99 2nd gen 2wd dually. 365k miles. Bonestock besides 4" straightpipe, S&B Intake, and quadzilla adrenaline V2. In the video, I'm running the "stock injector race tune" from me78569 that i downloaded from here. 

 

Turned all the way up to 5:

Im maxing out at 19psi of boost.
My fuel pressure sporadically spikes down to 7psi.
And the truck doesnt blow any smoke (not that I care, just concerned it's running lean because i feel like it should be fueling for 35-40psi from what I've read)

 

Any idea what's wrong? MAP sensor? It acts like this even in the default power levels, cranked up to 11. No CEL, but I am getting a p1693 code on my CTS2 monitor. 

4 hours ago, Dieselfuture said:

It's probably your ball and spring in the return of Fass to tank. Common problem. Also do you have a needle valve before pressure gauge to regulate pressure swings and keep the gauge from being damaged

Yes the quadzilla Fp sensor comes with the snubber 

 

56 minutes ago, hdpwipmonkey said:

I'm not sure about that.  When my pressure was fluctuating because of the ball and spring, it didn't sound like that.  Not saying thats not the issue but to me it sounds more like its sucking in air or the pump motor is bad.  You can try the spring and ball if you want.  They are cheap and easy enough to change out.

My sump is leaking slightly due to my own ignorance. I didnt put it on a flat surface. But the pump sounded that way before I installed the sump which was almost 2 weeks after. I have the same one in my chevy and I've always thought this one sounded odd compared to it. 

21 minutes ago, Mlhiser12 said:

Yes the quadzilla Fp sensor comes with the snubber

Snubberis a good start but without niddle valve it will still bounce fast on the gauge like in your video.  

I'm running 7x009 injectors. Turn buckled waste gate and boost fooler seen psi as high as 38 pulling grades towing.

Egt down noticably compared to pulling grades with waste gate open bouncing at 21ish psi.

 

But backing off throttle cause turbo making a hellashish screaming sound at 38psi.  Stock hy35.  

 

I replaced stock injectors at 220k area

They were very dirty carboned up. Fuel spraying through thick carbon tracks.

 

Truck was like night and day dropping in 7x009 eac injectors. Even at 20lbs of boost. No boost fooler on mass airflow sensor and waste gate opening. 

 

You might pull injectors and clean nozzles or replace them. I bet you might see a seat of the  pants improvement 

 

 

Figure the problem out finally. At some point, someone plumbed in a auxiliary pump for a fuel cell in the bed. they mounted it out of plain sight where you wouldnt  see it unless you were looking for it or you traced the lines. 

 

Essentially the factory return line was running to the aux pump, which ran to the non existant tank pump which is capped off. I tore the 366445 feet of hose they installed and hooked the factory return back up where it was originally and it runs like a top. 

 

My sump was never leaking either. It was the return hose the whole time which was just laying on top of the tank, dripping down the inside of it, and falling from the sump. 

 

All in all, I'm an idiot and shouldve noticed this hack job of hoses and wires.

 

To the fella who put this all in, I hope it burns when you pee.