When tuning these gen 1 platform vehicles I notice that when idling or cruising the EQ ratio swings above and below 1.0 lambda which sometimes will create an idle oscillation on cars with larger injectors or forced induction. I have looked and looked for what table would create this issue without success... Anyone care to share some knowledge with me?
Closed loop causes this, disable oxygen sensors and it won't oscillate. It's all emissions and catalytic converter related. Kinda puts you in the dark on actual afr, but your command should get stable.
I don't think the problem you are seeing is caused by what you think is causing it, and don't actually recommend disabling closed loop. Idle is all target RPM and spark control to achieve that target. It just needs enough air to allow spark to be less than MBT and the proper amount of fuel to meet the stoich ratio, it does try or need to oscillate or move this around very much when compared to spark.
I'm not going to disable closed loop. That's not the point. The point is there any way to make the eq commanded just stay at 1.000 instead of swinging 1.021 and 9.812 or whatever
Add 5% to etc idle throttle angle and see if that worksOriginally Posted by konabluekiller
I am having a similar issue. TT 60mm 2012 coyote, lu47#, billet opg and crank gears (done and started , ran great). Then tt kit installed. Was having a bad hunting idle, anywhere from 1000rpm -400rpm swing. Scaled maf by measuring stock intake vs aftermarket. Issue is I have a very unstable afr/lambda. Lamda swings from 0.65 - 1.5 according to factory wideband and aftermarket wb on closed loop. On cold starts car idle at 11.5 afr and gradually leans out, by the time it switches to closed loop afr is all over the place roughly 1 minute later. I have applied stft - ltft corrections to maf vs period with it still pulling fuel around idle range anywhere from -2 - -30 depending on how bad the idle dips. Flange temp, o2 sensor, decel fuel cut off disabled (enable rpm set 7000). WOT lambda table set at 1.00. Cylair anti diasabled. Cot over temp disabled ( think I have covered all necessary sensors to be disabled). No matter how many time I apply the stft - ltft corrections to the maf vs period I still have erratic lambda/afr readings. Any suggestions?
Reply With Quote