What year is your truck? Did you decide on a wideband yet? With as much as you have invested I wouldnt slack on the tuning tools. You can pick up HPTuners for $499 and the LC1 for $175. Otherwise you are going to be in this situation everytime you want to pulley down or change something. Im permanantly installing my LC1 with an XD1 in my truck. Not sure how far you are, but Ive got a liscense for an 01 Tahoe if that will work to load your file. Im in Brandon

 

Mines an 02. I'm from Lakeland but stationed in the panhandle, near Pensacola. I am pretty sure I'm gonna buy HPT and a wideband that works with it. I will do this after Christmas. I am still working with a local tuner and a mail order guy who are helping me out. I have to get an inline fuel pump in first. My pressure tries to drop above 3500rpm. I have not been WOT since the install.

 

New question.

Stock fuel pump and 42# Ford injectors. My fuel pressure goes to 62 as it should when I give it over 50% throttle. When I get to the top of the rpm range the pressure falls off to 55 or so and at the shift, shoots back to 62...slowly falls back to the 50's then on the 2-3 shift, back to 62. After I let all the way out of it it drops in to high 40's and slowly builds back up to 50. (Mine sits at 50 at idle, Flex Fuel truck)
Why does it do this? Because all the load is off the engine for a moment during the shift and the pump has time to pressure up the fuel rails again? Wondering what you guys with fuel pressure gauges see on a day to day basis? Does your pressure stay at 62 or whatever and not move or does it fluctuate a little at shifts and on top when your giving it a little gas?

 

Mine stays at 62 most all the time. Mine may drop just a few #'s in the upper rpm band when more fuel is being demanded.

 

The 04+ have a returnless fuel system and they do not work the same as the 99-03. The pressure regulator is in the tank with the pump and a constant fuel pressure is maintained. The 99-03 have a pressure regulator on the fuel rail on the driver's side with a vacuum/boost line going to the intake manifold. My truck runs about 52 psi at idle, 49 on deceleration (high vacuum) and 58 psi under normal acceleration and cruise. On WOT my truck runs about 62 psi and 67 psi or so under full boost. I have the in-line 255 lph Walbro pump and my fuel pressure does not drop off as revs build.

Have you got your in-line pump installed yet? Get-r-done.

I have the regular fuel system but I think it works the same. AFAIK the flex-fuel system just has all parts designed to be chemically compatible with the alcohol or whatever is in the alternate fuels.

 

MIne with stock pump would act like Morts but on the nitrous it would slowly come down from 62ish down to like 56 when it was stretching out through 2nd up to 100 where I shifted inot 3rd. I owuld imagine that this is what you are experiencing with fp drop but with all the fuel yoru truck is demanding you need to get that inline pump in

 

I have the pump and am hoping to get it in tomorrow. I don't really know the differences in the FF and regular fuel trucks except I was told with the basic Radix kit I did not need the inline pump. This leads me to believe the pump flows a little higher than non FF. I also did not have to upgrade injectors, FF come with 34#. Now that I'm doing all this I want to make sure I am doing it right. My truck sits at 50 at idle. Goes up to 55 or so if I'm just normally taking off. Goes to 62 at wot, regardless of boost level. Never goes above 62. I'm replacing the fuel filter and putting on the inline pump tomorrow I hope. See what happens. Oh Yea, got the Predator shipped back today and if that doesn't work out BigKid has offered to help me get the tune tweaked. Hoping to have her all fixed up by Saturday.

 

What does an exhaust leak sound like? Since I put in the 6L the exhaust note is really loud. Loud as in drone while running up through 3rd. As soon as it hits OD the sounds cuts in half and sounds almost stock again. This is not when I get on it. I am talking about a 25% throttle take off from a red light through the gears nice and easy. So loud I can't talk normally to someone in the pass seat. I crawl under the truck and cant smell or hear anything at idle. I just dont think it could have gotten that much louder with .7 cubes. Ideas?

 

Have some one stuff a rag in the tail pipe while it's idling. The you can really hear if you have a leak much better.

 

The increased valve duration is what makes it louder.My truck got alot louder with a big cam.