VE tuning with PE off?
08-27-2005, 05:06 PM
#2
TECH Senior Member
if you're using a wideband and have your open loop tables set to a safe AFR (say 13.0:1 or richer) then you can turn PE off
But if you're tuning off the fuel trim table only, I wouldn't turn it off... set it to not turn on till about 50% throttle maybe... but you don't want it off... 14.7:1 AFR at WOT/heavy load/high RPM isn't a good thing
But if you're tuning off the fuel trim table only, I wouldn't turn it off... set it to not turn on till about 50% throttle maybe... but you don't want it off... 14.7:1 AFR at WOT/heavy load/high RPM isn't a good thing
08-27-2005, 05:21 PM
#3
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I dont turn pe off. I keep it still enabled and tune from there. My OLFA table is set to .988 and my pe set to 1.13 havent seen any problems yet. GM does this from the factory on the 03 Silvy and the 05 CTS-v. THose so fare are the later model years i have looked at and seen it done this way
08-28-2005, 05:54 AM
#6
Now you're making me wonder if I should leave my PE enabled when tuning open loop SD with my wideband...right now I'm tuning ~half the table to an OLFA value of 1.0 (up to 2.8k RPMs), and the rest to 1.13. I'd think it'd be a little harder to control when PE is enabled and disabled, but since the car is driven that way... Trending Topics
08-30-2005, 10:04 AM
#8
I have now done tuning 2 different ways on a recommendation of what I will call a new buddy on here..
I did a 13.0 commanded everywhere..and had no problems... I used the real time command function...not the change the OLFA table method
I also did a 14.63 with PE still enabled...and same results...
for method 2 I set my PE enable to 75kpa with a delay mode set at 0 and enrichment rate set at 4
I also changed my tables for TPS PE to all be 65% so I had a definitive spot where PE kicked in...
For now I am using an ecxel sheet I made to do AFR error % until the HPT 2.0 custom PID's are done....but it works great for me either way...
some say to set the open loop table to 1... I actually just leave the table at its stock value.....It makes sense to me that for our cars the table was set that way for a reason when commanding 14.63.. so I want it to do that too
I just make sure to log comanded AFR along with it to make sure I get the AFR error % correct
I did a 13.0 commanded everywhere..and had no problems... I used the real time command function...not the change the OLFA table method
I also did a 14.63 with PE still enabled...and same results...
for method 2 I set my PE enable to 75kpa with a delay mode set at 0 and enrichment rate set at 4
I also changed my tables for TPS PE to all be 65% so I had a definitive spot where PE kicked in...
For now I am using an ecxel sheet I made to do AFR error % until the HPT 2.0 custom PID's are done....but it works great for me either way...
some say to set the open loop table to 1... I actually just leave the table at its stock value.....It makes sense to me that for our cars the table was set that way for a reason when commanding 14.63.. so I want it to do that too
I just make sure to log comanded AFR along with it to make sure I get the AFR error % correct
08-30-2005, 10:14 AM
#9
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the stock OLFA table still commands 13.0 from map 85-105 from 140*-284*, so if you are gettnig on teh car but you arent really qualified for PE mode and hit those spots of the OLFA table your commanded will change even if the car isnt in pe mode. Another reason for me setting the whole table to 1.0 was to make sure there was no mistake what table the PCM was reading from.
08-30-2005, 10:27 AM
#10
But regardless, the AFR % Error histogram should take this all into account, shouldn't it? So if I'm tooling along the road, and get into PE mode for whatever reason, the percent error is being figured off of whatever is being commanded at each cell (a mix of PE/OL, or all PE, etc), no matter what it is commanding?
08-30-2005, 10:55 AM
#12
Hmmmm...maybe I should just try tuning with PE still enabled. Now here's a question...if I use the scanner tool to lock in the AFR, does that override even PE mode? If it does, then I'm just gonna set my OLFA to 1.0 and leave PE enabled. Just curious...
08-30-2005, 01:27 PM
#15
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it doesnt. PE is used when power enrichment criteria is met and is rpm dependant. The OLFA table is used at all time when in open loop and its axises are ECT and MAP. IF the values are richer in the OLFA when the car goes into PE it will use the OLFA values instead of values from the PE table
08-30-2005, 02:24 PM
#16
What people fail to realize is that there are little garden gnomes that tinker around in the PCM that do whatever the hell they want to without notifying the end-user. It doesn't matter what you tell the OLFA and PE tables to do...it won't. I promise. 
