PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

should DFCO changes be made or no?

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Old Jul 31, 2005 | 04:08 PM
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Default should DFCO changes be made or no?

ive been searching and reading about some changing the DFCO limits and what not after cams. is there any need to adjust DFCO for normal driving (after teh tune is complete) or no, leave it stock?
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Old Jul 31, 2005 | 04:49 PM
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I don't see any real need to adjust DFCO limits but it couldn't hurt. The only things I think would need changing after a cam is the Map vs Baro table and your misfire table since a cam generally causes higher Map readings and may cause misfires. I changed my Rpm vs Gear table so DFCO engages at lower speeds(personal preference). I also adjusted my Entry blending vs Rpm table because entering DFCO gave quite a jolt and I wanted entry to be smoother(also personal preference). The only problems I have and can't figure out is when I'm in DFCO and go to hit the brakes my rpms drop below my idle speed, and if I don't go into DFCO and my TQ is locked during deceleration my car will surge. Sometimes it will recover to idle speed quickly and stay there, and others the rpms fluctuate up and down until I come to a stop. The slower I go the more this problem is pronounced.
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Old Jul 31, 2005 | 04:53 PM
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ok so the main thing to change is the map vs baro? mine is at 18 now, but isnt that for entry, so raising it wont do anything
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Old Jul 31, 2005 | 04:57 PM
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A cam causes higher map readings and your map readings must be below what the map vs baro table says or you wont go into DFCO.
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Old Jul 31, 2005 | 05:15 PM
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ah i see, so it has to go below there to set dfco, what should i raise them to?
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Old Jul 31, 2005 | 05:31 PM
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i dont understand this, vs barometric stuff? what is that?
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Old Jul 31, 2005 | 08:29 PM
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I don't understand it either. I just experiment and use what works. The map vs baro is just one of the several qualifications that must be met in order to go into DFCO. Right now I have my entry map set to 44 and my exit map at 54. Does it need to be this high? Probably not but sometimes my car doesn't go into DFCO at its usual time so I just keep adjusting this table higher until the problem seems to go away. By the way you don't need to adjust this table if your car is going into DFCO like it should.
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Old Jul 31, 2005 | 08:34 PM
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how would i know this, if i hit the dfco FTC?
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Old Jul 31, 2005 | 08:45 PM
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i think i see now, my map enable was set to 18, so that means unless i went below that dfco wouldnt come on, i get down to about 20-25 so i should set it to 30 kpa, and ext setting about 10 higher to 40? sound about right?
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Old Aug 1, 2005 | 06:29 PM
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I turned my DCFO off.
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Old Aug 1, 2005 | 06:54 PM
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i would but id like to save a little gas
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Old Aug 1, 2005 | 08:01 PM
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i think i see now, my map enable was set to 18, so that means unless i went below that dfco wouldnt come on, i get down to about 20-25 so i should set it to 30 kpa, and ext setting about 10 higher to 40? sound about right?
Sounds good to me.

how would i know this, if i hit the dfco FTC?
I can tell while driving. When I let off the gas and start coasting, about 2-3 seconds after coasting I feel a little forward jolt and my wideband goes to about 19 to 1 air fuel and my injectors read 0.
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Old Aug 1, 2005 | 08:26 PM
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ok thanks, ill check it out
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Old Aug 2, 2005 | 10:13 AM
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what's DFCO ?
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Old Aug 2, 2005 | 10:51 AM
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deceleration fuel cutoff
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