hot starts, lean at idle
#22
Retired Mech Design Engr
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I have it too, but I'm still NA and my AIT is on front side of stock, rubber elbow, just after the filter box, so it sees all radiation from radiator. Of interest is JasonC SSB's newest comments on injector dead time changing with temperature. Me... I'm hoping that my problem goes away when the AIT is located on FMIC cold tank, but it sounds like ScottP is still having an issue.
Last edited by DNMakinson; 02-12-2014 at 10:02 AM. Reason: Had "Jacob", rather than "JasonC"
#27
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It should help, while it's activated. The problem with using it as the sole solution is that the time of the heat soak varies per driving conditions, and will not help stop-and-go heat soak.
Overall, I totally agree with setting the ASE for each cold condition's first 30 or so seconds (to keep from having cold take-off stumble) and letting the WUE take care of the rest of cold conditions. The WUE wizard seems to assume this as well, as it seems to target the curve to the AFR and no extra enrichment.
But, you would have been adding the ASE at high temps, rather than low, and the WUE would already be off.
Is your AIT in front of the radiator?
Overall, I totally agree with setting the ASE for each cold condition's first 30 or so seconds (to keep from having cold take-off stumble) and letting the WUE take care of the rest of cold conditions. The WUE wizard seems to assume this as well, as it seems to target the curve to the AFR and no extra enrichment.
But, you would have been adding the ASE at high temps, rather than low, and the WUE would already be off.
Is your AIT in front of the radiator?
#32
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Is it really 100* in Texas? Your CLT is only 160, but your MAT, at the intercooler is showing 100. When the AFR first starts reading, you are OK, but as the ASE tapers out, then car goes lean. If the AIT sensor is lying (heat soak), then this can make sense, even with the 1.8% correction, depending on the total MAT corr curve.
The other thing I see is that the VE table is going from 42 to 47 as the idle control valve moves to hold the RPM (VE changes with MAP). I wonder if that area could use more tuning, in particular, the lower KPa having the VE raised.
Last would be, in conjunction with above, injector dead time. If smaller than actual, then very small changes in pulse width can cause high error at idle.
The other thing I see is that the VE table is going from 42 to 47 as the idle control valve moves to hold the RPM (VE changes with MAP). I wonder if that area could use more tuning, in particular, the lower KPa having the VE raised.
Last would be, in conjunction with above, injector dead time. If smaller than actual, then very small changes in pulse width can cause high error at idle.
#35
Retired Mech Design Engr
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I wouldn't change MAT for idle, and I wouldn't allow VEAL to adjust VE in the idle area. If the hot restart is an idle issue only:
1) I would manually increase idle area VE cells.
2) Allow EGO to control AFR at idle
3) Tweak idle VE so that, under normal conditions EGO is pulling about 3% at idle, and at hot restarts EGO is adding about 3% at idle.
Do not change MAT so that the entire VE table is wrong under some conditions. Rather MAT correction should be so that the majority of the VE table is correct over changes in AIT (MAT).
1) I would manually increase idle area VE cells.
2) Allow EGO to control AFR at idle
3) Tweak idle VE so that, under normal conditions EGO is pulling about 3% at idle, and at hot restarts EGO is adding about 3% at idle.
Do not change MAT so that the entire VE table is wrong under some conditions. Rather MAT correction should be so that the majority of the VE table is correct over changes in AIT (MAT).
#37
So I made it much more aggressive in the EGO settings. I got it to go to 15.7-16.1 on restarts with no idle surge then with the tap of the throttle drops in to the 14s. Once down the road car stays in the high 13s at idle. I do not have seq injection. Now I need to tune WE cause its very rich warming up but that should be easy. Thanks for the feedback David props to you.
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