I seem to be having trouble getting a good 128 across the rpm range with my 30 # svo injectors. I can fire up the car and drive to work and the BLM wonders between 124 and 130 cruising down the highway. The change is slow. Should it be rock solid at 128. I keep looking at the plugs and the electrodes are white. I am trying to get ready for the track this weekend and do some spraying on them. Also, my gas mileage just does not seem to get any better. Finally, I am looking at my logs using Excel and sorting them by rpm. I figure if I take the average across a specific rpm I should be alright. Does anyone have a different approach for me to try? I am all ears. Thanks, BranZ

 

If you have your Carbon Canister Purge active it can cause the fuel trim to move a little due to different amounts of fuel vapor coming from the purge system. Does it move around on level sections of the freeway or just on overpasses?

 

124-130, I wouldn't worrry about.

If you're trying to go leaner for mileage, yes, you can get to a point where nothing will seem to matter. Not to mention *stage* of build effects mileage, you just ain't gonna get really good mileage with a more then mild build.
You might try going a tad richer, and taking some timing out. Some combs just don't benefit from much timing in cruise. Try a tune with a max of say 34 in cruise and see what you're mileage is. Running closed loop is going to prevent you from trying other AFRs.

 

I went out last night to work on the tune and decided to run a couple of quarters. I am running ECM582 on the 730 91Z computer. Anyway, I would make a pass and my BLMs were between 135 and 137, which is way too lean for my taste. I reviewed the passes in excel and the whole pass locked into one of the two numbers. I then drove around hitting a cruise speed and everything went back to the normal 124 to 130 ranges. My question is what do I tune to make my wide open passes richer. Does this involve PE or AE? Also, how accurate is the quarter miler in ECM582? Thanks, BranZ