94 G50 rear of car hummmmm.......

[chomer]

Symptoms: When the car is idling, there's an "electrical" style humm coming from the back of the car. Audible when I open the trunk. Sounds like it's coming from the area below the rear deck/speakers.

What are the potential causes? How to diagnose?

[q45VIP]

Fuel pump.It'll humm when it starts to go bad.

[AZhitman]

Ah, the dreaded fuel pump....

Have a look about, read up on "fuel pump" in the Q45 forum.

It's not terribly critical, but if left unaddressed, it *can* burn up the Fuel Pump Control unit, which is a bit pricey.

Make sure to keep at least 1/4+ tank of fuel in it at all times, as the pump is cooled by the fuel.

[ceningolmo]

Sounds like the prototype hummm of a failing fuel pump. Check for the article on how to replace it... it's an easy DIY job.

check http://www.q45.org or the NICO articles section for instructions.

[maxnix]

The best link is on this forum where the inestimable Tangalora gives an excellent tutorial.

[chomer]

Thanks guys. Found the article last night after a little searching. As always, it's only *after* I posted that I found it.

Thanks for all the replies. I ordered a bunch of parts from Joe, but left out the controller. He said to check the impedance of the controller before ordering the $500 part, but what is the general concensus? Just replace it (as Q45tech says), or "check"?

$500 goes a long ways...

Oh, and who has info on how to "clean the gas tank"?

[ceningolmo]

I wouldn't replace the controller until it fails. Replace the pump... if the humm goes away, you're fine.