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?????

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?

Re: Need help with fuel pressure
 

return rail new fuel lines pump and same part number filter for the avalanche

Re: Need help with fuel pressure
 

I'm not sure on that..
Eric (ls1nova) would probably know for sure

Re: Need help with fuel pressure
 

Post a picture of the fuel rail. maybe a bad regulator. what fuel pump. maybe poor quality parts causing fuel pressure problem?

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

Re: Need help with fuel pressure
 

What pump are you running intank or inline what model? Return style system with for 9n fuel rial?

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

Re: Need help with fuel pressure
 

Post a pic of the fuel rail, injectors and fuel pressure regulator.

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