turbo 4.8 silverado injector duty cycle issue

[benloe]

i have a 2001 Silverado with a 72mm precision front mount, isky "triple 12" cam, deatsch works 60lb injectors, areomotive 340, 1218 springs, snow water meth, circle d 2c converter and a 4l80. I am running a 2bar os and the truck runs really good except when I try and turn the boost up to around 14psi or so it will go lean up top and I have noticed that the injector duty cycle will never go above 60% no matter what. I can try and add a lot of fuel up top and the idc will not go above 60, fuel pressure is a solid 70-72 psi wot. my tuner and I have looked through the tune many times and cant seem to figure out why the idc wont go past 60 so any help would be appreciated. I am also having a trans/converter issue that is also stumping me so I will post a trans log also for you to look at and express your opinion on what is happening there. it feels like the converter is trying to half ass lock after the 1-2 and 2-3 shift for a second or so and then it revs normally but this only happens at part throttle, wot it acts fine. converter was just cut and restalled by circle d 2 weeks ago and the trans is pretty fresh with a hd2. sorry for the long post but these two problems have been bothering me for a while and I have tried to fix them myself with no luck, thanks a lot
ben

2001 sd silverado.hpt2-13.hpltrans test 2-15.hpl

[nkautz]

I think your duty cycle issue is that you are actually running on MAF and maxxing it out. It's not disabled properly in the tune under engine diag > DTC's. The first 3 line items should be set to "2- No MIL light" not "3 - No error reported". And also you should zero out the MAF table in the tune just to make sure. Are you sure your tuner knows what he's doing? Cuz that's a rookie mistake. I don't know anything about auto trans, so I can't help you there.

[mowton]

The 2 Bar Custom OS is Speed Density only so the MAF idea shouldn't be in play. What MAP sensor (p/n) are you using?

Who set up the transmission tune? Was it Circle D? Is the TC stall 3200-3400?

Ed M

[2xLS1]

IDC is just the result of a math formula. In order for it to go up either the RPM has to go up or the IPW or both.

IDC = IPW x RPM / 1200

[benloe]

I am using the delco 2 bar sensor but don't know the pn off hand. I did the trans tuning myself and am by no means an expert. The engine side was done by a reputable local tuner and neither of us can figure out why the idc maxed out at 60%.

[nkautz]

The 2 and 3 bar custom OS's do not disable the maf. I ran on maf only with 3 bar OS when I first completed my build. If you do what I said in my previous post , it should fix your duty cycle problem but you'll need to tune the VE.

[mowton]

The gen iv os's do support MAF and SD. The GEN III from what I understand is SD only....

Ed M

[nkautz]

The gen iv os's do support MAF and SD. The GEN III from what I understand is SD only....

Ed M

The car in my sig is the one that I was maf only on 3 bar OS. Stock pcm. Gen 3

[benloe]

I changed the first 3 dtc to no mil light and took it for a drive and when it goes into pe it felt like it was on the 2 step cuz it was so rich. I think I may be headed in the right direction though just need to retune the ve and pe tables. Thanks a lot for the help so far and hopefully I get it running and shifting properly soon. On a side note, does anyone have a good trans test config that they wouldn't mind sharing?

[mowton]

I changed the first 3 dtc to no mil light and took it for a drive and when it goes into pe it felt like it was on the 2 step cuz it was so rich. I think I may be headed in the right direction though just need to retune the ve and pe tables. Thanks a lot for the help so far and hopefully I get it running and shifting properly soon. On a side note, does anyone have a good trans test config that they wouldn't mind sharing?

Hats off to nkautz for the find. Last time I will believe what I read..........why not "MIL on first error" and uncheck SES like normal OS's to get in SD???????

Glad the car is coming around....good luck with the rest of the build

Ed M