tuning frs maf/injector

[QTR FMS]

Originally Posted by steve99

If everything stock and your getting 14.7 at full throttle on stock tune you got a hardware issue

make sure you just flash stock ecutek rom ie a completly stock factory tune , no racerom feature file added

ie exhaust leak, bad sensor, bad fuel pump bad injectors something hardware.

this is backed up by you saying your deliceous tune hit 13.6 at wot , thats way lean even on E85 and as you say its getting leaner than a couple of months ago.

Stock tune should hit high 10 afr at wot
Id imagine any tune from reputable tuner for petrol should be targeting low 12 at full throttle on petrol

my guess but i changed the fuel pump with a used one from ebay, still same i checked fuel pressure it doesnt get lower than 54psi, i tried changing ratio to di its better than pi but still lean, on open loop it shouldnt use o2 and i have external wideband the reading kinda match sometimes my wideband would read 13.6 and ecu reads 14 but close enough, i dont think i have exhaust leak i would have noticed after a year and a half from adding bolts on,
on stock tune my load doesnt get high enough to reach low afr targets

my load is .7 sometimes .8 on stock tune so i dont think i could get 10 with this load

[steve99]

Originally Posted by QTR FMS

he is saying headers improve airflow that the engine runs leaner so it need higher maf scale

Hmmm
the maf sensor is calibrated to measure air flow. if more air flows the voltage output from maf sensor increases, this is interpreted by ecu as more air flow in gramms/sec and signals ecu to calculate correct fueling.

I dont think ive seen anyone max out the stock maf sensor NA yet. Turbo or SC yes but not NA.

the only time you need to calibrate maf is if you change intake and alter the diameter of the maf tube, this then lowers air velocity past maf sensor (assuming you go bigger diameter) and upsets the calibration.

yes sometimes you can tweak the maf scale slightly to correct ltft but these tweaks should only be few percent.

if your intake is stock and you have had to alter maf scaling more than say 5% you likely have problem .

could be maf sensor , fuel pump injectors, but something is wrong

have you moved the DI computer under bonnett, if so check its bolted up tight via all mount bolts, bad earths on that box will cause you weird fueling issues

[QTR FMS]

Originally Posted by steve99

Hmmm
the maf sensor is calibrated to measure air flow. if more air flows the voltage output from maf sensor increases, this is interpreted by ecu as more air flow in gramms/sec and signals ecu to calculate correct fueling.

I dont think ive seen anyone max out the stock maf sensor NA yet. Turbo or SC yes but not NA.

the only time you need to calibrate maf is if you change intake and alter the diameter of the maf tube, this then lowers air velocity past maf sensor (assuming you go bigger diameter) and upsets the calibration.

yes sometimes you can tweak the maf scale slightly to correct ltft but these tweaks should only be few percent.

i started with oft maf scale today and added 2% over 3.5v and this got me 4%+- but the afr is all over what confuses me is at specific maf voltage there could be a huge afr swing so how do i fix this and the other thing this 2% over 3.5v increase my engine load alot so is there a way to adjust the maf without effecting load

[steve99]

Originally Posted by QTR FMS

i started with oft maf scale today and added 2% over 3.5v and this got me 4%+- but the afr is all over what confuses me is at specific maf voltage there could be a huge afr swing so how do i fix this and the other thing this 2% over 3.5v increase my engine load alot so is there a way to adjust the maf without effecting load

no the maf sensor measures/estimates air flow in to engine in gramms/sec.

this gramms/sec is then used to calcualte the engine "load" relative to rpm.

Subaru Engine Load = MAF (g/sec) * 60 / engine speed (rpm)

so say 150g/sec *60 / 7200 rpm = load load 1.25

note load is a derived parameter and not real engine load, but the ecu uses this derived load for fueling cam timing ignition timing, basicly everything ecu does is based on this load calc

[QTR FMS]

Originally Posted by steve99

no the maf sensor measures/estimates air flow in to engine in gramms/sec.

this gramms/sec is then used to calcualte the engine "load" relative to rpm.

Subaru Engine Load = MAF (g/sec) * 60 / engine speed (rpm)

so say 150g/sec *60 / 7200 rpm = load load 1.25

note load is a derived parameter and not real engine load, but the ecu uses this derived load for fueling cam timing ignition timing, basicly everything ecu does is based on this load calc

yeah i know that so im wondering can i change that 60 to 55 or 50? to get my load corrected

[steve99]

Here is log off car that working correctly

https://datazap.me/u/steve99/uel-v5-...1-2-3-4-7-8-13

at idle you should see maf Volts of about 1.1 v
full throttle at 7000 rpm you should see 4v from maf

this is with stock intake

[steve99]

Originally Posted by QTR FMS

yeah i know that so im wondering can i change that 60 to 55 or 50? to get my load corrected

I think your approaching this wrong.

from your first post your saying that with stock tune stock intake

your idle AFR is 12.7 and full throttle afr is 14

if this is the case you have some hardware problems somewhere

dont try and fix/mask hardware issues by altering tune.

you need to find and fix the underlying problem first

[Kodename47]

I agree with @steve99 that this sounds like a HW issue somewhere.

Why did you change your fuel pump?

Originally Posted by QTR FMS

at specific maf voltage there could be a huge afr swing so how do i fix this

A swing in what way?

Is the AFR relatively stable at idle, it should be closed loop and fluctuate around 14.7. What are the fuel trims when doing so?

[QTR FMS]

Originally Posted by Kodename47

I agree with @steve99 that this sounds like a HW issue somewhere.

Why did you change your fuel pump?


A swing in what way?

Is the AFR relatively stable at idle, it should be closed loop and fluctuate around 14.7. What are the fuel trims when doing so?

i was trying to diagnose the issue,


its because the afr leans out around 5k rpm so i thought i was losing fuel pressure as this is daily/drift car so i have drift the car with almost empty tank so i thought i burned the fuel pump



i burned two fuel pump on my land cruiser when i was driving the car on two wheel with below 1/4 tank so i thought it was the case
it swings depends on rpm and load but even at same maf volts

[QTR FMS]

Originally Posted by steve99

I think your approaching this wrong.

from your first post your saying that with stock tune stock intake

your idle AFR is 12.7 and full throttle afr is 14

if this is the case you have some hardware problems somewhere

dont try and fix/mask hardware issues by altering tune.

you need to find and fix the underlying problem first

at wot its max is around 3.9v
at idle it the voltage is higher than 1v mostly around 1.43v or 1.5v not sure if this number from a cold start or warm but either way i have zeroed the warmup enrichment and lowered my cold idle to 1000rpm and timing to +14 and my maf mode 1 and 2 is the same as 3



so im thinking i might have issue with maf im gonna clean it and see if this makes any difference, i tried to clean it couple of mouths ago but there was no difference, i might replace it later,


im gonna try di only again and check the datalog

[Tor]

Logs would certainly help... 14 AFR sounds very wrong unless it's coming on the throttle (which is still showing a badly adjusted tune). If it's 14 AFR during the pull, I would stop driving the car or at least not go WOT and like Steve suggested start looking for hardware issues.

Edit: Didn't see the thread had grown to 2 pages.

[shr133]

Originally Posted by QTR FMS

jdl uel

k&n drop in filter
1320 over and front pipe
stock mid pipe
nameless muffled track pipe
deleted rear 02 (its disabled in af correction #3)
my flexfuel kit says my tank has e11 with 91
my di has rich wot and pi has lean wot but pi still pig rich idle not sure what is my di idle afr as it switches to pi for idle

Sound like something is off, flex fuel will max out the stock fuel injectors.
Make sure PI are running a min of 25-30% and DI and pump duty is less than 80% ...
When logging make sure you are logging both DI, PI and total fuel quantities to make sure DI is not maxed out....

After logging fuel I had to fix my injection ratio maps.

Below 2000 RPM the stock MAF scaling should be lean.
Make sure your flex fuel maps are set up correctly.

E11 (about .9 volts) no change to 1.30 E85 at 4.7 volts

[Tor]

What makes this difficult is that you are not very specific about where you see which values. Again, a log of a WOT pull is worth more than a thousand words.

When you say:

Originally Posted by QTR FMS

its because the afr leans out around 5k rpms

You mean like this (as a pattern, here the extremes are not really too bad because I start with a MAF scale that I know will roughly fit):

is there a way to adjust the maf without effecting load

No, but you can adjust load without affecting MAF.


Assuming that your problem is just a bumpy AFR curve like above and that you don't actually see 13.8 or 12.9 ALL throughout the pull (if that's the case you have a hardware issue)....

Then the way to do it is:

1) You need a well scaled MAF first. The MAF should not be used to clear the bumps in the WOT AFR curve. It should average them out while the MAF remains a smooth exponential curve.

2) Clear out the bumps in the AFR curve using engine load compensation.

Engine Load Compensation should NOT be used as a means to skip step 1 and make a properly scaled MAF, to begin with.

If the above scenario is your case... Take a few steps back, restore everything regarding the injector back to stock. Use an unmolested MAF scale, like from the OFT tunes. (A bumpy MAF is only harder to make smooth again and, hence, a bad starting point).

Make a full MAF scaling and do not apply any open loop corrections below 3 volts. Make sure that the MAF curve remains smooth and averages out bumps. Do not make bumps in the curve between 2 and 3 volts especially as this will mess up your fuel trims. While doing this try to keep the curve within +/-2% fuel error in CL. Do not make a bump in the transition between <3 volt and >3 volts. In fact, do not make any bump in the curve at all. (Did I say no bumps!).

After that make logs again and this time apply the corrections to the engine load compensation table. Closed loop corrections below 0.8 manifold pressure. And OL corrections above 0.8.

Same car as the screenshot above after MAF scaling and 1 adjustment to ELC (can still be improved a bit):




The problem with all the above is that it takes experience (or a lot of trial and error). The UEL headers of the JDL, Tomei or Gruppe-S design are a bit tricky to tune. They make weird stuff happen to the AFR in the midrange that you need to know how to compensate for.

[QTR FMS]

Originally Posted by shr133

Sound like something is off, flex fuel will max out the stock fuel injectors.
Make sure PI are running a min of 25-30% and DI and pump duty is less than 80% ...
When logging make sure you are logging both DI, PI and total fuel quantities to make sure DI is not maxed out....

After logging fuel I had to fix my injection ratio maps.

Below 2000 RPM the stock MAF scaling should be lean.
Make sure your flex fuel maps are set up correctly.

E11 (about .9 volts) no change to 1.30 E85 at 4.7 volts

im not using flex fuel map yet so my rich issue might be port injector faulty,


my di is at 0.0035s max with 100% di

my pi is at 0.0169s max with 100% pi


on my delicious tuning tune my di is 3.9ms and my pi is 1.24ms max



i dont know how to calculate duty cycle from pulsewidth,


i think i either max out my pi or that i have some issue with it



i tried to upload log but it gives me invalid file