Fuel pressure drop in boost

[topekamk3]

Alright everyone it's been awhile since I've posted on here but I got my build complete'd and have finished breaking in the motor. Now I'm starting to work on tuning it, but as soon as I go into even low boost (2-4psi) the fuel pressure drops all the way down to 15-20psi. I've tried adjusting my base pressure, with vac unhooked had it set at 38psi, 44psi, and 50psi but still does the exact same thing. It had been working fine for the 1st week or so but since then has been doing this. I also thought it might be a fuel pump issue so I sent in the one I had as defective and got a new one but it still does the same thing. Here are the specs to my build:
7m-ge(na->t)
Eagle Rods
JE .40 over Forged Pistons
JE Proseal Rings
Driftmotion Shimmed and Moly-Coated Oil pump
6m Crank, balanced and knife edged
Brian Crower Titanium Retainers and Valve Springs
Titan Motorsports 2mm Metal Headgasket
Arp Undercut Headstuds
Arp Mainstuds
All lightweight aluminum pullies(crank was balanced with it on)
All 7mgte electronics
Garrett Turbo T04E17
Tubular Divided t4 Turbo Manifold
Ron R. Front Facing Intake Manifold
Solid Motor Mounts
Spec Stage 3+ Clutch(up to 450ft. lbs torque)
NGK Plug wires
2 Step Colder NGK Spark Plugs
EGR Deleted
E-vac setup(removes standard pcv system)
Alternator Relocate/AC Removed
CX Racing FMIC
HKS BOV
B&M Racing Oil Cooler
Power Steering Cooler
Walbro 255lph Fuel Pump(inline)(12 volt mod done)
22 Gallon Jaz Fuel Cell
AN-6 lines from tank to fuel rail and back
AEM Adjustable Fuel Pressure Regulator
Precision 550cc Injectors
Glowshift Water Temp, Boost, and Wideband intergrated into the stock cluster
Glowshift Oil PSI and Fuel PSI
3.5" Exhaust
50mm External Wastegate
GM Map Sensor and AIT Sensor
Running MAF-Translator Pro in Speed Density Mode w/ Timing Control
4.30 Rear End Gearing w/ LSD
w58 Transmission

 

[radiod]

When you pulled the fuel pump was the sock dirty/clogged at all? What about the in line fuel filter? I know they are designed to last a very long time, but it's still possible for them to get clogged.

 

[topekamk3]

There's not a sock anymore. I have a fuel cell setup with an inline walbro pump and all new an lines. The fuel filter was brand new with the fuel cell and pump so have maybe 100 miles on them. I went to the fuel cell setup because I dropped the tank to install an intank walbro 255 and the tank was nasty inside. So didn't want to use any of the old tank, lines, filters, or anything.

 

[3p141592654]

Monitor pump voltage during operation. The FP terminal on the diagnostic connector is one way to access the voltage conveniently.

 

[topekamk3]

Oh I forgot to mention, I've done that as well. I actually hooked it to the positive and negative studs of the fuel pump since it's inline and I have it mounted in the back hatch area. I'm right at 13.1-14.2v at all times. I also unhooked and plugged the vac line that controls the adjustable fuel pressure regulator and ran it that way to make sure it wasn't an issue with the raising ratio part of it and still did the same thing.

 

[topekamk3]

If anyone has any other ideas, please let me know. I went ahead and have a new inline filter coming in. It shouldn't be plugged already but it's something that's worth a try and doesn't hurt to have a spare laying around either.

 

[kotu100]

I'm having this same issue with my car, dont really have any suggestions for you though.
Looking forward to a solution, hopefully we have the same thing causing the issue.

 

[Nick M]

Is fuel flow dropping in boost?

 

[Albert]

Billy had the same issue. Clogged pickup on fuel pump.


I had the same issue, kink in feed line by filter.

Sounds like a fuel starvation issue to me

 

[topekamk3]

It was fuel starvation. Clogged fuel filter. Note to anyone using fuel cell foam, get a spare filter and switch it out after the first couple weeks. As you see in the picture just build up of particles of the new foam. I was running a pretty small inline filter so didn't take much to clog it. I went ahead and switched to a bigger filter.

 

[Albert]

1 point for Albert

 

[topekamk3]

Not to discredit you, but check 3 post above yours. I do appricate the response though.

 

[Albert]

Still called it before it was replaced

 

[topekamk3]

Still called it before it was replaced

Touche, though I actually put it in on Friday, I was too busy tuning to post until late Sunday. From the sounds of it it's pretty common, but I couldn't find anything from searching about it.