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Idle/Fuel Pressure/VE/DFCO

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Old 02-03-2005, 06:54 AM
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Default Idle/Fuel Pressure/VE/DFCO

I currently have a inline and intank fuel pump installed in my car which changes my Fuel Pressure. At idle it varies from 64-67PSI and the same goes for different throttle positions. My delima is this, I am trying to get my VE table dialed in, but with the varying fuel pressure, it makes this difficult. Is there something that can be done to fix/remedy this problem??

Also, I have disabled my DFCO and Idle Proportional tables in Tuners. It appears that my car still goes lean (16.0-21.0) on decel and for a short period of time when you let off of the gas. On the DFCO, I have changed the TEMP, RPMS, and MAP and it still doesn't seem to work.

Car is being tuned Mafless in constant open loop.
Old 02-03-2005, 09:34 AM
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your inline has to run all the time? you might just have to run a return line and put a 97 corvette fuel rail on with a regulator?? That would keep it at a flat fuel pressure. You have raised the ve table on decell cells and it doesnt change anything??
Old 02-03-2005, 10:38 AM
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Yes he has him and I were seeing the same problems. You should see our ve tables at 4k and 15 kpa. Looks like mount everest compared to the rest of the table and moving the ve does nothing to help it
Old 02-03-2005, 10:51 AM
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hmm, maybe an an airleak somewhere and the super high vacuum is just pulling it in somewhere.
Old 02-03-2005, 10:54 AM
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I'm having the exact same problem as well. The cells in the upper left hand portion of the VE table are lean. No amount of changes to VE helps. In fact, it causes my surging to increase. I've been beating my head against a wall for 2 weeks on this now with nothing to show for it except a bruise.
Old 02-03-2005, 11:07 AM
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I don't think its a air leak Jes my **** is on and made sure it was tight. I have dealt with a air leak before and its not a fun thing. I don't know what the problem is. When I change the ve table to correspond, it does nothing really.
Old 02-03-2005, 11:34 AM
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its easy to get unmetered air into a motor at those kinds of rpms on decell, it could come thru the valve stems, in from the rings of a cylinder from the crank case, an eghaust leak, ect. sorry, i didnt mean anything bad, Are the injector pulse widths and fuel pressure good when this happens? Or is the computer showing the injectors shutting off?
Old 02-03-2005, 11:40 AM
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I'll have to take a look at my logs when I get off of work. I know at idle my IPW is about 3.0. I don't know what to do to correct the fuel pressure problem. Also, I would suspect that not all of us here have a air leak as this seems to be a common occurance.
Old 02-03-2005, 11:43 AM
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maybe it can be adjusted by the injector offset vs voltage vs map table. Or your injector flow rate table on the last cell.
Old 02-03-2005, 11:56 AM
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I was wondering if I could re-adjust my IFR table (not offset) with the new PSI and see if that makes a difference.
Old 02-04-2005, 06:19 AM
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It appears for a split second the IPW goes to 0.4 and then back up to 3.0 when I let off of the gas for a second or two. I dunno what it is.




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