holty i am an 04 truck and when im at wot i see it get to about around the high 50's at wot but i am at 60 + at idle. i have the magnacharger intank pump with the ford svo 42;bers( 50 lbers @ 60 psi though. my wideband is syaing im arouns 12.13.1 at wide iopen too . its just very hard to watch fuel press and wideband when im wot. let me know if you have any more questions i know we have different fuel set ups but id like to have 60+ psi at woth also

 

I think your idle fuel pressure and WOT is fine (except for the drop) I sit at 48-50psi at idle and about 60-62 WOT. I'm not sure how the return system works. Is there a check valve that could be bad? Do you have a boost/vacuum referenced FPR? What size injectors are you using? If they have gone static at WOT because of 100%+ IDC that may account for the drop. All your injectors are staying open. Just throwing out ideas....

Good thread on my theory....
https://www.performancetrucks.net/fo...+injector+duty


Here is the formula to calculate injector duty cycle:
%duty cycle = {GM.IBPW1}*{SAE.RPM}/1200 (EFILive PIDs)
or %DC = base pulsewidth * RPM / 1200

 

i say from listening (reading) from many others that are return systems that even at 100%+ IDC you should keep your fuel pressure psi. pressure isn't volume. with that in mind if he is really suffering from IDC starving his engine, he'd see a good psi but a lean condition. He is seeing an unstable psi at wot. I may be wrong (the wife will atest to that happening ALOT) but something else is going on here IMO. His mileage doesn't say the stocker is bad (27K) but it is possible. It's his 2nd inline as well. I tell ya what I want to know, what the hell is the magnacharger inline.? What is its rating? I thought it was 255 lph but i have heard it isn't that. WTF.

you have the same fuel system as WHippled just different demands. He has a radix and it has the 42lb'ers. He does have an issue with IDC and that could very well be his problem, I just don't think he should see such an unstable psi, no matter the IDC. (except extreme cases of 110%+)

2004SSS, what tuning software do you have?

 

i will return to this in the morning. i was driving around today after work and noted all my fuel pressures at various states. i'll post back tomorrow.

 

I "would" have had a radix if they made them for the 8.1L, but they dont. I have the Whipple. You have hurt my feelings now DEW, i thought you knew me better than that..... its my screen name for petes sake...LOL ...have another beer on me.

 

Who at magnuson told you a walbro 255 would work? It would take some major work and hacking to make it work in the return system fuel basket. I had fuel pressure drop problems too and replaced the stock fuel basket with fuel pump and my drop went away, but i also had 95,000 hard miles on it.

Check to make sure fuel filter is installed to arrow of flow. GM filter only.

I have a magnavolt and 60lb. injectors. I have 60 psi WOT 50 psi at idle and more fuel than i know what to do with in the tune.

Hope this helps, Tony

 

settle, i think i typed it wrong. All I am saying is Holty has a Radix and 42's, didn't someone ask what his injector size was. I didn't mean YOU have a radix...I recall you saying you wanted a radix. I know your story. Sorry for the misunderstanding.

btw, it was vodka last night.

 

hehehe, I love it when BS gets called.

I think it was a rep for Maggie Tony. Holty will post up I am sure.

 

LOL...just fartin with ya anyway....

 

i know i know, just got the vodka hazziness going this morning.