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1976 Fleetwood Fuel Pump

Started by Frank Palacio, May 29, 2014, 05:23:19 PM

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Frank Palacio

Hello
Just wondering if anyone might know the answer here.  I have a 1976 Fleetwood with 64K original on it.  I noticed that after running for awhile, I would turn her off, and then when I went to restart, she would have a hard time.  Meanwhile, I could hear the fuel pump on the chassis under the door buzzing.  I bought a new fuel pump.  Had it installed.  She starts right up now, but, this pump seems to buzz the same as the previous, maybe even louder.  Any thoughts?
Frank

TJ Hopland

I assume this is an EFI car?  I didn't think there was a fuel pump under the door.  I thought one was in the tank and the other was fairly close to the tank but I suppose that could be fairly close to the door.    I also didn't think they ever shut off.   I wonder if the fuel pump relay part of your ECU is on its way out?   It was apparently a common failure point.   
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Frank Palacio

Yes, there is one other than in the tank.  I guess it's fairly close to the tank.  It's under the back door on the driver side.  I'm not sure about the fuel pump relay part you are referring to?  Where is that located?
Frank

Dave Shepherd

That buzzing my not be an issue, they were not well insulated from the chassis as they were mounted.

Gene Beaird

If the lift pump, back at the gas tank fails, it will cause the pump on the frame to be louder.  It's a sure sign that the lift pump is failed, so I'd inspect/replace that pump, too. 

Gene Beaird,
1968 Calais
1979 Seville
Pearland, Texas
CLC Member No. 29873

Frank Palacio

Purchased the lift pump.  Having it installed today, so.....hopefully that solves the problem.  The pump on the frame is extremely loud, more so than it should be.  If I'm at a traffic light stopped with the window down, it is very noisy.
Frank

Gene Beaird

Yep, sounds like a dead lift pump.  I know others have wrapped their external pump in some rubber sheeting then put it in the mount and that has made the pump even quieter. 
Gene Beaird,
1968 Calais
1979 Seville
Pearland, Texas
CLC Member No. 29873

bcroe

Quote from: Frank PalacioPurchased the lift pump.  Having it installed today, so.....hopefully that solves the problem.  The pump on the frame is extremely loud, more so than it should be.  If I'm at a traffic light stopped with the window down, it is very noisy.  Frank 

Is it a fuel injected car?  If so,  this is a good time to add a fuel pump relay to the Engine
Control Unit, before the ECU gets burned out. 

What the EFI cars really need, is a high pressure in tank pump, so all that stuff on
the frame goes away, including the noise.  Maybe a newer model has a suitable gas
pickup unit.  Bruce Roe

Glen

I have minimal experience with electric fuel pumps but with what I have so far I find that when the electric pump gets loud it is usually because it is running dry.  When actually pumping fuel it is much quieter. 

Just something to think about. 


Glen Houlton CLC #727 
CLCMRC benefactor #104

TJ Hopland

Quote from: Frank Palacio on May 29, 2014, 07:24:25 PM
I'm not sure about the fuel pump relay part you are referring to?  Where is that located?

I have not seen it myself but Bruce has described it many times.   Apparently the relay for the fuel pump(s) is on the main circuit board on the ECU.  Apparently especially when the pumps get old and begin to fail they draw too much power and damage the connectors and circuit board.   I believe Bruce is usually able to repair them but even after the repair its best to install an external relay so it can't happen again.   Basically there is a terminal that sends out +12V when the fuel pumps are supposed to be running and originally ran direct to the pumps.   For the modification you install a modern heavy duty external relay so that 12v signal from the ECU now just powers the new relay instead of the full load of both pumps.   That way if the pump circuit becomes overloaded you just blow a fuse or possibly damage a $5 relay you can get at any parts store rather than a very old ECU full of obsolete parts that only a few people in the world will even attempt to work on.    From what I have read the 500 ECU's are very rare since they were only an option for late 75 and 76. 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason