erratic LTFT

[meatbag]

Been working on a single turbo 2010 camaro that has been driving me nuts on the LTFT's. I will admit this is my first SD tune on a newer ECU so I might be missing something obvious. The sensors are post turbo in the downpipe but for some reason they tend to trim themselves in opposite directions. After a couple of min you end up with one bank at a positive percentage and the other at some negative percentage. This only happens at idle. Otherwise I can get the trims set and everything cycling around stoich like it is supposed to and the next time I start the car they are 10-20% off.I know this is partly do to having no injector data but ive never had one vary so much.

[MMGT1]

Stock or cammed? Got a feeling vac is messing with the sensor. Adjustable blow off valve on it by chance? If so, tighten it a little until there is just a little air bleeding at the valve at idle. Then check to make sure it is opening when it should on decel and shifts. Very fine line between the two

[MMGT1]

To add, your scan is a dead ringer to what I just had happen 2 days ago with mine! The long swooping O2 readings are why Im thinking this man

[meatbag]

Stock cam car with a tial bov so i can only adjust spring pressure but it is staying shut at idle and opening on decel. The car is auto so it doesnt do much between shifts.

I am running the car pure SD at this point so even if the bov was bleeding off air it shouldnt effect the fueling.

[MMGT1]

Man, that is strange then. Your scan looks EXACTLY like mine did with that spring issue. Dissable the dam cat test on it and see if it has any effect... yea, Im pissin' in the wind here, but might be something to at least try

[IDRIVEAG8GT]

Wow, you know I have this same problem with the Kenne Bell cars/trucks. Total different setup but the design of the intake is what messes with the trims. One bank gets more air, the other, not so much, therefore the trims go whacky. I'm actually pulling the manifold apart right now to see if I can figure out what's going.

On another note, partially collapsed lifter will cause something similar to what you are seeing.

[meatbag]

True but the sensors are in the same pipe so they are reading the same airstream.

On another note does anyone know how spark is calculated? I have the maf disabled but it still seems to base spark off of maf readings. Anyway to get around this because the maf signal is extremely dirty and it is causing the spark to be all over the place.

[Mep_q8]

I know this is partly do to having no injector data but ive never had one vary so much.

Thats exactly the reason why. You'll be chasing an endless route unless you get those injectors dialed in as close as you can, and then compensate for them in the VE tables. Goodluck.

[meatbag]

Got the trims sqaured away by changing injectors and relocating the O2 sensors to a different position.

Now that I am getting more into the WOT tuning I keep getting this timing fluctiation when the car is going through a run. I can not find what is pulling/adding timing.