Gen IV Startup Tune Help
Gen IV Startup Tune Help I replaced the LQ4 in my Chevelle with an L96 and I'm trying to get it running well enough to start street tuning. Here are the specs:
2010 L96 with stock heads and rotating assembly
Summit stage 2 turbo cam (running NA right now)
LS3 intake with the L96 flex fuel injectors and throttle body
E67 ecm running an 07 CTS-V operating system
T56
To the best of my limited knowledge, I have the tune properly set up for the mismatch of truck 6.0 parts and LS3 parts. The engine starts surprisingly quickly but it takes a lot of playing with the throttle to get it to stay running. The log is showing the timing advance is staying pretty close to what the table is commanding, so that doesn't seem to be the problem. I reset the LTFTs just before starting the log and you can see them drift to -25% and then stay there. The STFTs start oscillating along with the O2 sensor voltage. I do have a wideband O2 installed but I haven't configured the scanner to log the data yet.
Based on the videos I've watched and the documents I've read, I think the next steps would be:
1. Reduce the sensitivity of the adaptive idle corrections (It's not necessarily idling in the log because I need to keep the throttle pressed, but it seems like the adaptives would be causing the oscillation.)
2. Adjust the virtual VE table based on LTFT data cells
I haven't found as much instruction for Gen IV tuning so I just want to make sure I'm on the right track before making more changes to something I don't fully understand.
2010 L96 with stock heads and rotating assembly
Summit stage 2 turbo cam (running NA right now)
LS3 intake with the L96 flex fuel injectors and throttle body
E67 ecm running an 07 CTS-V operating system
T56
To the best of my limited knowledge, I have the tune properly set up for the mismatch of truck 6.0 parts and LS3 parts. The engine starts surprisingly quickly but it takes a lot of playing with the throttle to get it to stay running. The log is showing the timing advance is staying pretty close to what the table is commanding, so that doesn't seem to be the problem. I reset the LTFTs just before starting the log and you can see them drift to -25% and then stay there. The STFTs start oscillating along with the O2 sensor voltage. I do have a wideband O2 installed but I haven't configured the scanner to log the data yet.
Based on the videos I've watched and the documents I've read, I think the next steps would be:
1. Reduce the sensitivity of the adaptive idle corrections (It's not necessarily idling in the log because I need to keep the throttle pressed, but it seems like the adaptives would be causing the oscillation.)
2. Adjust the virtual VE table based on LTFT data cells
I haven't found as much instruction for Gen IV tuning so I just want to make sure I'm on the right track before making more changes to something I don't fully understand.
I would not by any means call myself a tuner, but yes, your idle to around 1600 will probably need the VE reduced by 20-25%. Then up top around 3600-4000 all the way up, you'll need to add about the same 20-25%.
I would start there, get your wideband reading and setup in the scanner so it populated you afr error. Make sure you have all fuel adders turned off or zeroed out. Once your fuel is a bit closer, then start closing in on the idle.
I would start there, get your wideband reading and setup in the scanner so it populated you afr error. Make sure you have all fuel adders turned off or zeroed out. Once your fuel is a bit closer, then start closing in on the idle.
Just start by dropping that whole low frequency MAF table by 25%. Big change, but you won't be able to begin fine tuning with that big of an offset at the beginning. Speed density is only referenced during transitions so MAF will be your starting spot.
Can't make too many more suggestions as there is no start or idle in that file. But word of advice, try not to get ahead of yourself with changes that you anticipate it will need. It can end up being what feels like a step forward but is actually like 10 steps back when you look at how long it takes to figure out you made a mistake in edit #1. Just follow the issues one by one.
Can't make too many more suggestions as there is no start or idle in that file. But word of advice, try not to get ahead of yourself with changes that you anticipate it will need. It can end up being what feels like a step forward but is actually like 10 steps back when you look at how long it takes to figure out you made a mistake in edit #1. Just follow the issues one by one.
Just start by dropping that whole low frequency MAF table by 25%. Big change, but you won't be able to begin fine tuning with that big of an offset at the beginning. Speed density is only referenced during transitions so MAF will be your starting spot.
Can't make too many more suggestions as there is no start or idle in that file. But word of advice, try not to get ahead of yourself with changes that you anticipate it will need. It can end up being what feels like a step forward but is actually like 10 steps back when you look at how long it takes to figure out you made a mistake in edit #1. Just follow the issues one by one.
Can't make too many more suggestions as there is no start or idle in that file. But word of advice, try not to get ahead of yourself with changes that you anticipate it will need. It can end up being what feels like a step forward but is actually like 10 steps back when you look at how long it takes to figure out you made a mistake in edit #1. Just follow the issues one by one.
When you mention speed density, that means it won't do any good to go in and adjust the virtural VE table at this point, correct? The problem I've been having is that I can't get the engine to idle without applying some throttle. Just for my own understanding, are you suggesting to drop the low frequency MAF table because the larger cam is less efficient at low RPM?
