[Crumpler]

Hey guys, I'm looking for opinions with this one.
After an extended dyno session, warm day, my fuel pump was making more noise. I would state same type of noise, but louder.
Performance was unchanged, but obviously I need to chase this.
I will look at usual suspects, but it occurred to me that I read about fuel pumps making more noise with hot fuel. Can this be true? Cavitation? Pre-vapor lock?
The tank was 3/4 full, so level was not low at all.

The stock fuel cooler is essentially inert since I have deleted the a/c.
This is another angle I did not appreciate ahead of time.
Running a stock fuel pump, based on mathematics with the low boost SC, I didn't see the need to upgrade to a Bosch 044 pump, but i could certainly add an inline cooler without a lot of effort.
Thanks.

[worf]

My opinion…meh.

Vapor lock is caused by high-pressure fuel vapor displacing fuel in the fuel rails back to the fuel pump which then can’t generate fluid pressure due to fast system pressure drop after shutting off the engine.

In a running engine vapor lock can’t really happen and cavitation shouldn’t be an issue provided you’re using ‘good’ summer gasoline that has anti-foaming agents as part of the additive package.

Now, if perhaps, it is hot, the tank is 1/8 full and you’re on a dyno then maybe you’ll get some foamy gas.

Alternatively… when was the last time you look at the tank strainer? Or at how much sediment was at the bottom of the tank? Fuel filter age?

I’d chase the obvious first…

[Crumpler]

Ok.
Deeper dive.
With sender out, the strainer looks reasonable but I’m going to replace it while I’m in there.
Thoughts on diaphragm? I assume it’s to stabilize sender. Looks like I tore it removing sender, assuming not a big deal.

[Crumpler]

Ok now I’m finding threads about this obscure swirl pot.
What’s my move?

[Crumpler]

[worf]

Ok now I’m finding threads about this obscure swirl pot.
What’s my move?

You pulled the strainer and it appears to be in good shape. I can’t tell if the bowl is clean of debris.

[Crumpler]

Thanks for following Dave.
It’s all good except for this crack/tear on the lid of this swirl pot thing. If lid secure on pot am I good to go?

[worf]

If lid secure on pot am I good to go?

Yes.

Change your fuel filter if it’s old-ish.

Reverse polarity your fuel pump and back-flush any crap.

Check your lines from filter to engine bay for damage/crushed/pinched spots.

[Crumpler]

Thanks man!

[Crumpler]

Side note.
Replacing fuel line from filter to hard line in rear fender.
Never heard of one failing. I assume because no real heat cycles like in engine, but it’s pressured and 37 years old right?

[worf]

Never heard of one failing. I assume because no real heat cycles like in engine, but it’s pressured and 37 years old right?

That’s pretty much my logic at this point: 28 to 46 years old. So, if I’m “there” it goes.

[Crumpler]

Um, I don’t plan on being up side down, but what about this check valve coming off the linear expansion tank? Anti-roll valve some one said once.
Replace? I would expect any check valve to be shot by now, pessimistic?

[worf]

Um, I don’t plan on being up side down, but what about this check valve coming off the linear expansion tank? Anti-roll valve some one said once.
Replace? I would expect any check valve to be shot by now, pessimistic?

Should be easy enough to test. IIRC, it’s a stainless ball bearing in a sleeve. Russian engineering not German engineering. (i.e. doesn’t work very well, but is hard to kill.)

[Crumpler]

[Crumpler]

New fuel pump, filter, strainer, sender, fuel line, and r/r cradle. Going jump fp relay in the am and confirm no leaks and normal pressure on the rail.