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Old 03-15-2007, 04:56 PM   #1
dave2953
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Fuel Pump Knock

My 68 has had a fuel pump noise ever since I swapped my 307 for an '86
305. I used the fuel pump and shaft from the 307 and it made knocking noises under load at slow speed. I got a new pump, but the noise remains. Any ideas??
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Old 03-15-2007, 07:41 PM   #2
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Re: Fuel Pump Knock

Fuel pump cam lobe worn?
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Old 03-15-2007, 07:54 PM   #3
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Re: Fuel Pump Knock

I don't think so. I haven't actually inspected the cam, but neither end of the pump shaft has irregular wear. Could that lobe be worn without the shaft showing any signs?
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Old 03-15-2007, 10:00 PM   #4
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Re: Fuel Pump Knock

Iwould think there would be some sign of wear. Are you 100% sure the pump is the source of the noise. A little trick is a long card board tube like from gift wrap kinda make an impromto mechanic stethescope. RJ22
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Old 03-16-2007, 05:20 AM   #5
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Re: Fuel Pump Knock

I use a piece of long heater hose as a "stethoscope". You can heaer the noise coming directly from the pump housing. I chased this noise everywhere before I could finally isolate it.
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Old 03-16-2007, 07:38 AM   #6
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Re: Fuel Pump Knock

I suggest you changeout the fuel pump. Those things are known to make a knocking noise when the rocker gets worn in the pivot point. It will sound like a rod knock, soon.
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Old 03-16-2007, 11:59 AM   #7
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Re: Fuel Pump Knock

I replaced it about 2 weeks ago, but no change. I thought trying an '86 pump, but it has the provision for the return. Can I still use it if I cap the return?
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Old 03-16-2007, 12:30 PM   #8
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Re: Fuel Pump Knock

YES, you can cap the return.
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Old 03-16-2007, 12:36 PM   #9
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Re: Fuel Pump Knock

I may try that and see if my noise goes away. Thanks for help.
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Old 07-30-2007, 11:08 AM   #10
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Re: Fuel Pump Knock

Dave:
Did you ever solve your fuel pump knock? My broomstick tells me that is where my knock is located.

I found my all my other knocks- I learned that big cams and stock valve covers do not play well together.
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