Odin

UPDATE: Nissan has now told me that my ignition is cutting out at around 4500-5000 rpm. Where I know my injectors are maxing out. Should I get new coils? I'm starting to kinda take for granted when they've told me before. Im gonna replace my coils anyway for peace of mind. However, i feel as if this is not the root cause of my issue.

SonicVQ

As you will soon see, this may have taken an interesting turn.....

Interesting points to note:
(1) Nissan says the ignition is cutting out
(2) I know my injectors are maxing out.

Could these be related???

In the voice of Jeremy Clarkson: Yes!
If a cylinder misfires (ignition cutting out), the oxygen in the cylinder is not burned, it rushes past the O2 sensor and it sees a whole bunch of oxygen and reports a lean mixture to the ECM.
The ECM then increases the injector duty cycle to add fuel and waits for the next O2 report.
You might want to have a look at the mode $06 misfire counters (OBDFustion is best and is shown under diagnostics) to see if the ignition is cutting out (ignition cut out/malfunction = misfire)

-OR-
The other option may be a weak fuel pump.
The graph below is from your second data log (3rd gear run).
As the RPMs increase, after about 3,100 RPM, your fuel correction goes to 125%, and your air/fuel ratio is getting DANGEROUSLY LEANER...
At 4,600 RPM it is 15:1, which is leaner than a proper idle. From there it gets a lean as 19:1 at 5550 RPM!!!

MAF air flow looks good.

(top to bottom: Engine RPM, Air/Fuel Correction, AFR (B1), MAF flow (g.s)



How does Nissan know your coils are cutting out? Do you know what test they did?
I don't think it is your coils. If you had a misfire, your CEL would flash and most likely set a code after the misfire threshold was exceeded.

My next step would be to measure fuel pressure (you or the tech will need a fuel tap (https://cj-motorsports.com/products/fuel-tap-npt-2-bolt) and a gauge.
Idle should be around 51 PSI.
You should also check the fuel pressure under high engine load on a dyno, or use a 100 PSI electronic sensor and gauge to see the pressure while data logging your next run.
*** By the way, you should minimize full throttle unless for testing. Your fuel system seems to be VERY lean and that is when pistons start to melt, and valves burn. ***

Surfnazi

Swap out injector with another one and see if problem follows it

Odin

Update: I got new spark plugs. While the car feels a lot better. There's still the issue present. However, I believe the issue is now happening at a higher rpm than before.
I've also noticed that if I use anti-lag/2step before I do the pull. It will respond a lot better. Not sure if that means anything but worth adding. Attached is my latest log. I'm somewhat learning how to read it. My A/F Ratio goes up to 125 then back down to 75. Im not sure what it entirely means but it looks like it trys to correct something and then stops again? INJ DUTY still getting up there but not as high as before.

I got the OBD Fusion app to test test the car and it raises no concern and everything has a check mark in the $06 .
I have ordered the Fuel Tap but I may get the electronic one to test under load. Maybe I should just get a new fuel pump?

Odin

TL/DR : fuel pressure bad, how fix?

I have just installed a CJM Fuel Tap and ran a AEM Fuel Pressure gauge. Upon doing my test pull, the pressure drops to 7-14psi! After some advice given to me on here, thats lethal.

Which brings me to a roadblock. What controls the pressure on our cars? When researching a fuel pressure regulator for our cars nothing pops up but the fuel injection dampener. IDK if this is an issue with my pump, since just recently i replaced it with a new assembly (used)

Its possible that both (new and old) pumps couldve been bad , i may replace the dampener just to rule it out. If theres a Fuel Pressure Regulator does anyone know where it is?

Birdie

Which fuel pump are you running and did you install it yourself?

Odin

​​​​​​​Just another stock Fuel pump assembly. It was off a 08 G37 just like mine. I installed it myself.

Birdie

I would recheck it to make sure the clip is on right or its getting enough power.
I have a used used one that I know is good along with some fuel injectors.

SonicVQ

You have questions, I have answers
(1) Fuel pressure under wide open throttle at high RPM should still be > ~45 PSI (stock engine & pump)
(2) The fuel pressure regulator is part of the fuel pump assembly aka "basket" Generally they

Now, my turn for questions:
(1) What is the fuel pressure at idle?
(2) Are you sure the gauge is accurate? I would think with 7-14 psi the engine wouldn't be able to make any power or rev high.

As for the fuel damper:
Unless something has broken off and got stuck inside the fuel damper, it has almost no impact to fuel flow.
Its single purpose is to reduce (dampen) high and low fuel pressure spikes.

If this was my car, my next step would be to use a current clamp and measure the current of the running fuel pump.
Stock pump at idle is about 4 amps.

Do you have anyway of measuring current?

Odin

I have a DMM that i can use, however measureing while on the go might be tough. At idle, its at 50-51psi. I can rev high if i press the gas slowly. Itll hit rev limiter with 45-48psi. While driving normally, i can see it hit as low as 36psi.

only at WOT, or if i press the gas past half way will the fuel psi diminish.

Edit- just seen you said to measure at idle. I will do so and post again. you def helped by letting me know that there is no external assb.

SonicVQ

What is the voltage at the pump when at idle?

Just to clarify:
• The original fuel pump the pressure was ~15 psi during WOT
• The used replacement is also ~15 psi under WOT

I wouldn't think TWO fuel pumps would have the same problem as they are generally very reliable.
Did you do as Birdie mentioned and double check the fuel supply tube's clip to make sure it is fully seated?

If you removed the tank cover and started the car you could visually check for leaks at that connector IF the fuel level is low enough.

Odin

So after driving the car with the top of the fuel pump exposed, the hose for sure makes a leak sound. While im driving I pulled the hose onto the nossle and the sound went away. I havent confirmed if the pressure went up after holding. I hope its the green tab. Im gonna try to replace it if possible.

update- after driving with it open some more, the leaking sound isnt there anymore, more or less, i can here the pump doing its thing.

Birdie

Can you check it at idle. sucks playing the guessing game. Are the wires all the right gauge?just asking because I know you replaced the pump already and I'm hoping you didn't reduce the wire size as the pump needs to hold the proper current. I'm hoping you are getting close to solving your problem

Odin

I just installed DW200 Fuel Pump in my original housing assembly. At idle the fuel pressure still is normal. With the new pump I idle at around 55-60psi. I was getting 45-51psi with the stock pump. However, under load, pressure is still dropping under 20psi and even as low as 12psi.

Might remove tune to see if issue persists on stock ECU. No weird sounds coming from fuel pump. No fuel leaks at dampener or fuel connection at pump.

SonicVQ

You have tried 3 different fuel pumps and still have low fuel pressure under load. I don't think it is the pump.
I assume you are using the factory wires, so they should be ok.

It is not your tune. The stock fuel system can provide enough fuel flow for the typical intake/exhaust bolt-ons.
(based on my calculations, the stock fuel system can support up to ~330 wheel HP)

If this was my car I would measure the voltage and current at the fuel pump while under load.
This does require special tools, but I think the next step is to verify the electrical side.