Max ve is at max torque
Max ve is at max torque
Today I reduced the Injector Bias by 20%, and increased the VE table by 20%, turned off PE, unlocked the BLMs from 128, and went for a drive. 20% brought the highest VE to 90.
Had a slight surge at 2000 and 30kPa, but I got some good datalogging in. The INT was doing its thing, the BLM still went lean, but not so dramatically. Engine still ran pretty good. Corrected the VE table using BLMs, then zeroed everything in Decel Enleanment and drove some more. BLMs stopped working (I have since returned the DE settings to factory).
Nevertheless, I still datalogged, but checked the INT History when I got home, and they were all very close to 126-128 themselves.
This afternoon I've been playing with subtle changes to the Spark Table.
I'm hoping that as the VE gets closer, and the INT and BLM is happier, I'll have less issues with surging. It -does- seem to be improving itself as I've datalogged and tweaked the VE table.
Got a PM suggesting the higher fuel pressure might be an issue.
Which got me thinking, and looking back at the logs. It doesn't seem to find stoich at idle at all, which is the same VE value as light cruise at 2000rpm. As the PM'r suggested, it might not be able to run a low enough PW at such low fuel requirements.
Since I changed to an external aftermarket fuel pressure regulator that can be vacuum referenced, I think I'm going to hook it the vacuum and see if that can help me actually run with lower VE values at the bottom of the table.
I seem to recall reading of people having issues tuning with a vacuum referenced fuel pressure regulator, so I need to do some research to see what the issues are.
With vacuum set up, I get 12psi at idle, which should make the injectors happy. It "felt" a whole lot better driving around, but my BLMs weren't moving, so I just did some slight smoothing and tweaking of the table with only one drive today. Lots of family stuff to do this weekend, so I didn't get much driving in at all.
Did three more datalogs and tunes, and it's running a whole lot better. I had less and less surging with each tune, but this was mostly all light throttle.
Note: The BLM Coolant Temp Thresholds are set from the factory at Min: 189° and Max: 0°. Don't change those to numbers that are logical (like I did - Min:0° Max:189°), or the BLMs will stop working.
So far, then, hypothetically: The whole cause of my original question (this thread), may just very well be that 18psi is too much, the injectors lose their stability, and the O2 has a fit trying to correct it. Maybe?
Thoughts?
Feedback?
BLMs are currently 126 to 129s.
why not disable closed loop and just add or subtracting fuel until it runs right, then go back with the wideband and fine tune a bit?
i found that the ECM is so dumb that it'll go into closed loop if you cut the o2 wire off halfway, and wont even run abnormally or complain about it. i remember someone telling me the wire acts like an antenna or something and picks up false cross-counts so it thinks it's running right.
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