dsp4848
Well-Known Member
- Joined
- Oct 26, 2014
- Threads
- 32
- Messages
- 389
- Reaction score
- 115
- Location
- Hutto, Texas
- First Name
- David
- Vehicle(s)
- 2015 GT PP Magnetic
- Thread starter
- #16
Sorry for the long delay in response. Been trying to move into a house and keep up with work travel as well.Have you flashed your car back to the stock file and tried flashing the Lund file again?
That has fixed some strange fuel trim issues before.
Your STFT and LTFT are fighting each other at idle. But that leaves your actual AFR right where it should be. Just an indication of possible other issues like EVAP stuck.
I think what you are feeling at part throttle is the VCT intake and exhaust being at 0. The intake cam at 0 is actually in the middle as it is a midlock phaser. Its kinda looks like you are meeting the load requirement for OP, but not the pedal so it is not phasing the cams to where they should be. Everything... spark, speed density, torque values, etc. all depend on the cams moving to the right position to get the right mapped point values. Being at 0 when they should be flowing through a few mapped points is not going to give you smooth results.
Instead of messing around in Excel, download SCT livelink Gen II. It will chart all the values for you and you can add histograms to compare two or thee values against each other.
I start with getting a new battery. Put it in. hook a battery charger up. flash the stock file. Then flash the lune file and see how it goes.
Anyway, I did try this a couple of weeks ago - flashing to the stock tune and then to the Lund tune. I did notice that my LTFTs were reset to 0 across all RPMs. Upon startup, no issues whatsoever. Probably the smoothest startup and idle I've had since I was stock. I let the car idle for about 5 minutes and then took it out for a spin. It seemed much smoother on power delivery and after upshifts. I couldn't get the car to exhibit any bucking or surging. That is until the car started learning fuel trim values and mapping the LTFTs. After driving a bit the LTFTs started going deeply negative again (-10% to -25% depending on load/rpm, etc.). At least I have consistency here and the car was able to recreate the same situation from a fresh tune flash with cleared fuel trims.
I have opened up another case with Lund and will attempt to get this sorted out with them. Thanks for the feedback and I will post another update once I know more.
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