I'm using LU47's and Roush's data. Stock Ford MAF period table and it is spot on when I check period in the scanner with period >airflow in the tune table IE 446.0 = .92 Lbs of air in the tune and the scanner reports .92 Lbs of air. So I believe the MAF curve is spot on.
Now for the problem. At low engine speeds the car is running 10% rich, the ECU is pulling 10% fuel.
How do I adjust the injector info to make this closer to 2%?
Last edited by K44; 11-06-2021 at 12:34 PM.
Just as you would adjust the air flow rate per fuel trim percentage when tuning MAF transfer, you would adjust fuel flow rate to minimize fuel trim corrections.
airflow and fuel flow.jpg
OK, so I should subtract 10% from the low flow rate? Flash then fine tune?
Higher flow rates will shorten injector pulse width (less fuel)
Lower flow rates will increase injector pulse width (more fuel)
Thanks
what your saying makes no sense
the ecu doesn't know actual airmass it reads it from the maf. Your always going to read the airmass from the maf transfer when logging. If the ecu knew the actual airmass then it wouldn't need a maf sensor.
In any case you need to see if its a global 10% correction. if so, just reduce the high slope and low slope by 10% to add in that 10% fuel.
decipha @ EFIDynoTuning
http://www.efidynotuning.com/
OK, so you are saying whatever I load in the tune as the MAF curve is what the scanner will report? Makes sense.
So there is no real way to verify proper MAF sensor reporting?
It was not global I ended up removing 8% from the low slope and 1% from the high.
I'm using Ford MAF curve for the stock MAF tube for a 17 so can I safely assume it is correct?
decipha,
looking over your web site.
My 18 plus MY year MAF data matches your posted values. I can't find any 15 to 17 MY data. When I load 18 plus MY data with a 18 up MAF tube my fuel trims are off.
Looking at your LU47 injector data it does not jibe with Roush or Ford or what I ended up with.
Do I have something wrong with my car?
I really need some help here.
Last edited by K44; 11-09-2021 at 12:11 AM.
MAF transfer can compensate injector data that is slightly off, heck it can compensate a lot but that is not a correct way to do that.
Long time ago I decided to no care much about 10% trims, I just go and correct that "imperfection" which sometimes makes no sense or rhyme.
This is how one go and tune unknown injectors with no data whatsoever...
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Thats why the fuel trims are there right? To make up for what the calibration can't predict. Either way 0% trims 10% trims, the final air fuel ratio being targeted is achieved.Originally Posted by veeefour
My problem was when using the MAF to correct I could not hold an RPM out of gear.
I really hate throttle by wire
Correct.
The "book" will tell you to always have a proper injector data - should you believe your data is correct(DW data for example is extremely guesstimated, they base on Bosh injectors).
MAF transfer on the other hand is a very efficient and fast way to fix literally everything. You can always say its wrong should you want to...even tho its not.
MAP on the other hand not so much...even tho MAP is basically "known manifold volume per pulse" estimated at atmospheric pressure, here things can go way south if you tell the model: hey you are wrong. Better to "massage" injector slopes in this category given HPT SD calc is far from being perfect.
Last edited by veeefour; 11-10-2021 at 02:55 AM.
v-performance.pl/
facebook.com/veee.performance/
https://www.instagram.com/v.performance.pl/
Remote tuning:
[email protected]
+48 697276579
You have to be a little bit careful when adjusting injector data. Adjusting offset, low slope, or breakpoint can have major fueling changes at low pulse widths. As well, these values are all interconnected, so to keep things from acting very poorly, they all have to functionally flow from one to the next as best to represent what the injector is actually doing.
Ford Graph.png
Here is a visual representation ( NOT an LU47 ) The x-intercept of the low slope would be your offset, changing this value simply applies a phase shift to your lines. The upper point of the low slope is the break point, which is shared as the starting point for the high slope.
Last edited by nicks1031; 11-10-2021 at 08:33 AM.
One reason I am scratching my head on the LU47's is Roush has at least 2 diffrent set ups, Ford has different settings than either Roush. I ended up with values that are not the same as any I can find and decipha has some data on his site that don't match anything I can find.
So what gives? My fuel pressure is 58 psi on a calibrated gauge. I would think that all specs, flow rates, would match for this or any PSI.
((Mass airflow)/(engine speed))/(half the number of cylinders) = (airmass) OR (airload)*(engine displacement) as HPT calls it, its really standard air charge as Steven states in his SD sticky.
(airmass)/((commanded lambda)*(stoich))=(fuel mass)
^^^ this is how you get the fuel mass, its a very small number so give it 5-6 decimal places.
VVV this is the math formulas it goes into to get the pulse width.
((fuel mass)< (breakpoint* pressure multiplier)) - ((Voltage lookup offset*pressure multiplier *offset fuel temp multiplier)*(low slope flowrate* pressure multiplier* slope fuel temp multiplier)))/(low slope flowrate* pressure multiplier* slope fuel temp multiplier)= (pulse time)
OR
((fuel mass)> (breakpoint * pressure multiplier)) - (break point*pressure multiplier))/(high flowrate*pressure multiplier * slope fuel temp multiplier)= (pulse time)
Its actually inverted from what that graph shows when you graph these, and I believe the unit cc/min should actually be fuel mass.
You can set all the multipliers the same to eliminate their input. Making it static and easier, but less flexible. Meaning don't shoot for perfect.
The offset needs to be set first. unlike the breakpoint that is a fuel mass, This is a time determined by the system voltage and acts as minimum pulse width. Some say set it to 0, but as stated above that effects all the pulse widths the low slope can produce, so even if you don't know exactly what it is, set it to some low time or don't change it, because it definitely isn't 0. We aren't shooting for perfect, but not just BSing either.
Then find the low slope that fits low pulse widths the best. You seemed to have figured this out from my first post.
Set a break point and dial in the high slopes. Start high with the break point and it should show you where the low slope starts to go of track once the PW gets big enough. Dial the high slow in just like you did the low slope.
The way you verify this is with what the O2 sensors are saying, is the air to fuel ratio right or wrong. The way you verify the MAF, is with the standard air charge sanity check. is the air load you are seeing for the given manifold air pressure and temperature even possible or not way too low. Example: im seeing 2.0 airload with only 10 psi of boost and 130F* aircharge.... Thats not possible it would take a minimum of 14.7 pounds of boost at 60F* aircharge, you can use lower MAF values and keep you ratio right with modified injector data. Mind you, this effects every table that uses airload, so watch out for what spark and torque does with these sort of changes.
Last edited by murfie; 11-11-2021 at 03:08 AM.
The data I have is the published data probably from muscle motors which does the injector testing for ford. Note that the fuel pressure isn't 58 which you have and the deltap modifiers are already factored in.
If you have a stock inlet, maf and housing then run the stock maf curve and dial in the injectors manually.
decipha @ EFIDynoTuning
http://www.efidynotuning.com/
"If you have a stock inlet, maf and housing then run the stock maf curve and dial in the injectors manually."
That's what I'm doing. Thank you.
I'm learning a lot from your website and from Murfie's posts here. I wish you would update with more coyote stuff.
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