Minimum IPW Info AND Resolution patch
Evolved Member
Joined: Jun 2009
Posts: 653
Likes: 12
From: Houston, TX
I will confirm that this works as intended for the USDM MR.
With FIC 2150's on E85, I observed the following in closed loop idle with average stable idle speed of 850-900.
Below 1.200, the idles runs lean. I am going to speculate that this is as is posted, the injectors get sort of unstable down there. Example.
With mpw set to 1.16x, the car would stablilize at the limit momentarily, resulting in afr of around 17-18. Then would correct by minimum amount, and afr would change to 12-13ish. Going from no a/c on idle to a/c on idle would destabilize the idle, and the car would not really recover because of the compressors cycling. In creep mode, basically idling around, the car would barely run, then randomly speed up when it suddenly added fuel. This was less pronounced with the A/C off.
Setting the minimum value up to 1.192 would mimic the same thing, but when parked on the minimum it would idle a bit richer, at 17-16, and more stable. However when it would make its same correction, up to 1.20x afr would go to 12-13 again. So 1.192 = 16-17, while 1.20x = 12-13.
I settled on 1.200, wich keeps the idle mimimum lean around 15-16. So below 1.200, the FIC 2150 can't increment that small, probably due to physical limitations.
By idling the car in open loop after setting mpw to 1.200, the fuel corrections under very low load driving conditions become much more accurate, preventing fuel trims from skewing negative as the ecu bumps up against the mpw limiter. The result is that while the afr is still a bit all over the place while at very low speed/load driving, they are more stable everywhere else, as the ECU no longer has to redetermine LTFT after doing stop and go traffic, or slow speed driving.
This whole process made me wonder why Mitsu didn't code the ECU to stop trying to subtract more once its on the mpw limit. Maybe that's complicated. I'm not a programmer.
Thanks Tephra for getting this together. My car now spends more time idling between 14 and 15 than not (was 10-12 before), and afr's everywhere else are now more stable.
With FIC 2150's on E85, I observed the following in closed loop idle with average stable idle speed of 850-900.
Below 1.200, the idles runs lean. I am going to speculate that this is as is posted, the injectors get sort of unstable down there. Example.
With mpw set to 1.16x, the car would stablilize at the limit momentarily, resulting in afr of around 17-18. Then would correct by minimum amount, and afr would change to 12-13ish. Going from no a/c on idle to a/c on idle would destabilize the idle, and the car would not really recover because of the compressors cycling. In creep mode, basically idling around, the car would barely run, then randomly speed up when it suddenly added fuel. This was less pronounced with the A/C off.
Setting the minimum value up to 1.192 would mimic the same thing, but when parked on the minimum it would idle a bit richer, at 17-16, and more stable. However when it would make its same correction, up to 1.20x afr would go to 12-13 again. So 1.192 = 16-17, while 1.20x = 12-13.
I settled on 1.200, wich keeps the idle mimimum lean around 15-16. So below 1.200, the FIC 2150 can't increment that small, probably due to physical limitations.
By idling the car in open loop after setting mpw to 1.200, the fuel corrections under very low load driving conditions become much more accurate, preventing fuel trims from skewing negative as the ecu bumps up against the mpw limiter. The result is that while the afr is still a bit all over the place while at very low speed/load driving, they are more stable everywhere else, as the ECU no longer has to redetermine LTFT after doing stop and go traffic, or slow speed driving.
This whole process made me wonder why Mitsu didn't code the ECU to stop trying to subtract more once its on the mpw limit. Maybe that's complicated. I'm not a programmer.
Thanks Tephra for getting this together. My car now spends more time idling between 14 and 15 than not (was 10-12 before), and afr's everywhere else are now more stable.
Thread Starter
Joined: Feb 2007
Posts: 9,486
Likes: 67
From: Melbourne, Australia
cool 
yeah if you watch the STFT whilst idling in closed loop you will see a sawtooth graph.. where the ECU keeps subtracting fuel upto -25% and then it will jump back to 0% and start all over again...
pretty odd
im glad you worked out the minimum STABLE IPW for those injectors
yeah if you watch the STFT whilst idling in closed loop you will see a sawtooth graph.. where the ECU keeps subtracting fuel upto -25% and then it will jump back to 0% and start all over again...
pretty odd
im glad you worked out the minimum STABLE IPW for those injectors
Evolved Member
Joined: Jun 2009
Posts: 653
Likes: 12
From: Houston, TX
MR owners running 1500cc and larger injectors need to hold off on doing this for now. At least until I get done ruling everything else out (failing fuel pumps, fuel line, whatever)
It appears that this may have some effect on tip in, but I am not certain. Until I get a chance to test on a map that does NOT have this enabled, I wont be able to say for sure if it does or does not.
Basically my car's afr's are behaving very differently when I apply accelerator pedal, wether from a dead stop, or from cruise, and it does not appear to matter if it is a lot of pedal or a little bit.
Tephra, the mod on this patch can be simply undone by installing a map that has not had the switches enabled correct?
It appears that this may have some effect on tip in, but I am not certain. Until I get a chance to test on a map that does NOT have this enabled, I wont be able to say for sure if it does or does not.
Basically my car's afr's are behaving very differently when I apply accelerator pedal, wether from a dead stop, or from cruise, and it does not appear to matter if it is a lot of pedal or a little bit.
Tephra, the mod on this patch can be simply undone by installing a map that has not had the switches enabled correct?
Evolved Member
Joined: Jun 2009
Posts: 653
Likes: 12
From: Houston, TX
Before and after Rom will be in your mail in the morning. Probably night time for you.
I did some testing over the weekend. The effect on tip in off idle may be attributable to the car idling at 12.4 most of the time, so it started pretty fat. So the fueling in my fuel tables reflected that. Same with low load cruising anything below 2.5k rpm. Bringing my open loop switch points down helped. As did adding a LOT of fuel to the tables. However the fuel is back, and the car is much happier at idle.
This made me suspicious of my primary fuel pump. I will order a new one this week, but it will take a bit of time to show up. Once I get a new pump in, if the fueling goes pig rich all of a sudden, then we'll know what the issue was. It is kind of wierd how it would pick the exact same time as I do the ipw patch to start reducing its output. After adjusting my fuel tables by quite a bit to get my fueling back to where it was, my injector duty cycles are the same as they were before, around 58%. This seems wierd also.
I also noticed that the fuel line that came with the AMS fuel rail is extremely hard and brittle. So I am supicious of it as well, so it too is going to be replaced.
As soon as I can say for sure the fueling system on the car is perfect, I'll report back.
The short version is even if none of the things I am suspicious of end up being the culprit, I was still able to get the fuel back into the car. So I guess the rule is to double check your fueling after doing this patch.
I did some testing over the weekend. The effect on tip in off idle may be attributable to the car idling at 12.4 most of the time, so it started pretty fat. So the fueling in my fuel tables reflected that. Same with low load cruising anything below 2.5k rpm. Bringing my open loop switch points down helped. As did adding a LOT of fuel to the tables. However the fuel is back, and the car is much happier at idle.
This made me suspicious of my primary fuel pump. I will order a new one this week, but it will take a bit of time to show up. Once I get a new pump in, if the fueling goes pig rich all of a sudden, then we'll know what the issue was. It is kind of wierd how it would pick the exact same time as I do the ipw patch to start reducing its output. After adjusting my fuel tables by quite a bit to get my fueling back to where it was, my injector duty cycles are the same as they were before, around 58%. This seems wierd also.
I also noticed that the fuel line that came with the AMS fuel rail is extremely hard and brittle. So I am supicious of it as well, so it too is going to be replaced.
As soon as I can say for sure the fueling system on the car is perfect, I'll report back.
The short version is even if none of the things I am suspicious of end up being the culprit, I was still able to get the fuel back into the car. So I guess the rule is to double check your fueling after doing this patch.
Evolving Member
Joined: Feb 2009
Posts: 340
Likes: 2
From: Australia
Quick bump.
Does anyone have the 3 sets of addresses for the 53050009 romid handy?
for this bit
cheers
Does anyone have the 3 sets of addresses for the 53050009 romid handy?
for this bit
<table name="Minimum IPW SHLL0 modifier #1 (0x5345 -> 0x5340)" category="Misc" address="2dd8e" type="1D" scaling="Hex16"/>
<table name="Minimum IPW SHLL0 modifier #2 (0x5945 -> 0x5940)" category="Misc" address="2db82" type="1D" scaling="Hex16"/>
<table name="Minimum IPW Code Path modifier #1 (0x7f09 -> 0x7f06)" category="Misc" address="2dd70" type="1D" scaling="Hex16"/>
<table name="Minimum IPW SHLL0 modifier #2 (0x5945 -> 0x5940)" category="Misc" address="2db82" type="1D" scaling="Hex16"/>
<table name="Minimum IPW Code Path modifier #1 (0x7f09 -> 0x7f06)" category="Misc" address="2dd70" type="1D" scaling="Hex16"/>
Evolved Member
Joined: Oct 2010
Posts: 2,447
Likes: 14
From: Australia
Here you go Beeble - this should do the trick for 53050009:
Code:
<table name="Minimum IPW SHLL0 modifier #1 (0x5345 -> 0x5340)" category="Misc" address="2dd72" type="1D" scaling="Hex16"/> <table name="Minimum IPW SHLL0 modifier #2 (0x5945 -> 0x5940)" category="Misc" address="2db66" type="1D" scaling="Hex16"/> <table name="Minimum IPW Code Path modifier #1 (0x7f09 -> 0x7f06)" category="Misc" address="2dd54" type="1D" scaling="Hex16"/>
Rich
Here is 52360018 if anyone needs it
Code:
<table name="Minimum IPW SHLL0 modifier #1 (0x5345 -> 0x5340)" category="Fuel" address="2da5a" type="1D" scaling="Hex16"/> <table name="Minimum IPW SHLL0 modifier #2 (0x5945 -> 0x5940)" category="Fuel" address="2d84e" type="1D" scaling="Hex16"/> <table name="Minimum IPW Code Path modifier #1 (0x7f09 -> 0x7f06)" category="Fuel" address="2da3c" type="1D" scaling="Hex16"/>
