2006 GT on3 turbo going lean under boost

I have been running this setup for about 5 years now and over the winter I decided to geive it some upgrades. I installed a forged 4.75 stroker kit, ford racing intake, comp cams phaser limiter kit, upgraded valve springs, new ati damper, new level ten 5r55s transmission with 4400 triple disc stall converter. Under boost it goes super lean. I was hoping to make at least 14 to 15psi boost but now I can only run the 5psi spring. If I go for more boost it goes so lean it basically cuts out. My wideband is showing 16 to 1 at 5psi. I dont hold it there I jsut watch it spike. I have a gt 500 pump kit with duetchworks pumps. The fuel pressure holds around 38 psi and pumps are running at 26%. I replaced the maf with a hpx e maf and no change. My tuner is at a loss. When your not in boost a tune change can be seen on my wideband but under boost it doesnt seem to change. We are adding almost 50% more fuel at wot than it should have. Maf tables were updated when maf was replaced. Last year i could run 10psi boost without issues. What could be going wrong.

well if you're sure the pumps are working properly two thoughts:

your injectors are not keeping up or there is a bottle neck in the fuel lines.

have you checked to see if the fuel filter is clear (not clogged) and the injectors are not gunked up?

After I did the build I ran the same injectors before and after the build for break in. Then when I brought it to the tuner and I installed Motorsport 80lb/hr injectors. I did install a new fuel filter too. It had the stock gt500 pumps last year. After I cant get it to not lean out I installed the dw pumps. The pressure sensor is on the stock rails and The pulse width to the pumps is low. It would sure seem that its dropping pressure but from what I am seeing fuel supply is not an issue. I inspected the lines and no kinks or crushed spots. I am ok with installing a return fuel system but I dont think it will fix it.

Immediate thoughts is tune. For physical issue leak around maf or exhaust leak pre 02. But my first thoughts are maf data injector data load for convertor is off in the tune.

Sounds like the fuel pumps are not reacting to the manifold pressure. Fuel rail pressure sensor faulty or not seeing the manifold pressure. Faulty connections at the fuel pump control modules or the fuel pumps. Is it only running on one pump?

I like the fuel pressure sensor not reacting to the boost idea. I will look into that one. The frp always reads between 39 and low of about 36 under heavy load. Should it read higher under boost?

Fuel rail pressure, fuel pump duty cycle and fuel pump voltage should all rise with manifold pressure. What do you have the vacuum line on the FRP sensor connected to?

Its connected to a vacuum manifold block. The same as before. It may have gotten kinked but I'm pretty sure I inspected it. I am at work now but will take a real close look at it when I get home? I have the ford scan tool that I am using to check pid info. Should the PC actually show an increase in pressure or will the Pcm just compensate by increasing the duty cycle to the pumps.

Did tuner update injector data in tune?
Since larger injectors without tune change would result in a rich condition, I suspect injector data is not correct.

He did adjust tune for injectors. The vehicle should have ran pretty good after doing all the updates even without a new tune. I didn't change that much. Engine size went up a tiny bit and I didn't even get to adding boost. It was running 8 to 10 psi and now I go lean at 2 psi.

I got nothing else.
You say there were minimal changes to the tune except for the injectors.

And it is not right.

Unless as it has been said, there is a bottleneck in the fuel flow, all that is left is the injector swap.
Are the injectors what you think they are?

Double check the vacuum lines that are going to the FRPS and double check your fuses and wiring for the GT500 pump kit.

Just to make sure I have it correct, you had the problem before installing the DW pumps, correct?

Were the injectors purchased new or used? As mentioned above, make sure that the part numbers on the injectors are correct for the part.

Beak O Boost said:

vacuum manifold block

Click to expand...

The FRP sensor has to see vacuum and pressure both to work correctly. Also I had my own battle with fuel delivery and it turned out to be damaged connectors and bad connections at the fuel pump hat and fuel pump control modules. I am also running dual DW pumps. When I log with a SCT X4 the PID for FRP runs roughly from 38 to 65 or 70 psi.

I have never seen the fuel pressure go above 40psi. The injectors are new and sealed in box. My tuner said they are the 80 that the box said. Yes it happened before the dw pumps. I unplugged each pump at the pump motor itself and it would still run so I am assuming they both work. Since my pressure never goes above 40 I think I need to address that issue. Thanks for all the input so far.

Are you getting your fuel pressure data from the datalog or from a gauge? I'm using Lito's configuration file for SCT and for fuel rail pressure, mine only varies between 39-41 during a pull, it spikes to 60 as soon as I let off so seeing 40 at the rail is normal. Although the PID says fuel rail pressure, it is actually reading the effective pressure. Ford's returnless system does compensate for seeing boost or vacuum and tries to keep it in the 39-40 psi range.

Either something is preventing your pressure sensor from seeing the boost, or your tuner has a bad value file for the injectors. There was an incorrect value file for the 80 lb injectors floating around for a couple years so I would get your tuner to check that out.

I would check the vacuum block you are using and every hose for damage as sometimes things leak when they have boost pushing them outward but don't leak when they have a vacuum pulling them together.

Hilighted on this log from a 2,3,4 pull in my GT is the PID labeled Fuel Rail Pressure.

Is that read through the factory frp sensor.

Tuners take different approaches. My car was tuned by Lito.
Here is one of my datalogs, you can see the fuel pressure spike as I go full throttle, settle back to 40'ish, and stays between 38 and 44 there until I let off the throttle. It briefly hits 44 as the car transitions into boost but quickly settles back to the range of 38-42 psi. I've taken a bunch of PIDs off this log for clarity but the pertinent information is there.

Keep in mind the OP and myself have turbo cars so the FRPS should be seeing all the boost the car is making. I've never viewed a log from a P/D car but a P/D blower could differ depending on whether you are getting your signal for your FRPS from before or after the rotors of the blower.

Another thing is that Midlife Crises's car pegs the load at 2.0 so tuners will add fuel fueling by upping the fuel pressure since the MAF can't compensate after that point.
I would imagine that the OP's car is similar to mine and has a blow through configuration for the MAF rather than a draw through as well.

Beak O Boost said:

Is that read through the factory frp sensor.

Click to expand...

Yes, right out of the OBD2 port.
Too the best of my knowledge the FRP sensor reference is always after the blower where it will see vacuum or pressure. I don’t see how it could work in front of the blower.