Should both fuel pumps hum when started?? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

92470 · 08-23-2009, 10:28 PM

I have a 87' V10 with dual tanks. I also have the very common problem of only one tank working. I am trying to isolate what the problem is, and I have determined it is not the in dash switch or the frame mounted selector valve. I know that both tanks have a fuel pump in them and what I was wondering was when I turn the ignition key, I can hear the drivers side pump hum (the side that works). The passenger side doesn't. Should they both "hum" when the key is turned on? I'm sure I will be dropping the tank and replacing the pump or sending unit (while I'm at it both), but if I knew the pump was supposed to hum and wasn't, I would feel better about diving in. Any advice is apprciated. Thanks

BLE 'BURBAN · 08-24-2009, 01:07 AM

Only the selected tanks pump should be heard when you first turn on the key. the pumps are wired throught the switching valve along with the sender unit.

92470 · 08-24-2009, 09:10 AM

Thanks for the response. That's what came to mind after I posted the question, but haven't checked it yet.

So if I switch my tank to the one that currently doesn't work, then turn on the key, if the fuel pump on that side is working, I should here it hum? I'll have to try this tonight.

08-23-2009, 10:28 PM	#1
92470 Registered User Join Date: Nov 2006 Location: Maple Grove, MN Posts: 149	Should both fuel pumps hum when started?? I have a 87' V10 with dual tanks. I also have the very common problem of only one tank working. I am trying to isolate what the problem is, and I have determined it is not the in dash switch or the frame mounted selector valve. I know that both tanks have a fuel pump in them and what I was wondering was when I turn the ignition key, I can hear the drivers side pump hum (the side that works). The passenger side doesn't. Should they both "hum" when the key is turned on? I'm sure I will be dropping the tank and replacing the pump or sending unit (while I'm at it both), but if I knew the pump was supposed to hum and wasn't, I would feel better about diving in. Any advice is apprciated. Thanks

08-24-2009, 01:07 AM	#2
BLE 'BURBAN In the Forgotten far North. Join Date: Jul 2007 Location: Anchorage, Alaska Posts: 2,627	Re: Should both fuel pumps hum when started?? Only the selected tanks pump should be heard when you first turn on the key. the pumps are wired throught the switching valve along with the sender unit. __________________ 1987 R3500 CREW CAB DUALLY (BIG RED)Acquired 06/12/2015 1990 chevy suburban V2500 5.7L My cluster Mods-Nov 2007 overhead console Stereo install Round 2 Aug 2009 Heated/turn signal mirror upgrade

08-24-2009, 09:10 AM	#3
92470 Registered User Join Date: Nov 2006 Location: Maple Grove, MN Posts: 149	Re: Should both fuel pumps hum when started?? Thanks for the response. That's what came to mind after I posted the question, but haven't checked it yet. So if I switch my tank to the one that currently doesn't work, then turn on the key, if the fuel pump on that side is working, I should here it hum? I'll have to try this tonight.



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