Fueling & Injection Fuel Pumps | Injectors | Rails | Regulators | Tanks

Need help fuel psi drops under accel!

Thread Tools
 
Search this Thread
 
Old Mar 29, 2009 | 04:56 PM
  #1  
camaroIroc's Avatar
Thread Starter
Staging Lane
iTrader: (1)
 
Joined: Apr 2008
Posts: 95
Likes: 0
From: Denver/Charlotte
Unhappy Need help fuel psi drops under accel!

i have a 5.3 with an ls6 cam tuned. Aeromotive regulator and walbro 255lph pump. Plummed all the way with 3/8" push loc, no leaks. Billet rails, ls1 injectors. Fuel filter is new.

My problem is that when i push the throttle, my psi drops way too much. I have it set at around 58-60psi at idle, but it goes as far as 0psi under wot. What should i do now?

I have a 17gal cell none sumped, the pickup is in the tank pulling from the top, maybe i should get a sumped setup? Or something else?

Any help is appreciated!
Reply
Old Mar 29, 2009 | 06:16 PM
  #2  
camaroIroc's Avatar
Thread Starter
Staging Lane
iTrader: (1)
 
Joined: Apr 2008
Posts: 95
Likes: 0
From: Denver/Charlotte
Default

anybody??
Reply
Old Mar 29, 2009 | 06:41 PM
  #3  
98Camarod's Avatar
11 Second Club
iTrader: (43)
 
Joined: Aug 2006
Posts: 5,364
Likes: 2
From: Summerville, SC
Default

Is there another regulator in the tank?
Reply
Old Mar 29, 2009 | 06:57 PM
  #4  
camaroIroc's Avatar
Thread Starter
Staging Lane
iTrader: (1)
 
Joined: Apr 2008
Posts: 95
Likes: 0
From: Denver/Charlotte
Default

nope...
Reply
Old Mar 29, 2009 | 07:08 PM
  #5  
98Camarod's Avatar
11 Second Club
iTrader: (43)
 
Joined: Aug 2006
Posts: 5,364
Likes: 2
From: Summerville, SC
Default

It drops to 0 or is that a typo?

Do you have the regulator after the rails? Do you have any pictures of the fuel system setup?
Reply
Old Mar 29, 2009 | 07:14 PM
  #6  
camaroIroc's Avatar
Thread Starter
Staging Lane
iTrader: (1)
 
Joined: Apr 2008
Posts: 95
Likes: 0
From: Denver/Charlotte
Default

this is my setup, should me return line be routed off the back of the second rail instead of the original spot under the fpr? i cant think of anything else.

Reply
Old Mar 29, 2009 | 07:16 PM
  #7  
camaroIroc's Avatar
Thread Starter
Staging Lane
iTrader: (1)
 
Joined: Apr 2008
Posts: 95
Likes: 0
From: Denver/Charlotte
Default

the more throttle i give it, by hand of course... the lower it goes and starts to stumble and fall on its face. 0 psi is no typo very close to it.
Reply
Old Mar 29, 2009 | 07:22 PM
  #8  
camaroIroc's Avatar
Thread Starter
Staging Lane
iTrader: (1)
 
Joined: Apr 2008
Posts: 95
Likes: 0
From: Denver/Charlotte
Default

the only real answer i see coming is the pickup tube being restrictive under load...its kinda like a straw affect...maybe?
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

 Pouria Savadkouei
story-1

Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

 Verdad Gallardo
story-2

7 Most Reliable High-Performance Engines GM Has Ever Built

 Verdad Gallardo
story-3

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

 Verdad Gallardo
story-4

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-5

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-6

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-7

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-8

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-9

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
Old Mar 29, 2009 | 07:22 PM
  #9  
98Camarod's Avatar
11 Second Club
iTrader: (43)
 
Joined: Aug 2006
Posts: 5,364
Likes: 2
From: Summerville, SC
Default

Since you have the regulator, I would run the feed to the rail, run the cross over, then go to the FPR, and block off the other side. This puts the regulator after the rails making it a return system. Make sure that your tank is vented or has a way to vent.
Reply
Old Mar 29, 2009 | 07:27 PM
  #10  
camaroIroc's Avatar
Thread Starter
Staging Lane
iTrader: (1)
 
Joined: Apr 2008
Posts: 95
Likes: 0
From: Denver/Charlotte
Default

i have a roll over vent.. does that normally vent until its upside down right? lol i can change my setup to the way your saying... i am thinking of also getting stock rails too.. those billet ones i got have acouple minor accumulations around the fittings of fuel. just cant get those npt fittings to seal up good.
Reply
Old Mar 29, 2009 | 07:31 PM
  #11  
camaroIroc's Avatar
Thread Starter
Staging Lane
iTrader: (1)
 
Joined: Apr 2008
Posts: 95
Likes: 0
From: Denver/Charlotte
Default

like this?



i guess the only bad thing is i cant really get a stock ls2 rail... it is not a return style
Reply
Old Mar 29, 2009 | 07:34 PM
  #12  
98Camarod's Avatar
11 Second Club
iTrader: (43)
 
Joined: Aug 2006
Posts: 5,364
Likes: 2
From: Summerville, SC
Default

^^Thats right. I had to use quite a bit of thread tape on mine to prevent them from leaking. I'm not sure how the vent works, post up how it works out.

I think the way you have yours set up now is wrong and it works fine at idle, but it bleeds the pressure off when its changed demand.
Reply
Old Mar 29, 2009 | 07:37 PM
  #13  
camaroIroc's Avatar
Thread Starter
Staging Lane
iTrader: (1)
 
Joined: Apr 2008
Posts: 95
Likes: 0
From: Denver/Charlotte
Default

if this works im gonna go and drink myself retarded... ive had a rough time getting my build on the road...and even came as far as selling it. it has alwasy died or stumbled after i give it throttle... i thought o2's but idk. thanks alot bro. i will post soon.
Reply
Old Mar 29, 2009 | 07:40 PM
  #14  
98Camarod's Avatar
11 Second Club
iTrader: (43)
 
Joined: Aug 2006
Posts: 5,364
Likes: 2
From: Summerville, SC
Default

Thats essentially how I have mine setup. You may have to adjust your regulator after you change it.

Don't sell it, you will loose your *** and you know it. Just step back and drink a few and laugh. Builds are fun, and they are projects.
Reply
Old Mar 29, 2009 | 08:47 PM
  #15  
02 BLK WS6's Avatar
10 Second Club
iTrader: (11)
 
Joined: May 2005
Posts: 1,689
Likes: 2
From: Glen Carbon, IL
Default

Originally Posted by camaroIroc
like this?



i guess the only bad thing is i cant really get a stock ls2 rail... it is not a return style

This will allow your pump to run unrestricted and the regulator will control the amount returned to the cell. Idle will create a lot of return and WOT will be less return.
Reply
Old Mar 30, 2009 | 03:02 PM
  #16  
98Camarod's Avatar
11 Second Club
iTrader: (43)
 
Joined: Aug 2006
Posts: 5,364
Likes: 2
From: Summerville, SC
Default

How did that work out?
Reply
Old Apr 3, 2009 | 10:52 PM
  #17  
camaroIroc's Avatar
Thread Starter
Staging Lane
iTrader: (1)
 
Joined: Apr 2008
Posts: 95
Likes: 0
From: Denver/Charlotte
Default

ive got it all hooked up now, and i cranked the car up. my guage is mounted on the front of the fpr, and it now reads 20psi. i tryed adjusting it both ways with the adjustment screw.. but nothing. is this normal in this setup? before it read 60psi at idle. am i doing something wrong?
i'll put a pic up tomorrow....
Reply
Old Apr 4, 2009 | 05:01 AM
  #18  
98Camarod's Avatar
11 Second Club
iTrader: (43)
 
Joined: Aug 2006
Posts: 5,364
Likes: 2
From: Summerville, SC
Default

It's adjustable, so it should be able to go from like 20 psi to 80 psi IIRC. Lets see some pictures, from feed path to the return path.
Reply
Old Apr 4, 2009 | 08:25 AM
  #19  
Old Geezer's Avatar
TECH Senior Member
iTrader: (3)
 
Joined: Jun 2004
Posts: 5,639
Likes: 71
From: GA, USA
Thumbs up Yep...

Originally Posted by 02 BLK WS6
This will allow your pump to run unrestricted and the regulator will control the amount returned to the cell. Idle will create a lot of return and WOT will be less return.
This is the correct way to hook it up...
Is the Walbro in the tank?
The vent valve, if in backwards, will cause the pump to eventually pull a vacuum on the tank, and take the pump out.
The valve is designed to do as you state. Vent when "right side up", close when "on your lid"..
If you are limited to 20psi w/ this layout, I'd look for issues between the rail and the pump pickup.
Reply
Old Apr 4, 2009 | 11:42 AM
  #20  
camaroIroc's Avatar
Thread Starter
Staging Lane
iTrader: (1)
 
Joined: Apr 2008
Posts: 95
Likes: 0
From: Denver/Charlotte
Default

quick question, are walbro pumps loud? mines external. i can hear it, kinda loud.
Reply



All times are GMT -5. The time now is 02:23 AM.

story-0
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

Slideshow: We take a close look at the ONE and Artidiag 800BT2 diagnostic tools from Topdon and the reasons to buy one over the other.

By Pouria Savadkouei | 2026-05-28 11:05:11


VIEW MORE
story-1
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

Slideshow: The controversial Ferrari F6 swaps its original flat-12 for a Corvette Z06-derived LT4 V8 and sends power to four rear wheels through a custom-built drivetrain.

By Verdad Gallardo | 2026-05-26 18:23:54


VIEW MORE
story-2
7 Most Reliable High-Performance Engines GM Has Ever Built

Slideshow:These GM engines didn't just make huge power, they survived abuse, boost, track days, and six-digit mileage with a reputation for refusing to quit.

By Verdad Gallardo | 2026-05-21 16:45:27


VIEW MORE
story-3
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-4
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-5
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-6
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-7
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-8
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-9
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE