I have been trying to tune my car, but am having some very flaky responses when changing parameters. I had KC Maxx in KC help me over the weekend thinking that I may be doing something wrong, but Ryan had similar issues and had never seen anything like this before...so looking for any help/input before buying a new ECM.
Here is what I have for a config....
General setup is Trailblazer LS2 6.0L
E40 - out of a 2006 GMC Envoy 5.3L
LS2 DBW
2006 MAF/MAP/Crank/rear mount cam sensor
2010 camaro downstream o2 sensors
LS3 Intake/Injectors/Heads
XER273HR-14 224/230 dur@50 581/588lift
T-56 trans
Symptoms;
No errors or codes from any of the sensors.
MAF frequency readings align with what Ryan expected.
Started off with a typical GTO LS2 parameter set on the dyno; car would not make any power, fueling was sporadic fluctuating mostly lean and would die when going to neutral on dyno after pull. The car acted like it was in limp or power reduction mode from traction control or something like that.
Made a slight change in MAF and fueling tables, performed calibration update; when starting up you could tell that the system was working right. Made a full pull to 6500. MAF HZ looked good, AFR was linear, and no KR.
Adjusted MAF table 5%, fueling table to lean out some down low and richen up on top end, performed calibration update; system went abnormal again exhibiting same characteristics. (Nothing else was changed)
Tried loading the same settings with full write to ECM, no joy - same behavior. Any slight changed makes the systems unstable.
Reverted back to the previous file we were able to make a full pull on; as soon as car started the system was working properly and was able to make a full pull. Then when we pulled car off dyno to load back on trailer, the car started misbehaving again. Turned car off, started it again, and it cleared up...weird!!!
I have yet to fully confirm grounding issues, but will once I get the full pin-out on the harness.
Could it be the base OS on the ECM causing the issues? If so, could reloading base SW with Tech2 fix it or is it best to get a different ECM?
Many Thanks!