Thread: '03 Cadillac CTS Fuel Pump Sender with '95 LT1 engine

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I'm looking for an OEM split gas tank to mount in front of the rear axle in my 37 Buick.
It has been suggested on a different website that I could use a Cadillac CTS fuel pump module and siphon system with my '95 LT1 engine. Could use with CTS tank or two smaller tanks.
I believe my '95 LT1 engine has a return fuel line from the fuel rail. From what I read about LS1 engines of the 2000s era, they did not have the return line.
1) Does anyone know if Cadillac CTS fuel pump assembly has a return line from the fuel rail?
2) If the CTS system has a return line, how would I connect my 95 LT1 fuel lines to the 2003+ CTS fuel pump? (Since connectors are different)
Forgive me if these seem like simple questions, this is my first project car.
Thanks

Fuel pumps don't have a return line, unless it's just a fitting on the mounting plate. It's still not part of the pump, just a separate fitting on the mounting plate.

If your engine has a return line, there should be a pressure regulator attached to the back end of the fuel rails on the engine that sends the fuel back to the tank. The tank will have a return fitting on it.

From what I've read, the CTS pump supplies the correct 43 psi.

Newer engines, like the LS series need 58 psi. There is still a return line, but it comes from a fuel filter/ pressure regulator located near the tank, that sends excess fuel back to the tank. That system eliminates a lengthy return line, like the older systems use. I have an LS3 in my car and it uses the newer filter/regulator system. The filter/regulator is mounted right by the tank and has less than a foot of return line.

The link below has a diagram of the fuel rail and pressure regulator location on an LT1.

Fuel Injection Basics - Tech Article - Chevy High Performance Magazine

Originally Posted by daveS53

Fuel pumps don't have a return line, unless it's just a fitting on the mounting plate. It's still not part of the pump, just a separate fitting on the mounting plate.

If your engine has a return line, there should be a pressure regulator attached to the back end of the fuel rails on the engine that sends the fuel back to the tank. The tank will have a return fitting on it.

From what I've read, the CTS pump supplies the correct 43 psi.

Newer engines, like the LS series need 58 psi. There is still a return line, but it comes from a fuel filter/ pressure regulator located near the tank, that sends excess fuel back to the tank. That system eliminates a lengthy return line, like the older systems use. I have an LS3 in my car and it uses the newer filter/regulator system. The filter/regulator is mounted right by the tank and has less than a foot of return line.

The link below has a diagram of the fuel rail and pressure regulator location on an LT1.

Fuel Injection Basics - Tech Article - Chevy High Performance Magazine

Thanks for confirmation that a CTS fuel pump will provide the correct pressure.
My 95 LT1 has the fuel pressure regulator on the fuel rail and it is vacuum driven and has a return line.
I'm having trouble finding detail on if a 2003 CTS has a fuel pressure regulator on the fuel rail, or fuel pressure regulator near or in the gas tank.
Does anyone know where the fuel pressure regulator located is on a 2003 CTS?

You may need to spend some time at a Cadillac dealer's parts department. I researched some online sources that have some exploded views of the fuel system, but they are not very good. At least one supplier mentions the fuel pump including a pressure regulator, but they also list a pressure regulator for sale. Those pumps are pricey, if one ever breaks.

I think that lengthy fuel return lines from the engine have been eliminated on more modern GM engines. I believe that my filter/pressure regulator with a return fitting dates back to a '98 Corvette. It's now sold as part of a kit for LS engines, by Speedway and Summit.

Thanks for your help.
Found the attached description of 03 CTS fuel system. From this description the fuel pressure regulator is on the fuel rail and there is a fuel line.

Found this tank for 04 CTS and it looks to me like there is only one fuel connector which I believe to be typical of LS engines.
04 05 cts V LS6 Engine Fuel Tank Gas Plastic Tank w Pump Sender Used | eBay

Wikepedia lists 6 engines available so maybe the LS6 versions have no return line and others do. Still need more info to know for sure.
2.6 L LY9 V6 (gasoline)
2.8 L LP1 V6 (gasoline)
3.2 L LA3 V6 (gasoline)
3.6 L LY7 V6 (gasoline)
5.7 L LS6 V8 (gasoline)
6.0 L LS2 V8 (gasoline)

Take a look at the E-bay photo. The fuel filter looks similar to the one I have on my car. There are three fittings. One is the pump output to the filter. The other one on the same end of the filter is the return. The other end is the outlet fitting. At least with mine, the pressure regulation is done within the fuel filter. Mine is a WIX 33737.

WIX Filters Fuel Filters 33737 - Free Shipping on Orders Over $99 at Summit Racing

Here's a link to the correct 3-fitting fuel filter.

http://www.partsgeek.com/catalog/200...el_filter.html