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Fuel Problem


dbarb3
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Had tank off working on electrical issues and replacing fuel pump..  Everything back together now and soon as I turn on key fuel pump initializes and fuel is coming out nipple under tank at high pressure even coming out around clamped tube.  Left nipple as sitting on seat.

Any ideas?

 

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It is being forced out of the nipple opening the one with tube that goes down to injectors.  My understanding was this was an over flow drain but for some reason it is being pressurized

I am baffled

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33 minutes ago, dbarb3 said:

Had tank off working on electrical issues and replacing fuel pump..  Everything back together now and soon as I turn on key fuel pump initializes and fuel is coming out nipple under tank at high pressure even coming out around clamped tube.  Left nipple as sitting on seat.

Any ideas?

 

How much fuel in the tank? Full? sounds like the breather hose is restricted/crimped and return fuel is pressurising the tank.

Ciao

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( A gallon is barely enough to be picked up by the fuel tap on a "Chin-pad", external pump tank. )

As far as your fuel hose routing: Fuel Tap/petcock (left side of the lower tank pannier) --> Fuel pump --> fuel filter --> left injector --> right injector --> regulator (on the right lower pannier) ?

The two "nipples" deep up in the saddle of the tank for venting and overflow should not be connected to any of the fuel supply/return.

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31 minutes ago, dbarb3 said:

It is being forced out of the nipple opening the one with tube that goes down to injectors.  My understanding was this was an over flow drain but for some reason it is being pressurized

I am baffled

I ask about the fuel line routing because I cannot make sense of this "tube that goes down to the injectors" . . .

Maybe an image of that nipple/ tube would help . . .  :pic:

 

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I will take another look tomorrow I know the right nipple is strictly vent

The left one I thought was over flow....  where is it supposed to connect

Its the one fuel is coming out of

 

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So, the under-tank "nipples" (Chin-pad/external pump tank) that exit the bottom of the tank above the spine frame: right is tank vent and left is "overflow"/drain. These should have no connection to the fuel supply/return/ "injectors" . . .

IMG_9503.jpg

IMG_9504.jpg

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Here are my tank connections, as docc said both of the under tank nipples are drains/vents. I have joined the two hoses that connect to these with a garden irrigator 'Y" into a single hose which is routed towards the ground at the left rear of the motor. This was done as my bike was a California spec one which had the tank overflow hose originally plumbed separately to a canister which was removed.

My fuel lines are original so hopefully yours will look the same as mine.

Guzzi left side.JPG

Guzzi right side.JPG

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No wonder I have struggled since day one of getting this bike.  There is no hose attached to the fuel pressure regulator never has been.  The fuel over flow hose from tank was attached to the tee on the right side fuel injection.  The parts diagram isn't much help in figuring this out.

So my guess is there is supposed to be a hose from the back of the tee on the fuel injector to the regulator.

compressjpgFuel 1.jpg

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Yes, once fuel is pumped to the left injector, there is a fuel line connecting to the right injector, and another fuel line from that injector to the inlet of the regulator.

As mentioned, the vent and overflow from the tank nipples hang free.

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The system is basically, fuel pump to left injector to right injector to fuel pressure regulator. The fuel pressure regulator regulates fuel pressure by controlling the flow back into the tank. The more it restricts fuel flow back into the fuel tank the higher fuel pressure is. The less it restricts fuel flow the lower fuel pressure is. The system is pretty much constantly flowing fuel and recirculating it from the pump past the injectors and back into the tank. It is not designed to be a dead head system. It is designed to have a supply and return. The return is at the fuel pressure regulator.

Of note, that exposed nipple on the fuel pressure regulator is just a reference to atmosphere. It is supposed to be empty, to not have a hose on it. It give the fuel pressure regulator a reference to atmospheric pressure.

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