I put some factory 36# flex fuel injectors in my 1999 4.8 and Im going through hell trying to get it tuned for them. I've been finding bits and pieces of information on them but its still doing terrible. Can anyone send me some files or a link to files that are already on here?
Lookup the 2005-2007 Avalanche/Tahoe/Silverado/Sierra Flex Fuel in the tune repository and copy the injector data over to your tune file and you should be ready to rock. The factory calibration shows 35.4 lb/hr if memory serves. I'm sure your 99 4.8 has the return style fuel system that is vacuum referenced off the fuel rails so you will want to use the 0kPa setting across the entire table on the flow rate and voltage offsets. If you are running a returnless system then copy the data exactly how it shows in the 05-07 flex fuel tables.
The 2004 Flex vehicles used a slightly smaller injector IIRC (33.0lb/hr ??).
James Short - [email protected]
Located in Central Kentucky
ShorTuning
2020 Camaro 2SS | BTR 230 | GPI CNC Heads | MSD Intake | Rotofab | 2" LT's | Flex Fuel | 638rwhp / 540rwtq
2002 Camaro | LSX 427 | CID LS7's | Twin GT5088's | Haltech Nexus R5 | RPM TH400
For some reason I couldn't ever find this thread! The only thing I could get it to idle at was 32 KPA the other day. I'm at work now but when I get off I Will try to play with it some more again and it is the return style. This is definitely not something a beginner tuner like myself should be trying haha
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