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Mark Ugrich · 05-05-2014, 07:13 PM

I'm hoping somebody here might have some ideas. On my 1984 GMC 454 3/4 ton 2WD Suburban I hear a knocking/banging noise on the center right side of the body.After checking I found the fuel line knocks in cadence with rpm and fuel pump.You can actually feel the line pulse if you hold it.I've replaced the fuel sending unit and sock all the rubber fuel lines,fuel pump with an AC Delco unit,blown out the lines with compressed air and replaced the line from the pump to the carb with braided line.Replaced the gas cap too.I'm thinking air must be entering either the main fuel line or the return line,but I don't see how.The knocking isn't there all the time it comes and goes.Has anybody seen this before?It's drivin' me nuts.Turning up the radio does help

Thanks in advance, Mark

05-05-2014, 07:13 PM	#1
Mark Ugrich Member Join Date: May 2011 Location: Auburndale,Florida Posts: 201 Likes: 20 Liked 57 Times in 32 Posts	hydrauliced fuel line I'm hoping somebody here might have some ideas. On my 1984 GMC 454 3/4 ton 2WD Suburban I hear a knocking/banging noise on the center right side of the body.After checking I found the fuel line knocks in cadence with rpm and fuel pump.You can actually feel the line pulse if you hold it.I've replaced the fuel sending unit and sock all the rubber fuel lines,fuel pump with an AC Delco unit,blown out the lines with compressed air and replaced the line from the pump to the carb with braided line.Replaced the gas cap too.I'm thinking air must be entering either the main fuel line or the return line,but I don't see how.The knocking isn't there all the time it comes and goes.Has anybody seen this before?It's drivin' me nuts.Turning up the radio does help Thanks in advance, Mark