I just finished an LS7 swap in my 69 Camaro and I?m having issues with the car going way lean when tuning using the MAF. The engine has a custom 249/258 cam, ported heads, 11.5:1 compression, FAST intake, and a 102mm TB. I'm using an E38 PCM and a modified engine harness from a 2015 Z28. I was able to tune my previous LS1 with the Gen 3 0411 PCM, but that's the only experience I have.
First of all, I've dialed in virtual volumetric efficiency tables reasonably well below 4000 RPM. The only issue I ran into is the engine wants to pull the throttle above 4,500-5,500 RPM when near/at WOT even though I thought I turned torque management off. It also seems like the cutoff RPM is dependent on what gear I'm in.
Now that I've switched over to MAF tuning, I'm running into two problems that won't allow me to dial in the MAF frequency tables.
1. The engine still wants to limit itself around 5,500RPM when at WOT. I'm guessing it's a simple parameter I missed somewhere.
2. The big problem is that the engine will randomly start running lean. You can see in the posted log, that about half way through the drive it starts "snapping" lean on me for no apparent reason. As the drive goes on, it gets more frequent until it's almost always in the lean condition. There is no obvious cause since RPMs, MAP, MAF, Spark, Fuel Pressure, Injector DC all seem to stay the same when it does it. This isn't a wideband issue because the car will barely run and start popping really bad when it does this. I did find that if I brought the RPMs up and gave it some throttle it would typically go back to a normal AFR momentarily.
Things to Note:
I am running LSA/LS9 injectors that were bought used. I'm almost wondering if they were modified because the VVE table I ended up with is SO far off from the stock table. So possibly incorrect injector data.
I took the plugs out after the drive to see if it was maybe isolated to a single bank or cylinder, but all of the plugs looked similar to each other.
It's odd that the injector duty cycle isn't changing when it goes lean, so I still haven't ruled out a harness issue.
I tried turning off the knock retard to see if that could be the issue ? it wasn't
Probably has nothing to do with it, but the transmission is out of a 2002 Camaro, so the gear ratios are different.