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Cammed cars/low map VE problems

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Old May 17, 2007 | 12:51 AM
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Default Cammed cars/low map VE problems

How are you guys tuning cammed cars figuring the low map cells(15-35) up to around the 4000rpm range? I've been doing AutoVE( SD ) to my 231/237 112 LS1 and what I believe to be cam reversion keeps these areas skewed. No matter how many logs and adjustments the maps keep showing rich in these cells. Anywhere from .90 to .94. I know this has to be actually leaning the engine out in these areas after too many adjustments so I was looking for a probable fix/cure/remedy. I am using a WB for this and mods are in sig.


Thanks in advance
Shawn
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Old May 17, 2007 | 09:52 AM
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Might be your injectors. If they don't open/close as fast as the stockers, you may have to adjust your injector offset. There was another post in this forum last last couple of days hitting on this topic.
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Old May 17, 2007 | 10:20 AM
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I think your heads are more of a factor in the grand scheme of things. A Road Runner would really help you "see" the averaging that is going on in the pcm. Small, inadvertant changes in adjacent cells to the actual active cells have rash, strange, effects on fueling. RTACS does a pretty awesome job clearing this up.
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Old May 17, 2007 | 11:09 AM
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Use efilive OS5 with TPS fueling near idle and lean it till its stable but still drives nice. TPS fueling will make things smoother as MAP stability is no longer relevant.
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Old May 17, 2007 | 08:20 PM
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Willing to try anything. I'm at a loss. Maybe a walk through adjusting SSpdDmon?
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Old May 17, 2007 | 10:20 PM
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I was asking for the same information...haven't seen it come through yet.

Here's the thread if you want to keep an eye on it:

https://ls1tech.com/forums/pcm-diagnostics-tuning/711580-high-ltfts-cobra-blue-tops.html
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Old May 17, 2007 | 10:54 PM
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Thanks Spd. Looks like I'll be playing with some offsets one step and log at a time. If I figure anything I'll post up.
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Old May 18, 2007 | 08:42 AM
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if its reversion borking the o2 sensors, you try what others have suggested, also adding timing helps, and worse case, you can trick the PCM into going into OL for those cells, and manually set the VE tables to where it runs best.
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Old May 18, 2007 | 02:17 PM
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Been tuning open loop speed density. Timing hasn't helped either.
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Old May 18, 2007 | 02:53 PM
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Where is the WB installed? How rich is it tellting you that you are? 6-10%? Starting at what RPM are you seeing the rich condition? When scanning, are you filtering the histogram for cell counts? You really need atleast a 50 count in each cell to really see a good average of what it is doing. Also, remember that it is really unlikely that the car will spend much time in the 15-35 MAP area. specially at speeds above 2400 RPM. Is DFCO shut off? Are you watching the readings to make sure that you aren't decelerating while populating these cells?
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Old May 18, 2007 | 08:08 PM
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I think you hit it right there. Alot of it is being hit decelerating with DFCO off. I have filtered for TPS and ECT as per AutoVE tutorial but still have a rich condition. The BENS are .90-.96 consistly. 800rpm row = 50-55 MAP. 60 MAP is .99-1.01 which is the idle cell.

1200rpm = 35-50 MAP
1600rpm = 30-45 MAP
2000rpm = 25-45 MAP
2400rpm = 20-25 MAP

These are the areas that are always rich. Ends up leaving a dip in the VE Table and the car starts driving bad.
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