Tuning file installation

[Sam Harris]

They look at injector data. Notice he said “might have a fuel pressure issue” since it’s leaning out. Duty cycle is probably nearing 100% at WOT which means the injectors are staying open as long as possible in order to get enough fuel through. I had that issue with my 12613412 injectors rated at 50lb/ hr but I have a blower and switched to a smaller pulley. At that point I was at the limit of my pump and MAF as well.

Thanks for the info Mark. Yeah, I should have a lot more room to add power, especially since it’s a Flex Fuel motor. My understanding is these injectors should handle more than non-flex as well.

 

[Rocket Man]

Thanks for the info Mark. Yeah, I should have a lot more room to add power, especially since it’s a Flex Fuel motor. My understanding is these injectors should handle more than non-flex as well.

They do. The ones I bought were for an 8.1L flex. I believe yours are 40 lbs/ hr instead of the 28 that the non flex are.

 

[Dantheman1540]

I have flex fuel 36lb injectors and I'm at 90% duty cycle easy to tune as well since they are OEM and there's a ton of data for them.

 

[Tonyrodz]

They do. The ones I bought were for an 8.1L flex. I believe yours are 40 lbs/ hr instead of the 28 that the non flex are.

This is the only reason I wish I had flexfuel.

 

[Rocket Man]

This is the only reason I wish I had flexfuel.

The injectors are cheap, I paid less than $100 for a set.

 

[Sam Harris]

The injectors are cheap, I paid less than $100 for a set.

Nice! Thought they would be a lot more than that.

 

[Sam Harris]

So I hooked up a pressure gauge (actually my mechanics gauge, so it’s reliable)..

Key on: 50psi
At idle: 45psi, but went down to 42psi after idling a few minutes
Drive with the gauge taped onto the windshield:

Never got quite to 50, under WOT, it hit 48-49, but typically stayed at 45-48psi.

So this seems like it’s pretty close to spec, other than the at idle being a bit low.

I’m going to replace the filter (was done 1 yr ago), and the pressure regulator, even though that would typically send the pressure too high of it were bad. See what I come up with after that ..

 

[George B]

I say from experience with the 03 I had thats at spec.

 

[Rocket Man]

What exactly did Justin say in regards to the suspected fuel pressure issue? Too bad it takes so long for them to return an email. They told me they’re 3-4 weeks out on re-tunes right now because so many people are off work and making changes to their rigs. I’m waiting on one for my Silverado as you probably know after my cam swap. I don’t really want to drive it the way it’s running.

 

[Sam Harris]

I say from experience with the 03 I had thats at spec.

Thanks, that’s the same conclusion I met, along with my mechanic.

So Justin sent me a new tune today. He said there’s a default setting that may have caused the lean condition, since I’m running a flex fuel. Installed that, and took a quick drive around. No codes so far. I cancelled my pressure regulator order, and I’ll keep the filter on hand as a spare. Hope this takes care of it!

Thanks @BlackBearPerformance!