The table only goes to 2000 rpm. My question for that part was, what is the rpm limit for the EGR DC? Its not listed in the XDF.
'86 Grand National
Scratch that. EGR is functioning properly and my questions have been answered. This morning I observed effects of the EGR and found that it provides no increase in fuel milage. Depending on the duty cycle, the impact negatively affected fuel milage. As soon as DC rose above 30% I noticed an increase in BLM counts. Not satisfied with that observation I toggled EGR on and off while highway mode was active, watching NBO2 readings similtaneously. With EGR DC at or above 30%, the A/F mixture would lean out, ~30-50mV. While it helps with emissions, it doesnt help fuel milage at all, at least in my case. Toggled off, the BLM counts fell back down to where im used to observing them, some cells fell by 6 counts. So I have no use for EGR anymore.
'86 Grand National
BLM is only giving you the difference between the airflow the ECM thinks is there (after subtracting out the EGR that it thinks is there) compared with what is actually happening on the engine, not the actual fuel economy. I think that generation of ECM had a BPC vs. EGR calibration in there somewhere and any error in that calibration would show up as a BLM shift. There will be an emissions benefit but you should see a slight mileage improvement when looking at the pulse width at the same vehicle speed - you'd need to log injector pulse width, RPM, vehicle speed and integrate pulse width * RPM and compare against miles (or kilometres) driven to get at least a semi-accurate reading. Also EGR is usually set up to allow more advanced ignition timing - maybe 5 to 8 crank degrees - which should help your efficiency numbers. I don't know if I've ever seen a calibrated EGR system make efficiency drop, but certainly if the timing isn't adjusted up that can happen. That being said, with EGR there is a peak efficiency point where you've lowered NOx as much as you can and advanced the timing as much as you can and if you increase the flow rate any more then you get an efficiency drop - if some is good, more is not necessarily better. Just like tequila. It also should help lower the exhaust temperatures at part-throttle.
1994 6.5L 4L80E K
2001 VW GTI
2006 Smart ForTwo CDI
I know $42 has a scaler for EGR on/off, iirc $88 uses a modifier table, and $24 as well. There isnt any modifier I could find for spark or fuel in the S_AUJP xdf, and im not capable of finding something like that in the disassembly yet. I will make a note of the items to be logged and will record while on my way home from work. Even $24 has more modifiers that could be used. When I get home ill also look thru other $8D masks to see if there is more available items, if so ill put them in the S_AUJP xdf as long as the locations match up.
'86 Grand National
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