Tired of the Fuel Pump screaming at me....

Over the past six months, the fuel pump has gotten louder in my '79 308. A very annoying high pitched whine that is quite audible from the cabin--even over the engine. After a 3-5 minutes, the pitch note changes to something that is a lot less annoying.

It's the original pump--and from both my mechanic and all you wonderful fchat folks, it sounds like this is a common failure point.

So I replaced it this week with a new Hardi 18812 pump.

Also the PO had gotten rid of the 3-way valve that enables a bypass in the event of a severed line and replaced with a straight 3-way hose fitting. In other words, the pump was not only pressurizing the carb feed lines, but also bypassing back to the input of the pump (yes, this is a bad setup). I'd thought that change of pitch might've been the pump struggling to build pressure b/c of that bypass and then finally being successful as the system reached an equilibrium.

So, before replacing, I also took the opportunity to record the pump sound both with and without the bypass (using a hose clamp). Turns out it didn't make a difference--that pump was just loud and as it warmed up, it simply changed it's note.

So after replacing the pump AND removing the bypass entirely (set up like the EU-spec cars), it's so so much better. I can still hear the pump lightly before the engine is started, and then nevermore.

Will post a couple videos of the before and after.

 

Arg...video files are too large to post. Lemme put 'em onto a share drive somewhere...

 

Cut the video's down. Here's the first one (original pump)

 

And the second one (Hardi pump).

 

The new fuse block should almost certainly providing better voltage to the pump than the stock block, so it's not surprising that the "note" of the pump might change. Usually, I'd expect a higher pitch (more voltage = higher motor speed) -- but quieter? That is unexpected.

I assume it's still working and you didn't just forget to connect the wire for the fuel pump If that were the case, then a quieter pump would be expected....

 

They don't. You'll note in John's photo that the covers are shorter than the fuse block (one side bisects the outer fuse) and that they aren't seated onto the block itself. I'm guessing John's done some creative work to get them to stay in place...