The fuel pump has been making the regular 'whir' sound but just today changed to a 'hiss' sound (no leaks). Still seems to work fine. I will replace but do these normally die right away once the 'whir' turns to a 'hiss'? I'd like to finish the season without having to wait for the part. Should I take my chances?

Also does this normally mean there is sediment in the gas tank that has clogged the pump? The pump doesn't look very old. I think I remember the PO said he replaced it in the past few years.

Depends on the pump. Some of the cheapie pumps will clog an burn up. Some you can disassemble and clean, others not. Gotta have clean fuel running into those babies

Hopefully not to derail this thread, but I've noticed a fairly loud 'whir' sound while driving. Seems to increase in noise level with speed, and gets quieter when slowing down. I was thinking along the lines of differential noise, but is it common for the fuel pump to make a loud whir?

seabeelt wrote:Depends on the pump. Some of the cheapie pumps will clog an burn up. Some you can disassemble and clean, others not. Gotta have clean fuel running into those babies

K. Thanks. I was planning on taking it off and see what I can see.

Richard

Went under the car, ensured connections were tight (they were) and checked for noise more closely. Turns out the inlet for the pump wasn't seated in the shield before. Seating it correctly in the shield changes the sound from the whir to a bit more of a hiss sound. I moved it up, changed to a whir, moved in down, changed to more of a hiss, etc... I think the sound just travels a bit more to the car body and the sound changes.

There are no leaks anywhere and the hoses are fine. So I think this is a non-issue.

I didn't notice before but the fuel vapor check valve connection came off. Could this have caused the hissing noise when the fuel pump was running? I'm thinking the hose that came off goes to the charcoal canister and the suction from the engine caused the hissing noise.

And if the check valve was clogged would it cause vapor pressure in the gas tank so when I open the gas filler cap I hear an air suction sound? Here's a few pictures before I cleaned it.







Looks clogged to me. Initially I wasn't able to blow through the valve. After cleaning out some of the junk I can blow in both sides and air goes through... slowly but it goes through. Looks like a 2-way valve to me (ie. I can get air to flow through blowing in either side). So it's not directional, correct?

After cleaning 2-way valve, reattached with proper clamps and everything runs great. No hiss anymore and much smoother.

Good stuff! But you really need one of these guys between your fuel tank and pump:

KevAndAndi wrote:Good stuff! But you really need one of these guys between your fuel tank and pump:

Is that a fuel return check valve? If so I have an '81 FI so I don't think I have one of those according to the description on the AR site.

http://www.autoricambi.us/product/FU0-0 ... eck-Valve/

I was going to ensure this thing isn't clogged as well.

http://www.autoricambi.us/product/FU0-0 ... por-Union/

I haven't looked closely but I think this is the unit in the trunk on the driver's side. Can I just remove all the connections (note which ones go where) and clean with carb cleaner and ensure it's not clogged?