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2ktransam
December 8th, 2009, 04:03 PM
I have a weird lean condition when I let off the throttle in my truck and start to decelerate. I'm running speed density in open loop and dfco is turned off for tuning purposes. The only way I can keep it from surging with the throttle closed is to jack up the ve numbers in the low map area below 25kpa to add a bunch of fuel to get it back to 14.7afr. Everything else with my tune has worked fine for two years now but I know that something isn't right with low map area being set to 120% ve when 30kpa and up is normal. Anybody got any ideas? Could be in the tune or mechanical? I have went over everything in the tune a hundred times and can't find anything unusual.
mr.prick
December 8th, 2009, 04:35 PM
Are the fuel injectors stock?
2ktransam
December 8th, 2009, 04:59 PM
Are the fuel injectors stock?

Sorry, I guess I should give some info on my truck.

01 silverado
6.0L swap
turbo
z06 cam
60lb injectors - motrons
mr.prick
December 8th, 2009, 05:11 PM
The minimum injector pulse width may need to be dropped a little.
What is it now?
2ktransam
December 8th, 2009, 05:15 PM
The minimum injector pulse width may need to be dropped a little.
What is it now?

0.592703

I noticed that my cylinder size is set for the 5.3L still. Could that cause this? My AF is good everywhere else but my VE is overstated to compensate for the cylinder size that I forgot to change.
mr.prick
December 9th, 2009, 03:31 AM
I would set that to your actual cylinder size and redo the VE/MAF values.
2ktransam
December 9th, 2009, 06:27 AM
I would set that to your actual cylinder size and redo the VE/MAF values.

I changed the cylinder volume and it didn't affect my fuel settings at all. Weird?
joecar
December 9th, 2009, 06:40 AM
IIRC from a long time ago, the VE table provides the cylinder airmass regardless of the cylinder volume parameter...

i.e. cylinder volume does not scale the VE table.

the cylinder volume parameter is used for information/reference (e.g. when the tunetool displays the VE in % instead of its natural units g*K/kPa).
5.7ute
December 9th, 2009, 11:56 AM
IIRC from a long time ago, the VE table provides the cylinder airmass regardless of the cylinder volume parameter...

i.e. cylinder volume does not scale the VE table.

the cylinder volume parameter is used for information/reference (e.g. when the tunetool displays the VE in % instead of its natural units g*K/kPa).

X2
What is your injector pulsewidth during these lean decels?
2ktransam
December 9th, 2009, 02:47 PM
X2
What is your injector pulsewidth during these lean decels?

I'm not sure. I will have to log it tomorrow and see.