Fuel pump noise

[Sublime]

Or should I say noise at the fuel pump? So my 78 k10 350 developed a ticking/knocking noise. The noise is only heard below 1000 rpm and after the engine is at operating temp. Engine oil pressure is at 30psi at idle and 70psi at 2500 rpm when warm. So I am pretty sure its not a rod or main bearing. Started diagnosing by removing one plug wire at a time while the engine was running, the noise did not go away, I then removed both valve covers and checked lifter adjustment, noise was still there. I cannot tell where the noise is, it seams to be louder when I crawl underneath. A friend of mine lent me his stethoscope. I listened to the valve covers, intake manifold, header tubes one by one, transmission, oil pan, flex dust cover water pump, ps pump and finally the mechanical fuel pump. No doubt the noise is either the fuel pump OR something very close to the fuel pump.
Has anyone ever experienced this? The pump is obviously working and not leaking.
Thanks in advance

 

[Rusty Nail]

They're pretty cheap. I'd have changed it by now.

 

[Sublime]

They're pretty cheap. I'd have changed it by now.

Come on over and geter done !

 

[Rusty Nail]

Ah!
I would dude but I gotta go to work...

 

[Sublime]

LOL, ya that 4 letter word! work.

 

[Rusty Nail]

Meh.
It's been days, did you get it changed yet?

Post pics.

 

[Sublime]

Sublime

Not my daily driver so I plan on doing it this weekend.

 

[Sublime]

update - so I changed the fuel pump today, twice LOL. The new pump leaked at the crimped seal - ahh - so back to the parts store for an exchange. This one differed because its pump arm spring was exposed. The one I took off and the new one that leaked did not have the exposed spring.
The noisy pump had a lot of play in the arm that was causing the noise.
Bottom line if you develop an engine noise that sounds somewhat like a lifter noise be sure to check the fuel pump.

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[1987 GMC Jimmy]

Is that a Delphi pump? That weirded me out when I bought one a while back.

 

[Sublime]

Is that a Delphi pump? That weirded me out when I bought one a while back.

I do not know, I did not see any markings on the pumps.

 

[Rusty Nail]

Wild.
How long you reckon that pump was in service? That looks like significant wear to me.

 

[Sublime]

The engine was rebuilt in 2012. The truck sat a lot so not too many miles on it. I wonder if the wear came from the fuel push rod slamming the rod because of the broken spring.

 

[Rusty Nail]

Ya, probably.