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64 Posts
Discussion Starter · #1 ·
96 Mustang Cobra, 4.6 4v, CDAN4 / LLX3 calibration. Using Binary Editor + Quarterhorse.

Scaled tune down because I believe I was clipping injectors at WOT at very top end due to leaning out right at ~4.65v maf even after dumping fuel into the maf curve right at that point. Using 60# injectors I did not realize that the ECU couldn't support that high so I researched and scaled down. Now my current issue is having 3rd gear @2.4v maf being at 15.5AFR but if I shift right into 4th gear and sit at 2.4v maf it's a perfect 14.6 (targeting it). Only don't speak in lambda because gauge outputs AFR. This is also with holding the 2.4v maf point for at least 3 seconds each time. Tested multiple times just to verify and confirm. At op temp as well.

Scaling percentage being: 2.0089

Before injector settings:
Fuel Injector Breakpoint0.00003362
Fuel Injector High Slope60.267
Fuel Injector Low Slope63.187

Fuel Injector Breakpoint0.00001675
Fuel Injector High Slope30.000
Fuel Injector Low Slope31.455

Scaled down the MAF curve lbs/min, engine displacement size, manifold volume, and that's it. Taking from's fuel write-up of scaling these are the last few PIDs I couldn't find which I don't believe apply to me. (Return fuel system, TPREL was for later model mustangs, Min idle airmass clip just could not find)

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91 GT, 302 with twisted wedge heads, XE270HR-12 cam, track heat intake, 80 lb injectors, Vortech SI
13 Posts
I use Tunerpro RT instead of Binary Editor so my situation may be different, but I have to enter new fueling numbers in a particular order. Changing the high slope automatically changes the other injector parameters, SARCHG, and the MAF curve so I have to write down the other parameters and apply that scaling outside of the program, then copy and paste back into the program. Otherwise changing the high slope will instantly scale the other parameters, then when I go to scale the other parameters I would be scaling an already scaled number and my fueling would be off.

Again, I'm not sure if this applies to Binary Editor.

Edit: Your fueling error at 2.4 MAF V at high vs low rpm sounds like either the breakpoint or low slope being off a bit. The high rpm low load condition is likely a short enough injector pulse width to be below or near the breakpoint, so the low slope has much more influence. If fueling seems fine at idle and at other conditions where you're firmly below the breakpoint, and it's fine at high loads well above the breakpoint, but it's lean at the transition from low to high slope you might you might want to lower the breakpoint. Decipha has a writeup on this at the bottom of the fueling section.

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294 Posts
I can confirm the above ordering of changes doesn't apply to BE.

I also agree that it appears you are close after scaling and just need to dial it in. When making tweaks with a scaled tune, be aware that smaller changes make a bigger difference as there is a loss of resolution with scaling.

Also beware there may be some transient fueling functions that also need to be scaled that weren't mentioned in the write up above. I'm not too familiar with the CDAN4 strategy to suggest what these are though.
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