Low power on detune..

Nic · Aug 12, 2014

I put the Fuel lab pump on, everything has been ok, it idles a little high due to the old school livewire and the egt sensor. I have one plugged into the rear one but it didn't seem to help it. I detuned it the other day to pull my sxs and it idled normal. But, it was a gutless terd. While it idles around 850-900 in the GH tune, FRP sits at 5.5-5.6. When I detuned it and it ran like a dog, it idled around 5.1 according to the CTS. I have no rail codes and it will hit over 26k easily in the GH tune. However detuned, it ran like it was trying to pull 10k pounds in a Prius. Also, when I slam it (in the GH tune) it seems like it defuels for a second at high rpm then picks back up and bucks a little bit when the TC locks but I dont think the trans is too happy right now anyway. Not sure what to do here.

B585Ford · Aug 13, 2014

Was the only thing you changed the LP system? What is the regulator set at?

Nic · Aug 13, 2014

Yes. Its set at 15psi and I cant get it to go any lower. I believe I need to change up my return lines. I have them together going back into the stock line but I want to run them separate. I think that may be the issue to it holding strong outlet pressure.

Nic · Aug 13, 2014

Nobody knows...

B585Ford · Aug 13, 2014

Nic said:
Yes. Its set at 15psi and I cant get it to go any lower. I believe I need to change up my return lines. I have them together going back into the stock line but I want to run them separate. I think that may be the issue to it holding strong outlet pressure.

Return lines from where...cooler? banjo? Do you still have your fuel bowl?
Have you tried measuring the pressure at the shrader on the cooler?

Nic · Aug 14, 2014

Talked to a guy referred to me. I guess from what I understand should have done a fuel bowl delete. The way I set it up was I cut the supply and return in front of the factory pump on the rail, removed it and ran the supply from the fuel lab to the supply line i cut.

I then tee'd in the return line from the fuel lab to the line i cut and then back to the other return line to the tank. So basically the fuel lab and the facotry return from the engine are sharing the return to the tank. This is a problem I believe becuase not only is it not letting my supply pressure go down, theyre sharing a 3/8s line back to the tank. Im going to go ahead and make the return line at the Fuel lab go 1/2 in back into the filler neck and tie the factory return line back to itself. This will most likely cure my pressure issue but I'm afraid of my low power issue when its detuned still.

I was told it could be a few different things and I'm hoping I haven't already done damage to the hpfp. I was told something about a reset on the fuel adaptive cables? Not sure on that or what that is. SO, I will start with fixing my return lines, return the truck to stock and take it back to PSM for a full Diag on the truck.

B585Ford · Aug 14, 2014

The devil is in the details....now this makes a lot more sense. The reset is just like tranny learning only for the HPFP. I am not sure if it is necessary...cause I have seen several guys say never reset it when they did LP system changes and even HPFP changes. The only time I messed with my fuel system I made changes to both. IDS can do it and I think a few others like scan gauge.

powerstroked08 · Aug 14, 2014

Keep us update on this Nic. I'm curious on the outcome. I hope the return reroute fixes your issue!

CT9AIX · Aug 14, 2014

I've got the return from my Fuelab tee'd into the return from the engine with no issues. My return line from the engine is a 3/8" line straight from the rails/HPFP straight back to the tank... I removed the fuel tank and got rid of all the crap factory plumbing. I also never did any type of reset with any mods on my LP fuel system and it has ran perfect for 20k+ miles. Don't know if this helps narrow things down at all for you

Nic · Aug 15, 2014

Well I hope its ok after this. It was really strange having that low power in stock. Idles fine, starts fine and drives fine. Kicked it back in the tuning and she screams. Hit 26k+ with no problem tuned. Just worries me. I'll keep this updated as soon as I get the returns fixed.