Jayfabs

so today I swapped my pump on my c6z. After the install everything seems fine but I can only fill my tank halfway. One thing I noticed and maybe did wrong was on the cross over tube the bottom hose I noticed the o ring was on the male part so I left it there. During install I pushed it all the way to the back of the male tube. I was reading a thread somewhere and a guy was talking about a ferrule but I didn't see any. Maybe it's possible the o ring is to far back and not sealing. During the install of the cross over tube to the driver tank it just slid right together no hassle. I'm going to dive back into it tomorrow to see if I can see anything.

Unreal

Car only takes 8 gallons or only shows 1/2 full?

If you can only fill 1/2 way mechanically, sounds like the overfill valve was damaged, or lines messed up. Since that has nothing to do with the little lines/orings at all.

Jayfabs

As I thought about it more. It is probably not those lines but I'm not sure about the ferrule in the bottom line so that might still be an issue.

I drained both tanks by jumping the relay so they were both pretty empty. There might have been a gallon left in driver side when I pulled it out. I completely emptied it once out. Once everything was back together I poured in about 4-5 gallons at home and then went to the gas station. I could only add 8.7 gallons there. Once I started the car it shows just below 1/2 tank full. Also the first 4-5 gallons showed 1/4 tank full.

I did install the float once the pump was already in so that might be a problem. It wasn't easy to get in. I did it that way because I used an after market sock that stuck out the bottom so seemed easier at the moment to install float once pump was half way back in the car.

Jayfabs

Ok I just dropped the tank. So it seems that the passenger tank is mostly full. I drained the tank again by jumping the relay and a hose from fuel rail into gas can. However it seems I only drained the driver tank the passenger did not. The o rings are back in place and seems like the ferrule is there so don't think that's an issue.

Jayfabs

I just pulled everything apart nothing looks abnormal.

Jayfabs

Ok I just got everything back together. Everything seemed fine. I turned the car on without starting it and I can see it shows 1/2 tank but I know the driver side is empty. I'm going to go fill it up again. I think it one of those things that because I messed with it the computer has to readjust. We will see

Unreal

Sounds like siphon is not working. Those orings/ferrules will mess that up. So when you are pumping them dry, it is just sucking from drivers tank.

Passenger tank should empty first.

Jayfabs

so I believe the second tank has small pump in it. I could here is barely pumping gas over to other tank when car was in on position.

Unreal

No it does not. It siphons using those lines, using pressure off the pump in drivers tank. Any leaks/etc and it won't siphon. There is no pump in the other tank, just a siphon driven off the main side.

Jayfabs

I thought I read there was a jet pump. (Ok I did some more research it is a siphon like you say. There is just a part called the siphon jet pump) It shows full now. We will see if I run out of gas prematurely. From what I read the computer should see an issue and warn me that there is a problem. Atleast it will work for now and I can order the new parts if an issue arises. Thanks for your help!

schpenxel

Fuel pressure has to be over 50psi or so for the siphon to work. If you tried to just unhook a hose and turn on the pump it will only drain the drivers tank since it won't build enough pressure to enable the siphone pump. There's a valve in the passenger tank that controls this.

Jayfabs

thanks for the info! That's makes me feel better. I had a hose setup on the front of the fuel rail. So not sure how much pressure was actually there since it was a wide open flow.

schpenxel

Yeah it wouldn't have been enough pressure IMO

3X2

More than likely the crossover pipe is not sealing causing all the fuel to transfer into the right tank and not back to the left. The seals for the crossover go into the tank opening, the black ferrule goes in after the o-ring with the taper facing towards the crossover. I lube them with silicone grease, same goes for the o-rings where the pipe goes into the tank. Verify all 4 nipples are on the crossover. Make sure you push the crossover straight into the tank, then rotate the lock ring to secure.

Jayfabs

when I took it a part the o rings and ferrules were in the correct spots. So far everything seems ok. Only at 7/8 th of a tank just need to drive some more to find out.

rabrooks

its easy to get those pipes in the cross over tube misaligned. Even if the ferules and double orings are in the right place. Those inner pipes switch from top to bottm as they go from one side to the other and they are supposed to have a spiral twist in them. I think you need to remove it all and examine it properly.
Good luck.

3X2

OP, did you remove the crossover pipe or just disconnect it from the left side tank? If only disconnected, are the two inner pipes still locked into the metal tube and are the nipples that go into the small o-rings intact (not broken off)? I have also seen the plastic tubes that connect to the fitting break off the backside of the fitting that those small o-rings go into.

Jayfabs

I only removed the driver side tank I did not take the cross over pipe out. I did take it apart again and double checked everything. It seems to be normal now but won't know till I drive it more and use the gas up.