Just helped a buddy install a MP112 kit on his 03 SSS. As far as we know the truck is stock with headers and true duals. Doesn't sound like it has a cam. 2.9 pulley gives 6-6.5 lbs boost. Injectors are @100% by 5000 rpm. Fuel pressure drops as low as 32psi at 6000rpm. Fuel is rich at 11.5:1 until around 5000 or so as it gets in the 13's and upper 14's by 6000. Timing is ~15 on the upper end but 9* in the rich midrange and it is still knocking @ 2200 and 3700 as much as 8* KR. It has the add on frame pump from maggie.
Any insight on the lack of fuel, profuse knock and low boost? IAT's were in the 150-175* range. It was hot outside and engine temps ~195*

 

Return style fuel system? How many miles on the truck? Fuel filter been changed? Was the Radix kit new or used? Weak inline pump?

 

Don't mean to sound like a dick, but you DID install the Mag tune that should have come with the kit, right?

 

Sounds like the factory intank pump might be shot

 

yeah, unhook the power to the inline and see what your idle pressure is then.

Obviously the AFR and absence of fuel is causing the knocking, but that boost...even with no fuel, the radix at 6K engine rpm should make more boost. But I'd handle the fuel prob first and then worry about what's left, if anything is.

 

It is a return style system. 30k on the truck, new filter, new booster pump on frame, Kit was bought used off an 06 and has low miles on it. The tune is all custom by myself. I'm not writing off that there is any problems with the tune but this isn't my first FI to tune. Besides everything is in black and white with the timing, wideband, KR etc. on the HPT scanner.
I know the next thing you will ask is for a scan file, well, I forgot to save one But I can get the tune posted up this evening.

I'm not worried so much about the knock in the 5000+ range at this moment because I know it is fueling, i'm worried about the 8* KR at 3700rpm with 11-11.5 AFR, ~55 psi fuel pressure and 9-10* timing. The wideband is a brand new PLX unit. All the grounds from the PLX to the HPT interface are common. I want to put one of my other widebands on it in a week or so when we can meet up again and see if it is just way off, and fix the fueling.
I'll have him check on the pressure with the booster pump unhooked.

 

Check the o'ring on the FPR.

 

beat me too it. bet you that is your problem.

 

He did all the swap of the regualtor stuff. I'll have him look into it.
I just thought of something, The fuel pressure regulator block came with 3/8" quick connects for both the supply and return. Well, the return is 5/16". So temporarily we had to rig a hose using part of the factory rail until he can get a 5/16" quick connect fitting from magnasun. We did our best guess to which side was the supply and return...Those could be swapped but the pressure responds to boost and vacume as it should since it is referenced off the intake. Can someone varify which side is the pressure and return?

 

its almost impossible to plug those in the wrong way.