[Geej]

I'll try to keep this short. I've done a lot of searching and testing and I think I've got things roughly figured out but wanted to verify.
2004 Touareg V8
Starts, runs for 30-40 seconds and then dies. Pump behind the DRIVERS seat runs to prime and for 30 ish seconds after car starts, after it shuts down, the car dies shortly thereafter. 183k and pumps have never been touched. Opened up access and ran tests pulling plugs on the access holes (on the fuel tank under the rear seat) and alternately the 404 relays...the pump behind the passenger seat on the RIGHT side will not run from our tests. So I feel I determined I need a right side pump.
My question is this: if I pull the C20 404 relay, it will keep the left side pump running and the car will run fine indefinitely. (I know some cars that relay is in position C19, but on mine it's C20. Position A6 appears to control the left hand pump that is behind the drivers seat and C20 either directly controls the right hand pump behind the pax seat or it controls the switching between pumps). I of course have checked fuses.
While I get a new pump ordered and find time to replace, is there any reason I can't drive with just that one pump?
Any other thoughts you have, please let me know.
Thanks!

 

[schrickman]

Fly at your own risk... but at least it starts and goes.

 

[G6mdxvct]

I'll try to keep this short. I've done a lot of searching and testing and I think I've got things roughly figured out but wanted to verify.
2004 Touareg V8
Starts, runs for 30-40 seconds and then dies. Pump behind the DRIVERS seat runs to prime and for 30 ish seconds after car starts, after it shuts down, the car dies shortly thereafter. 183k and pumps have never been touched. Opened up access and ran tests pulling plugs on the access holes (on the fuel tank under the rear seat) and alternately the 404 relays...the pump behind the passenger seat on the RIGHT side will not run from our tests. So I feel I determined I need a right side pump.
My question is this: if I pull the C20 404 relay, it will keep the left side pump running and the car will run fine indefinitely. (I know some cars that relay is in position C19, but on mine it's C20. Position A6 appears to control the left hand pump that is behind the drivers seat and C20 either directly controls the right hand pump behind the pax seat or it controls the switching between pumps). I of course have checked fuses.
While I get a new pump ordered and find time to replace, is there any reason I can't drive with just that one pump?
Any other thoughts you have, please let me know.
Thanks!

Just remember there are two sides of the fuel tank. The primary and larger capacity is behind the drivers seat the secondary chamber behind the pax is smaller. If you just run off the primary/ priming/transfer pump fuel on the pax side will not be used. The pump behind drivers transfers fuel to the pax side as needed. Not certain the capacity difference between two sides but would not let fuel level drop to less than half a tank.

 

[williewill]

I'll try to keep this short. I've done a lot of searching and testing and I think I've got things roughly figured out but wanted to verify.
2004 Touareg V8
Starts, runs for 30-40 seconds and then dies. Pump behind the DRIVERS seat runs to prime and for 30 ish seconds after car starts, after it shuts down, the car dies shortly thereafter. 183k and pumps have never been touched. Opened up access and ran tests pulling plugs on the access holes (on the fuel tank under the rear seat) and alternately the 404 relays...the pump behind the passenger seat on the RIGHT side will not run from our tests. So I feel I determined I need a right side pump.
My question is this: if I pull the C20 404 relay, it will keep the left side pump running and the car will run fine indefinitely. (I know some cars that relay is in position C19, but on mine it's C20. Position A6 appears to control the left hand pump that is behind the drivers seat and C20 either directly controls the right hand pump behind the pax seat or it controls the switching between pumps). I of course have checked fuses.
While I get a new pump ordered and find time to replace, is there any reason I can't drive with just that one pump?
Any other thoughts you have, please let me know.
Thanks!

The problem may be the jet pump or a leaking hose in the tank. The right side of the tank may be running out of gas while all the fuel is on the left side causing the gauge to act properly

 

[G6mdxvct]

The problem may be the jet pump or a leaking hose in the tank. The right side of the tank may be running out of gas while all the fuel is on the left side causing the gauge to act properly
[/QUOTE
The internal hoses and connectors are fairly robust. It is possible that a push pull connector is loose and worth checking the lines that go to the other side of the tank. The fuel gage relies on float type sensors that are in both sides of the tank. Both have to work properly to get correct fuel gage reading. My bet is the primary pump can provide enough low pressure fuel to the high pressure pump on injector rail, but not generate enough pressure to transfer fuel to the secondary side of tank. My bet the priming & transfer pump is toast.