sevinn

Hey all,

I'm looking for the best way to empty out my fuel tank (well, as much as necessary) so that I will be able to change my fuel pump tomorrow. If I have been reading right, the fuel crossover function relies on the pressure from the main pump, which is dead in my car. I can probably siphon out the driver's side fuel, but that leaves the passenger side completely full. Will gravity allow the fuel to crossover if I jack the passenger side of the car up? Any other ideas?

Thanks

JesseBBB

Real good write up, hope it helps.

http://forums.corvetteforum.com/c6-t...fuel-pump.html

Motorhead-47

Don't worry about the passenger side tank. With the main pump dead there is no easy way of getting the fuel out of the passenger side. You won't be removing that tank anyhow. I do suggest you drop the 5 bolts on the aluminum pan under it (passenger side) to give you a wee bit of play in the crossover tube but if you use a jackstand and a short piece of 2x4 to support it you'll be fine. Siphon all you can from the driver's side and just be prepared to handle the extra weight as you lower the driver's side tank. Each gallon is going to be about 7lbs and you'll probably end up with a gallon or two still in the tank. No biggie IMHO.

Good luck with the swap.

Pack Leader

I made this relatively cheap for draining fuel from boats. Find a cheap 12V pump and hook the suction line to your fuel line. Should work...

AORoads

wow, bad news. hope it goes well for you.

sevinn

Thanks this is what I was hoping to hear.

That's a great looking system Pack Leader, I'll have to do something similar, and thanks for the wishes of luck AORoads.

I thank you all very much.

sevinn

Got it all swapped out but now have a "Service Fuel System" CEL. My sending unit was good before the swap, and we were very careful about installing it correctly and being gentle when reinstalling. I'm hoping I'm getting the CEL because we plugged the pump in before actually installing to make sure it fired up. Gonna go try to get the code cleared tomorrow, but as of now my gas gauge is buried at 0 and I get the CEL. She runs though, that is all that is important to me at this point. I can get it to somewhere more convenient (ie, not my driveway) if I have to change the FSU.

One issue we experienced during the install that we didn't forsee was that the lines were actually coming out of the tank when we removed the crossover tube, making it VERY difficult to get that thing uncoupled.

Motorhead-47

You probably don't want to hear this but it's likely that you did not have one of the two fuel sending wires that plugs into the connector on the underside of the large pump flange fully engaged in it's lock. If this happens, when you plug in the harness it simply pushes the sending unit wire out of the connector on the underside. This translates into a do-over on the R&R of the tank.

Recommend you pop the wheelwell liner loose, unplug the 4-pin fuel pump harness and put a multimeter across the two center pins of the fuel pump side of the harness. If you have an open circuit then you have your likely culprit.

I speak from firsthand experience on this type of mistake. When I pulled mine apart for the same exact symptoms you are describing, I found one of the two fuel sending wires was loose. I reconnected it, pulled on both of them a few times to make sure they weren't going anywhere and then took a small wire tie and secured all of the fuel pump wires together.

Motorhead-47

This was an A4 tranny car?

sevinn

It will be frustrating if that really is the issue. Probably the most care was taken at the time when we had to move the FSU over to make sure we didn't break any little plastic bits. We marked one of the green wires to make sure it went into the same slot on the new pump as the old, and when we plugged it into the new harness, both wires "clicked" and then we tugged on them a bit and they seemed snug enough. I will check into this today, but unfortunately my jack sprung a leak just as we were finishing up. I'm still hoping I'm getting the CEL because we plugged the pump in to test it with no FSU connected, as unlikely as that scenario is.

Yes, A4. We didn't have to drop the cradle, just the exhaust, the wheel liner, and loosened the passenger tank. Everything was a very tight fit, but it was definitely doable without removing anything. I don't know if the A4 has more room on top/around than the A6 though.

Thanks for the info again.

RicK T

Following with interest. You guys willing and capable of doing this stuff are an inspiration. Best of luck.

AORoads

Agree, and hope it is an easy fix!

sevinn

Thanks guys. Unfortunately I will have to check into this tomorrow. A buddy of mine called and needed some help changing the starter on his truck so that used up most of my day today and I also have to go get a new jack in order to get to the connector. I will update again tomorrow!

Thanks for the interest and support.

Motorhead, I must especially thank you. Everything would have been much more difficult without your advice and pictures.

Motorhead-47

...it's what this hobby is all about. Let me know if you need further assistance with the fuel gauge diagnosis. A multimeter across those two fuel sending unit connections will probably give you the answer you don't want.

You are seeing a fuel gauge on the dash that is buried on "Empty" right?

RicK T

Yes......he wrote it in his post #7:

sevinn

Correct, never changing 0 fuel. I don't remember what it used to do when I started it up, cause frankly I never paid attention, but at startup it goes full (I remember that) then hangs just under half, which seems like the level of fuel that would have been left in the car after I was finished siphoning gas out initially.

The good and important part is that the car runs and drives perfectly, and I get just over 60# at the rails. I'm going to take it to a mileage that is sufficient to be sure that all crossover is working properly (ie. get it to under 1/2 tank).

sevinn

Looks like it is definitely a do-over. I was able to do a continuity check on the level sensor wires and the test failed. The sensor must have been on its way out because I am 100% confident that it is hooked up right. It just doesn't like the new pump.

AO-08

i'm pretty sure GM changed the direction of the level sender card. That being is is 40-250ohm.
i think 250 used to be empty and 40 full. i believe they swapped this direction. If that is the case then it could be your problem. The car expects the Left tank to always have more fuel than the right. If the right reads more then the left for too long it will give error code.
good luck and let us know what you find.

sevinn

Great news...

/sarcasm

Tonight the wife and I had a few errands to run so we first stopped for some gas (I JUST received my new fuel level sensor today) and went on with our errands. As we are leaving walmart, well trying to, I go to start the car and guess what? She stumbles and dies. Looks like I have ANOTHER fouled pump, just after filling with fuel. I wish these things would happen at home. It sucks that walmart is only about 1.5 miles away from my house, but I will have to get it towed to get it home.


I'm really quite upset with this car right now.