I'm finally getting around to putting the NNBS intake on my crew and while I'm at it I'm swaping the 6.0 injectors out to some of the older flex fuel injectors. The new injectors came out of 03 tahoe l59. I was able to find an 04 on HP tuner's repository but I think the tahoe had a return fuel rail which has different flow rates than a non return. Here is my current tune in which I copied the values from the repository. Will this work?05 ccsb 12.hpt

 

I have been busy doing CNG conversions for the last 6 months or so. I see no end to them, but I have a few files

 

Thanks again Caleditor,you have been a lot of help to me. The injector values in those tunes match the one I got from hptuners repository...but I think I need the values from a returnless fuel rail set-up. They are different arent they??? Thanks

 

The 04 should be a returnless system
I have a few more

 

I don't see why a returnless would have different values. If the fuel pressure is the same at the rail, everything would match. Unless I am not thinking about it right.

 

Flow rate vs KPA is different on the returnless... It ramps up. It is a set value of 33lb on the return style rails. This is what I have seen in the various tunes I have looked at regaurding flex fuel injectors. Can someone verify this??

 

The values are not the same. You have to have different injector values for different manifold vacuum. You have to tell the injector to flow less when there is more vacuum sucking fuel out of the rail. When you are in boost, it is just the opposite. the boost will push the fuel into the injectors so you have to tell the injector to push harder.

 

Oh ok, I didn't know the return style was referencing vacuum/boost, and the returnless wasn't.

You could easily figure that by finding your kPA at key on engine off. Then use that value across the board.

 

I ended up using the 05 tahoe injector values.Hooked up the wideband and I was rich in pe mode 11.2 to 12.0 so I backed of a little in the pe table.Got it to about 12.5 now from 4000 to 6000. It has a little flat spot in the transition to PE mode,should I ramp it down? I can def. feel a SOPT gain from the intake and 90mm just gotta do a little fine tuning.