Ok mods are in my sig. Im just trying to learn about efi and tuning, etc. This is my first vehicle that wasnt carbed and its still greek to me.

When tuning my truck, it had stock manifolds on it. a few days before i installed my longtubes.

My buddy mentioned that my injectors are maxxed out at 110% duty cycle. It just kept taking and liking more fuel. They cannot add anymore fuel than they already are when its demanded. Mentioned I can send them off and get them reflowed or upgrade to a larger set, etc.
Since the LT install it was reflashed but this remains the same.


My question is this, How common is it for my injectors to be maxxed out at 110% duty cycle with my mods. This may be very common but i was just really surprised at this. I kinda figured this wouldnt happen until I crammed some air into it.

i dont have a graph or datalog for you to look at but the tuner is very knowledgable and the truck runs awesome and gets pretty good gas mileage to boot, well until my stall install last week. lol

 

I've seen it quite a few times when the tune is off and the injectory duty cycle is inflated by quite a bit. A stock 6.0 with nothing but longtubes shouldn't be at 110% IMO.

 

I've never seen 110% IDC with a setup like that. The wide open throttle portion of your tune was done with a wideband hooked up right? If so what was the Lambda/AFR at WOT?


My guess would be the tune is pig rich and thats why you are seeing that. What AFR are you commanding in power enrichment, at WOT?

 

Are you still running on the factory 5.3 Tune???

 

Low fuel pressure(weak pump) would cause this problem also. Get a fuel pressure gauge on the truck and watch for pressure drop. I hope you're tuning with a wideband, or know what you're doing with fuel trims, so you don't just tune it pig rich.