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Rich during decel pulsewidth issue

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Old Nov 8, 2023 | 09:21 AM
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Default Rich during decel pulsewidth issue

Hey guys. Have a blown ls1 on 2 bar OS, 60# dekas. Adj fpr
im having an issue doing dfco disabled tuning I can’t get around.
during all decel it is going super rich, pulling 20% etc, however when getting on throttle it is pulling so much fuel it stumbles, even after a long coast down coming back to idle it is starving for fuel and stumbles until the stfts come closer to 0.

What’s interesting is the pulsewidths are LOCKED at 2.0 only during decel, any throttle and they accept the stft adjustments and go to 1.5ms etc and that makes me stupid lean until the stft comes back to near 0
does anyone have any idea how to fix this and let the injectors do wtf I have set in my VE table during decel?
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Old Nov 8, 2023 | 09:32 AM
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Assuming it’s a 0411 ecu there is a single field that drives the minimum transient pulse width.
I can’t remember the designator in efilive.
with large injectors it needs to be reduced or it causes what you’re seeing.
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Old Nov 8, 2023 | 09:34 AM
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Old Nov 8, 2023 | 09:35 AM
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Originally Posted by TrendSetter
Assuming it’s a 0411 ecu there is a single field that drives the minimum transient pulse width.
I can’t remember the designator in efilive.
with large injectors it needs to be reduced or it causes what you’re seeing.
sorry I should have mentioned this, my min transient fueling is .010
should I reduce this further?
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Old Nov 8, 2023 | 10:07 AM
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I don’t have my laptop with me but if you post your tune and a log showing your problem you will get a lot more help.
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Old Nov 8, 2023 | 10:51 AM
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What injector data did you use? Where did it come from?

By all means post the tune.

Transient fuel Min fuel milligrams is a somewhat confusing entry. Is it a limit? What happens if you set it to low?
Always seemed like the injector manufacturers should provide the correct number.
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Old Nov 8, 2023 | 12:33 PM
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I MAY HAVE FIXED IT! Woohoo. I took 20% out of the min and def pulse tables. I’m now seeing 1.3ms on decel. Obviously +20% lean now as I butchered my ve going on the bad data. Haha. What’s really odd to me, however, is on my logs as soon as I would open the throttle up it would allow my min ejector pulse to bottom to 1.6ms and thus making me stupid lean under any throttle. For anyone else, I’ll post my min/default values here, this fixed my issue. I’m running 60PSI base on a 1:1. 8AN feed, 6an return dead headed setup


Having to redo my entire low end VE table. Pain the ****. I will post my tune when I get home and you can take a look. I’d like some insight on my spark table anyway as well, I have it in the dirt but now that I have this new cam tuned I’d like to start ramping timing down less aggressively. Car is PRC 225 with 62cc chambers but currently running ls9 gaskets and studs so probably 10.7ish:1 compression. Procharger car running 50/50 meth 12GPH nozzle progressive kit. Custom Martin Smallwood cam, 228/244 .612/.612 113+3LSA
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Old Nov 8, 2023 | 12:48 PM
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I’ve always just nearly zeroed out that stuff but haven’t really seen many others do that so I’m hesitant to recommend it. It’s worked well for me and I haven’t found any adverse side effects.
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Old Nov 8, 2023 | 02:15 PM
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Originally Posted by TrendSetter
I’ve always just nearly zeroed out that stuff but haven’t really seen many others do that so I’m hesitant to recommend it. It’s worked well for me and I haven’t found any adverse side effects.
Im not super sure on it, since it basically locked me rich and caused a severe lean tip in, however it may be worthwhile to tune it in to help transients if you have a big cam running SD like my prior one. It had really shitty VE resolution in low rpm so when i got the MAF out of there it was a nightmare between idling and 20% throttle I only saw a kpa change of 2-5 until i got to 1600ish rpm lol. But other than that, im not sure what it would be for, all it did for me was **** up my VE table and prevent my O2 sensors from doing their job. Oddly enough that was widely posted injector data that has been posted on this forum multiple times, I never could get the decel to lean out on my prior cam but my dfco covered it usually. glad I figured it out, also this is my tune and logs that go with it. First time ive really pushed the car up into higher rpm for stft tuning, glad it was kind of close.
Attached Files
File Type: hpl
tune 17 cruise.hpl (1.94 MB, 42 views)
File Type: hpl
tune 17 wot.hpl (185.7 KB, 38 views)
File Type: hpt
tune 17 v2.hpt (224.3 KB, 35 views)

Last edited by mstansbury0704; Nov 8, 2023 at 02:29 PM.
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