I have a leak somewhere from my PS tank when I top off with gas AND I autocross (tossing fuel around in the tanks). If I fill 3/4 and I autocross I have no issue.

I can only assume it is something to do with the crossover tube. My crossover is rubber and my question is, does fuel flow inside that rubber tube from PS to DS tank, or does that rubber hose contain smaller fuel lines which transfer the fuel?

I've tried to find pictures/diagrams of the early style fuel system and see what parts may need to be replaced but coming up empty.

 

Well, I found this description and image:

02 Fuel System Description
Two fuel tanks containing 9 gals each store the fuel supply. An electric fuel pump attaches to the fuel sender assembly inside the left fuel tank. The fuel pump pumps fuel through the fuel feed pipe (6) and an in-line fuel filter (9) to the fuel rail. The rear fuel feed pipe (6) has an integral check valve (4) in order to maintain the fuel system pressure in the feed pipe. The pump provides the fuel at a pressure greater than what is needed by the fuel injectors. The fuel pressure regulator, part of the fuel filter (9), keeps the fuel available to the injectors at a regulated pressure. A fuel return pipe (7) returns the unused fuel to the left fuel tank. The fuel pump also feeds the fuel through a tee (5) with an orifice in the fuel feed rear pipe (6) and through the auxiliary fuel feed rear pipe (2) in order to supply the siphon jet pump inside the right fuel tank. The siphon jet pump transfers the fuel from the right fuel tank to the left fuel tank through the auxiliary fuel return rear pipe (3, 8).:





So it seems there are no fuel flow nor any lines inside the rubber hose???

 

What is my tank setup then? If it's not the one pictures and it's not the new system with pumps at the top of the tank.

 

Goggle tons of pic. Theres only 2 set ups this one and the top pump thats.

 

You have to look at the RPO's for FFS. If you have FFS then you have newer late 2003 and 2004 fuel system.

 

I have the early style as I have physically looked at my car and the pumps are on the bottom of the tanks...my VIN is prior to the cutoff for when the newer style systems came out.

Someone in another thread mentioned when gilling up at the pump, the PS tank is filled first then overflow into the DS tank. So it seems the rubber hose does not contain any "lines" but does pass fuel from tank to tank. Maybe when my tanks are full and autocrossing the fuel level is high enough to leak somewhere.

 

I have an early 2003 (November 2002 build) that has the earlier tanks. Unlike the later tanks, there are no lines in the hose, all are external lines. My passenger tank leaked at the molded seam on top where the emissions lines are attached. I could reach the top of the tank through the right wheel well after removing the inner fender. So I could see the leak, but had to remove and replace the tank with another one as the seam was not repairable.

 

Thank you for the confirmation. I will try to remove the PS liner and see what I can find!

 

I have an early production 2003 Z06 and just developed a big fuel leak on the nylon fuel lines exiting the fuel pump and fuel filter where they loop over and inside the frame rail on the driver side. Am thinking about adapting the hard line fittings and use AN fittings and braided hose.

I was looking at the OP's diagram and description of the rear fuel line setup. I have a couple.of questions though.

1) Line #6 shows to have a check valve in line ( I have found a 6AN check valve I can put.inline)...but the description says that the Tee has an orifice in it....does anyone know the diameter of this said orifice? Is it really necessary? Does the orifice feed the side of the Tee that supplies fuel to the passenger side tank siphon jet?

2) the return line coming from the filter appears to be 5/16" line....would it hurt to use 6AN line at this location? Or, will that affect the pressure regulator and cause issues?

The reason I am thinking of converting to braided hose with AN fittings is that if the nylon fuel lines are no longer available then any used parts are just as old as what is on my car....

Thanks
Floyd

 

I'm not sure the purpose of the orifice in the line that is near the DS tank. I thought the siphon jet was in the PS tank.

I'd assume any check valve will be OK as it just keeps fuel from running "backwards"

I wouldn't think a larger return line would be a bad thing. It would only lower the pressure in the line between the filter/regulator and the tank. I think as long as you keep pressures/flow within spec on the feed side, the rest is along for the ride.

 

Yes...the siphon jet.is in the passenger side tank....looks like on the pump outlet pressure feed line is where the Tee is located and it feeds fuel to the filter and passenger side tank to the siphon jet....just not sure what diameter the orifice is that the schematic description is talking about at the Tee

I am going to start pulling the lines loose on the fuel pump and filter/regulator in the morning...hopefully will see which line has cracked or split where they run up through the frame rail....hope to get this resolved...

I'm sure it probably started leaking the last time I drove the car a couple of weeks ago...but didn't notice it and lucky it didn't result in a fire...

Finally spotted the leak this past Monday when I started the car and let it run for 15 minutes just to circulate the fluids...went out to kill the car and could smell fuel and saw it dripping in front of the driver rear wheel....

 

Be thankful you have an early style fuel system LOL. I would HATE to pull tanks for a fuel pump.

 

yes...you are exactly right about that...at least the fuel pump is accessible. From what I have found from searching my car was produced in early November 2002 and was 600 cars before they made the change to the newer C6 style fuel system...got lucky on that.

Good news is we found the leaking line and got it temporarily fixed. Took about 2 hours total time to pull all three lines to inspect them.

We pulled the fuel lines yesterday morning and found the leak on the return line coming from the passenger tank back to the driver side tank. the hole was right where the the nylon lines run down into the top of the frame rail down to the fuel pump hat. we spliced that line with a quick connect union as a temporary fix. My friend who has the lift we put the car up on to work on it is going on vacation for a week this coming Friday. When he gets back we will replace all three lines that comes off of the driver fuel pump. I have gotten all of the hose fittings... braided hose...Tee fitting for the one feed line and the check valve that goes inline to the filter... also got a new filter/regulator to put on at the same time. Just hoping we can snake all three braided hoses back through that slot in the frame rail...its gonna be a tight fit.

its not a cheap fix.....with all of the hose and necessary fittings and new filter...I am in it for just over $300 in parts. But....the alternative of buying used factory nylon lines from Corvette salvage people just does'nt really make sense because they are just as old as what is on my 2003 car. So, I guess I will just have to bite the bulleton this repair.

 

Glad you got it sorted out.

I'm very familiar with your situation. Spent many an hour under it messing with my fuel system when I went E85 and looing at all the lines. I would be curious about fitting braided lines up through that frame pocket if you can get the AN line to bend.