Dual fuel tank help please - The 1947 - Present Chevrolet & GMC Truck Message Board Network

rwolf9653 · 09-23-2012, 08:07 PM

My grandfather has a 1987 V10 with the 305 and it cut out on him the other day. Now it will turn over, but not start. I spent a little time looking at it today and it is not getting fuel to the throttle body. I can hear a fuel pump run when it is on LEFT tank, but no pump noise when on RIGHT tank. I pulled the fuel filter and turned the key to the "ON" position and heard the pump run but no fuel came from the lines (left tank only, I tried right but no pump noise). I have not worked on the dual tank setup at all so can anyone explain this to me please?

Is there only one pump, or two?
There is only one fuel filter so I am assuming one tank pumps into the other? Left to right maybe?
It looks like the right tank is the main tank that feeds the throttle body, so if that pump quits there will be no fuel regardless of the LEFT pump working?

Any info is much appreciated. I hope to get the parts and make another trip down there to fix it, but he is two hours away so I would like to have what I need before I go.

**hatzie** · 09-23-2012, 10:19 PM

Quote:

Originally Posted by rwolf9653

My grandfather has a 1987 V10 with the 305 and it cut out on him the other day. Now it will turn over, but not start. I spent a little time looking at it today and it is not getting fuel to the throttle body. I can hear a fuel pump run when it is on LEFT tank, but no pump noise when on RIGHT tank. I pulled the fuel filter and turned the key to the "ON" position and heard the pump run but no fuel came from the lines (left tank only, I tried right but no pump noise). I have not worked on the dual tank setup at all so can anyone explain this to me please?

Quote:

Originally Posted by rwolf9653

Is there only one pump, or two?

One fuel pump in each tank... 2 fuel pumps.

Quote:

Originally Posted by rwolf9653

There is only one fuel filter so I am assuming one tank pumps into the other? Left to right maybe?

Not in stock dress. The selector valve switches the feed and return lines from Left or Right tanks to the engine compartment fuel feed and returns. The fuel filter is after the valve.

Quote:

Originally Posted by rwolf9653

It looks like the right tank is the main tank that feeds the throttle body, so if that pump quits there will be no fuel regardless of the LEFT pump working?

No.

It sounds like the selector has moved to the RIGHT tank then hung... And... the RIGHT tank has a fuel pump issue.

superwade57 · 09-23-2012, 10:26 PM

I'd unplug the selector switch and try jumping it. Odds are good in my experience that the selector switch went bad. I've had three go bad on me in the last two years. Three dif trucks. All of them sat for a couple years then woulndt start. That 12$ switch was the culprit on my 80,86 and 87. You can diagnose but operating the switch with key on truck off you should be able to hear the selector move its kind of a hollow clunking noise. For lack of a better term
Posted via Mobile Device

rwolf9653 · 09-24-2012, 08:58 PM

Thanks for all the help. I will go down there this weekend with a selector and a pump and I feel confident we can get it going. Thanks again.

09-23-2012, 08:07 PM	#1
rwolf9653 more ideas than money Join Date: Dec 2008 Location: spring grove, pa Posts: 1,068	Dual fuel tank help please My grandfather has a 1987 V10 with the 305 and it cut out on him the other day. Now it will turn over, but not start. I spent a little time looking at it today and it is not getting fuel to the throttle body. I can hear a fuel pump run when it is on LEFT tank, but no pump noise when on RIGHT tank. I pulled the fuel filter and turned the key to the "ON" position and heard the pump run but no fuel came from the lines (left tank only, I tried right but no pump noise). I have not worked on the dual tank setup at all so can anyone explain this to me please? Is there only one pump, or two? There is only one fuel filter so I am assuming one tank pumps into the other? Left to right maybe? It looks like the right tank is the main tank that feeds the throttle body, so if that pump quits there will be no fuel regardless of the LEFT pump working? Any info is much appreciated. I hope to get the parts and make another trip down there to fix it, but he is two hours away so I would like to have what I need before I go. __________________ Randy 1948 Chevy 3100 5 window 1966 Chevy C30 Dually 1967 Chevy K10 1972 Chevy K20 1972 Chevy C10 1972 Chevy K5 Blazer 1987 Chevy V10 2003 Chevy Suburban

09-23-2012, 10:26 PM	#3
superwade57 Registered User Join Date: Jul 2010 Location: Janesville, WI Posts: 664	Re: Dual fuel tank help please I'd unplug the selector switch and try jumping it. Odds are good in my experience that the selector switch went bad. I've had three go bad on me in the last two years. Three dif trucks. All of them sat for a couple years then woulndt start. That 12$ switch was the culprit on my 80,86 and 87. You can diagnose but operating the switch with key on truck off you should be able to hear the selector move its kind of a hollow clunking noise. For lack of a better term Posted via Mobile Device

09-24-2012, 08:58 PM	#4
rwolf9653 more ideas than money Join Date: Dec 2008 Location: spring grove, pa Posts: 1,068	Re: Dual fuel tank help please Thanks for all the help. I will go down there this weekend with a selector and a pump and I feel confident we can get it going. Thanks again. __________________ Randy 1948 Chevy 3100 5 window 1966 Chevy C30 Dually 1967 Chevy K10 1972 Chevy K20 1972 Chevy C10 1972 Chevy K5 Blazer 1987 Chevy V10 2003 Chevy Suburban



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