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Tables with no effect??
Posted:
Wed Sep 06, 2006 8:22 amby m3n0ch3
Hi guys,
I just noticed someting a little weird... it seems the Load vs RPM lambda bias table is either not taken under consideration from the ecu or doesn't work the way it' s intended.
I'm trying to accomplish a nice economy mode while still having lots of power by biasing the AFR in some load/RPM mode to get economy on the highway.... but what ever I put for bias above zero doesn't seem to be modifying AFR.. only number below zero seem to affect it.
Anyone else noticed this?
Posted:
Fri Sep 08, 2006 1:51 amby swifty
I haven't changed that table, but I have changed the closed loop cruise afr and this does make a difference to the afr on cruise.
If you change this though be careful because I believe it has an impact on afr corrections and fuel learning that has a knock on effect in open loop. ie if you lean this out a bit then open loop fuelling may also be leaned out.
Posted:
Fri Sep 08, 2006 9:17 amby m3n0ch3
hmmmm unless I am wrong, in open loop, the ecu is not trying to reach cruise AFR but runs richer...
I set it to 15.3 and my open loop runs are still showing a nice lambda of 0.76 untill 6800 which is my boost decresing limit for now
Posted:
Fri Sep 08, 2006 10:11 pmby xswrex
swifty wrote:I haven't changed that table, but I have changed the closed loop cruise afr and this does make a difference to the afr on cruise.
If you change this though be careful because I believe it has an impact on afr corrections and fuel learning that has a knock on effect in open loop. ie if you lean this out a bit then open loop fuelling may also be leaned out.
The bias tables are referenced in the disassembly, i haven't tracked it down yet to see when they are used.
The closed loop cruise AFR works fine. I have verified it in my ROM (A4SE900D). The resulting RAM value is a word @ 209DE
Posted:
Mon Sep 11, 2006 3:03 amby swifty
Did you set the Cruise aFR to 15.3 before or after setting the open loop afrs ?
Posted:
Thu Sep 14, 2006 6:08 amby ride5000
i set my closed loop afrs before i attacked the open loop table.
however, since a different closed loop afr does not change the fuel trims i do not see how it should have an effect on the open loop afrs.
fwiw my target closed loop is 15.5:1, and my target higest load afr is 11:1