method, but it works decently.
Regardless, I still get a lean condition at anything less than the operating temps where my VE table was tuned at. And yes, I've retuned the VE for all the bias values I've tried. The bias table can't account for operating temps using dynamic airflow, so what would you do? For now, I've just manipulated the OLFA table to be abormally rich until it gets up to operating temp. I'm not happy with that method, but it works decently.
Last edited by LTstewy8; 02-11-2014 at 12:50 AM.
#98
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Dangit, that's a minus sign in that picture. I had it mistaken for a plus sign. I take it back, the equation seems to be sound. Sorry to make you type out that explanation.
Regardless, I still get a lean condition at anything less than the operating temps where my VE table was tuned at. And yes, I've retuned the VE for all the bias values I've tried. The bias table can't account for operating temps using dynamic airflow, so what would you do? For now, I've just manipulated the OLFA table to be abormally rich until it gets up to operating temp. I'm not happy with that method, but it works decently.
Regardless, I still get a lean condition at anything less than the operating temps where my VE table was tuned at. And yes, I've retuned the VE for all the bias values I've tried. The bias table can't account for operating temps using dynamic airflow, so what would you do? For now, I've just manipulated the OLFA table to be abormally rich until it gets up to operating temp. I'm not happy with that method, but it works decently.
OLFA is the correct table to do Cold engine temperature Fueling..
#99
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you're right thats why i started with megasquirt cars and just did burnouts and ran 10s fairly easily,
spark cut, boost cut, anti lag, all built into microsquirt and not in the stock ECU.
its a great system for starting and racing with a glide or manually shifted auto.
I love a th400 micro car haha
spark cut, boost cut, anti lag, all built into microsquirt and not in the stock ECU.
its a great system for starting and racing with a glide or manually shifted auto.
I love a th400 micro car haha
Anyhow sorry
#100
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Haha I guess I learned that one the hard way. I did a quick reread at this thread and the others I've been referencing for info on the bias table and I don't think I saw that piece of info anywhere. It's obvious just looking at the variables- I was just expecting a miracle, I suppose. Thanks for clarifying that and putting my worries at ease, I appreciate it.
Last edited by LTstewy8; 02-11-2014 at 11:40 AM.