Hello everyone, I have just recently got into tuning and tweaking my 09 vette/LS3, E38 Gen 4 engine and I am using VCM Editor 5.04.
I am not a stranger to tuning however anything I have tuned before has been a speed density system.
I have done a pile of reading on this and have done a few things to the car with some success.
I am a little unclear on a few things so I will just post what I have done, how I did it and what I would like to do next.
First off it is a bone stock LS3 and I do not need to tune it extensively, there is just a few things I've tweaked and need to. I'm just looking for some good pointers to help me understand this better and point me in the right direction.
The first thing I did was remapped the electronic throttle. Despite throwing the reduced power code a few times I was able to tweak it and man is the throttle way more responsive. Kind of woke the car up,
Another issue I had was on a cold start it would start and kick up to a fast idle right away, however it would lean misfire for a few seconds before it cleared up. This is something I could live with but since I have HP Tuners and I'm eager to learn I decided to tackle it.
I read that on cold starts its not good to play with the Virtual VE table if its running fine when hot, which it is for the most part and it was recommended to find what frequency the MAF meter was at when it did the stumble, which was basically a lean stumble/misfire.
I found the Hz was at 3400. So I took the value between 2500 and 4000 Hz on the MAF curve and added 20% fuel and resmoothed the map.
I was quite happy after flashing this as it cured my lean stumble.
So, yes I am still learning but I want to make sure I'm going about this the right way and don't want to learn any bad tuning habits.
The last thing I want to fix is when you rev the motor up a bit and hold it at 1700 RPM, it is at 25kpa on the MAP sensor it goes into a lean stumble.
If you press the gas a bit you can push it through and by about 2200 rpm it clears up.
So I'm a bit confused by what I have been reading and not exactly sure how to go about this.
I know that the EQ commanded AFR is 14.7 at this spot on the map.
Being this is an issue when the engine is warmed up and in CL, Is this something I should increase the value in the Virtual VE table? Or is the EQ commanded AFR table accessible and the target AFR needs to be lowered to correct the lean stumble? I know I have to add fuel in somehow, but how?
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Originally Posted by blindsquirrel
