03 2500 hd questions

[jason k]

hi i have a small list of questions first off I am tuning my 03 2500 hd truck it has a 6.0, stock bottom, end small cam texas speed 216/220 @.050, 550 lift, 110 lsa, stock small chamber 5.3 heads, shorty headers, stock intake manifold, tb, and stock air intake 4l80e 4:11 rear and 35 inch tires it is a daily driver / plow truck and i dont really tow much at all
I have my gotten ve table dialed in a bit then I tuned my maf also checked my WOT with my widebands its all close enough to drive and be safe
1. First question i am working on PE and i see the trucks dont command PE until 90% tps hot and cold also stock delay is like 60 seconds and 5500 rpm delay and a slow enrichment rate. Should i leave this all stock or command it to something normal like 0 sec delay 1500 rpm and 1.0 enrich ramp?
2. should i mess with open loop fueling?
3. when in closed loop and not in PE are MAF and VE tables the final say in fueling? i ask because at high map (55kpa and over) and low rpm (2000 rpm) I am commanding 14.7 afr and i think something lower like 13.0- 13.5 would be better
4. after a road test and scan I see i logged at one point 2450 rpm MAF hz was 6750 and MAF 92.40 g/s when i look at the tune MAF hz @ 6750 is 90.82 g/s should i add the 2 g/s to that reading?
working on it.hptthursday nite wot with wideband.hplworking gen 3 truck layout.Layout.xml
been a long time since i posted a log or tune hopefully its correct
thanks

[5FDP]

1. Make it all lower. Do 65% throttle, 0 seconds, 1,500rpm and a faster enrichment rate.

2. No.

3. The computer will always command stoich in closed loop. So you can't make it run richer at 13.0-13.5 when in closed loop. If the MAF/VE are tuned right your fuel trims will show roughly ~5% off zero while driving. If the trims are still way out then more work on the MAF/VE is needed so it's not doing as much work.

The timing at full throttle is pretty low too. It should pick up a lot of power if it's not running 12 degrees of timing. Should be able to get at least 20-24 degrees from a cammed 6.0.

[jason k]

1. Make it all lower. Do 65% throttle, 0 seconds, 1,500rpm and a faster enrichment rate.

2. No.

3. The computer will always command stoich in closed loop. So you can't make it run richer at 13.0-13.5 when in closed loop. If the MAF/VE are tuned right your fuel trims will show roughly ~5% off zero while driving. If the trims are still way out then more work on the MAF/VE is needed so it's not doing as much work.

The timing at full throttle is pretty low too. It should pick up a lot of power if it's not running 12 degrees of timing. Should be able to get at least 20-24 degrees from a cammed 6.0.

thanks for the reply
is stoich ok during part throttle cruise?? most things i read always say 13-14 for part throttle cruise. I am little nervous on this one i built the engine about 80,000 miles ago and never was impressed with the cam choice/ power the truck made. recently it broke a valve spring, on tear down i found 6 burnt exhaust valves, and cracks between the seats, definitely lean. So I dumped the 317 for a set of 862 off a 5.3 with a fresh valve job i tuned it myself years ago horribly I might add, but it ran ok so .....now that i look at it after 5 years of messing with my own tunes i just started over from stock also why the timing is so low right now heavy truck and a decent bump in compression also has me cautious

[5FDP]

is stoich ok during part throttle cruise??

Yes. You have no other choice if you want to run closed loop. Every single factory vehicle runs stoich at part throttle cruise in closed loop. That doesn't change for modded engines either. It's a minimal load situation, it doesn't need to run 13's as that would just be wasting fuel.

[jason k]

ok thanks for the help