Broken piece on fuel pump assembly
Melting Slicks
Joined: Aug 2004
Posts: 2,924
Likes: 229
From: Oakbank Manitoba
A certain minimum amount of fuel pressure is needed in the drivers side fuel module for the fuel transfer function to operate correctly from one tank to the next. If the modified engine demands more fuel than the stock pump can deliver than the fuel pressure will drop below this mimimum amount and fuel will no longer be transferred from one tank to the other.
Melting Slicks
Joined: Aug 2004
Posts: 2,924
Likes: 229
From: Oakbank Manitoba
According to your pictures it uses a metered orifice to create the suction needed to draw in fuel from the bottom of the tank. In the factory shop manual it's listed as a venturi pump.
Last edited by KENS80V; Mar 8, 2017 at 01:28 PM.
Thread Starter
Racer
Joined: Apr 2015
Posts: 278
Likes: 6
A certain minimum amount of fuel pressure is needed in the drivers side fuel module for the fuel transfer function to operate correctly from one tank to the next. If the modified engine demands more fuel than the stock pump can deliver than the fuel pressure will drop below this mimimum amount and fuel will no longer be transferred from one tank to the other.
oh oh okay that makes sense, so while I'm WOT there is no fuel transfer from the passenger side. The fuel pressure created by the "aux" line is what helps start the process. So in the end it's best to just use it as factory without drilling holes in the bucket. The holes in the bucket would cause a pressure differentiation that that of oem. I plan on selling the car within the year and don't want to screw anyone over. So I guess I'll just wait on the new assembly.
Melting Slicks
Joined: Aug 2004
Posts: 2,924
Likes: 229
From: Oakbank Manitoba
The boost a pump feature is used to increase the fuel pump speed to help the pump keep up with the fuel needs at WOT. There will be a certain horsepower level where even the boost a pump can't keep up. Then people resort to custom fuel assemblies with twin pumps or even triple pumps. This really screws with the fuel transfer function. There are different methods to help sort things out including drilling holes in the factory plastic tanks to add certain lines.
Thread Starter
Racer
Joined: Apr 2015
Posts: 278
Likes: 6
The boost a pump feature is used to increase the fuel pump speed to help the pump keep up with the fuel needs at WOT. There will be a certain horsepower level where even the boost a pump can't keep up. Then people resort to custom fuel assemblies with twin pumps or even triple pumps. This really screws with the fuel transfer function. There are different methods to help sort things out including drilling holes in the factory plastic tanks to add certain lines.
Melting Slicks
Joined: Aug 2004
Posts: 2,924
Likes: 229
From: Oakbank Manitoba
oh oh okay that makes sense, so while I'm WOT there is no fuel transfer from the passenger side. The fuel pressure created by the "aux" line is what helps start the process. So in the end it's best to just use it as factory without drilling holes in the bucket. The holes in the bucket would cause a pressure differentiation that that of oem. I plan on selling the car within the year and don't want to screw anyone over. So I guess I'll just wait on the new assembly.
Install the new broken modules pump in the original module and then sell it.
Thread Starter
Racer
Joined: Apr 2015
Posts: 278
Likes: 6
Just wanted to clarify some information in case someone else comes across this. The small line that runs from the fuel pump to the bottom of the bucket is there to in fact aid in keeping the bucket full. The transfer from the passenger side tank is not affected whether or not the line is used. Ill post the picture/diagram of an old photo that I had saved on my computer and totally forgotten about. The main feed line has an "aux" line which goes to the passenger side tank and creates the fuel transfer via the jet pump.
