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09-06-2021, 02:38 PM
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#1 |
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Registered User
Join Date: Sep 2009
Location: east tennessee
Posts: 158
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Need help with fuel pressure
53 3100 5.3 0ut of 2003 avalanche. 50 lbs fuel pressure with 3 diffrent fpr. get lean codes lt fuel trims stay maxed out 25%. Last fpr today 5olbs goes to 40s with more throttle unhook vacuum line goes to 58 lbs .Will it hurt to plug vacuum line and run it?????
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09-06-2021, 06:44 PM
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#2 |
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Post Whore
  
Join Date: May 2015
Location: Alabama
Posts: 14,671
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Re: Need help with fuel pressure
You gonna need more than 50psi...how do you have your fpr plumbed?
I'm assuming you have a inline pump and reg.. Or are you using a return rail?
__________________
Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver |
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09-06-2021, 07:22 PM
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#3 |
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Registered User
Join Date: Sep 2009
Location: east tennessee
Posts: 158
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Re: Need help with fuel pressure
return rail new fuel lines pump and same part number filter for the avalanche
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09-06-2021, 07:38 PM
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#4 |
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Post Whore
Join Date: May 2015
Location: Alabama
Posts: 14,671
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Re: Need help with fuel pressure
I'm not sure on that..
Eric (ls1nova) would probably know for sure
__________________
Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver |
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09-09-2021, 07:17 PM
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#5 | |
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BMW & ASE Master Certified
Join Date: Feb 2004
Location: Houston, Texas
Posts: 1,266
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Re: Need help with fuel pressure
Quote:
lean can also be air leaks. need to smoke test the intake to find whats leaking if anything is. intake can be cracked, vacuum port left unplugged pinched intake gaskets... smoke test will find the leaks
__________________
1987 Silverado - L83 5.3 w/ 6L80e ,A/C,P/W,P/L,TILT, HID projectors, Wilwood C-10 Pro Spindles w/ 2018 silverado front brakes & C-5 Corvette Rear Disc Brakes 1999 BMW 528i - 5.7 LS1 w/ 4l60e, Ford 8.8 IRS w31 spline posi & FX-r projector retrofit New project: 2006 BMW x5 6cyl AWD to L83 6l80e 4wd to 2WD / RWD A poor man buy's it twice finally got my domain name back, 87chevy.com.... site rework in progress |
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09-17-2021, 10:07 PM
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#6 |
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Senior Member
 
Join Date: Sep 2005
Location: Lewisville, Nc
Posts: 10,237
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Re: Need help with fuel pressure
What pump are you running intank or inline what model? Return style system with for 9n fuel rial?
__________________
David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube |
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09-19-2021, 09:31 AM
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#7 |
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Registered User
Join Date: Sep 2009
Location: east tennessee
Posts: 158
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Re: Need help with fuel pressure
New factory part number pump for 2003 avalanche second one. factory inline filter. return style on 03 avalanche. 3 different fpr all show 50lbs pressure. get lean codes for both sides every 5 or 6 hundred miles. put 4000 miles on it so far. unhook fuel pressure goes to 58lbs and stays. runs ok with fpr hooked up will backfire one time when you run it wfo then let off. whole fuel system is same as factory with new 3/8 fuel line. bought whole avalanche had been flipped but I drove it into garage dont know much else to tell
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09-19-2021, 12:14 PM
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#8 |
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Registered User
Join Date: Dec 2009
Location: Independence Mo
Posts: 4,119
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Re: Need help with fuel pressure
Post a pic of the fuel rail, injectors and fuel pressure regulator.
__________________
My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html 5.3 swap into my RUSTY '71 C10 http://ls1tech.com/forums/conversion...71-c-10-a.html |
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09-19-2021, 12:20 PM
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#9 |
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Registered User
Join Date: Sep 2009
Location: east tennessee
Posts: 158
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Re: Need help with fuel pressure
70 years old will have to find someone else do do pic it is not flex fuel and no vacuum leaks
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