Join Date: Mar 2008
Location: New England '13 XTS Platinum
A Tech 2 is an indispensable scan tool to diagnose fuel delivery problems with the XLR. Unless you have one, you'll need to visit your local Cadillac dealer.
The twin-tank fuel delivery system is nearly identical to the C5 corvette.
The Fuel Pump Speed Control module (located behind the splash guard over the left/front wheel well) starts the fuel pump in the left side tank when the ignition is engaged. There's a secondary fuel pressure regulator in the left tank sender unit. The fuel pump contains a reverse flow check valve. This valve (along with the two pressure regulators) maintains fuel delivery pressure to prevent long cranking times.
Replacing the fuel pump is a big job as there's a lot of interference that has to be removed before the tank can be disconnected and removed to access the fuel pump. Unless you have a lift and access to all the tools, (after the proper diagnosis is made) I'd drive/flatbed the car to a dealership and then open your wallet wide.
Last edited by ccclarke; 05-01-2016 at 06:27 PM.