I was working on my Dad's ls1A this weekend. It's a ls1A PCM on the 385 horse Z06 engine with a cam and drive by cable. T56 car. All swapped in a 1961 Impala. Geoff at EPS provided the initial base line years ago and I was finally going in to fine tune things.
I set the MAF to fail so that I could calc.ve it. I ensured it stayed open loop and my WB02 was in the left bank with the NB02 normally goes. NB02 for left bank was unplugged, and right bank was left in tacted, plugged in.
This lead to a couple challenges-
- The car seemed to always want to idle off the backup VE table. Maybe it runs all the time off the backup, but for sure the idle. Is this normal? Is this because I failed the MAF? Maybe because we unplugged the 02? It makes for a very spiky VE for idle cells as the resolution of the backup is so terrible. Can anyone provide some insight? Is there a PID for backup mode enabled? I always ensured to copy the main VE with labels and paste with labels into the backup table during changes. If I tried to smooth the VE at all after a modification from the log file, the AFR would be way off from desired. This seems to be from poor map resolution and interpolation and such.
- The VE lookup PID does not work for LS1A. What is the proper way to tune the MAF? I tried to improvise and got sane values so I used them. I logged the cylair_dma pid. I made a custom calc to do {calc.w02ben}*{cylair_dma}*{sae.rpm}/15. I charted this against MAF hz. It gave me numbers about 1 gram/s lower on the mid to lower end of the scale and about 30g/s lower on the high end from stock. This is to be expected as the engine has a tiny airfilter mounted right on the MAF, which is mounted right on the throttle body. Anyways, are there any other good ways to perform this task of re-scaling the MAF?
I appreciate any help. Swapping PCM is out of the question, I need to make what he has work- and it does right now for the most part. I just want to understand more about what's going on and ensure everything is 100%.
Thanks!