An update and some tips for anyone that needs to replace the fuel pump on a late series C5 (2003 on) with the code FFS. On this type (and C6) the fuel pump is mounted on top of the driver side fuel tank and the only way to change it is to remove the tank.
To do this, Chevrolet recommend lowering the transaxle first. This is not necessary. There's an excellent thread on how to remove the tank on a C6 on the Corvette Forum How to replace a fuel pump - CorvetteForum - Chevrolet Corvette Forum Discussion
Most of this applies to the C5. Mine's a C5 auto and it is definitely possible to remove the driver side tank with the transaxle in situ.
(If you need to remove the passenger side tank (eg to change the sender unit) I'm not sure that's possible on the auto as there is other stuff in the way of the cross-tube on that side. I didn't need to do this so didn't spend any time trying. There may be a way of doing it. If you have a sender issue you could try a fuel additive first. I've heard that can be successful).
So, back to changing the pump. Follow the procedure on the above link but note the following:
1. Stating the obvious, make absolutely sure the pump needs replacing! I did all this only to find that when I connected the pump directly to the battery it worked. My problem was a different electrical issue. If your pump doesn't work, first check and clean all the relevant earth connections. Try a direct battery connection to the two larger wires in the harness plug behind the rear wheel arch cover (grey live, black earth). If that works remove the pump relay and bridge where terminals 87 and 30 would go. This should operate the pump when the ignition is on. This could also work as a get-you-home if your relay packs up. See this for relay testing info: //youtu.be/z_E8-D2IVKs
2. If your pump is running but noisy or you want to upgrade it for a modified engine, use the pump to drain the fuel first as described in the link. I tried various combinations of tubes to try to syphon out the fuel only to find that there is an anti-syphon device blocking the way and I couldn't get past it. Removing the tank with 6 gallons of fuel is not fun. I used a trolley jack to take the weight but it's certainly easier if empty.
3. Jack the car up as far as possible. The tank is about 2 feet tall. Use axle stands.
4. Disconnect both rear silencers, loosen the centre hangar, disconnect the driver side rear exhaust mount and move the tail pipe out of the way.
5. When you get to the point of disconnecting the cross-tube, have patience. It's not easy, you'll swear a lot, when you can't do it first time (or second or third....) best to have a tea-break and go back to it. The link's description of moving the black clip and undoing the cross-tube collar is puzzling to read but clearer when you're doing it. It's pulling the cross-tube out that feels impossible! The cross-tube is corrugated but almost impossible to pull back the required approx 20mm. In addition to the above link, undo the passenger side tank cover bolts and wedge some wood between that tank and the chassis to pull the cross-tube over as far as possible. I then looped a small rope around the middle of the cross-tube and over the diff. If you go feet first from the back of the car so your head is under the diff you can pull the rope with your right hand to put a bend on the tube while pulling the cross tube out with your left.
6. With the cross tube out you can see the vent pipe connection above it. That is also difficult to disconnect. Spray with WD40, practice on the similar connection by the filler neck. I selotaped a screwdriver bit to my thumb so I could depress the latch enough to remove it, had another tea break and finally got it off.
It's a bugger of a job but I got there. Have patience and it can be done. (But best avoided if possible)
To do this, Chevrolet recommend lowering the transaxle first. This is not necessary. There's an excellent thread on how to remove the tank on a C6 on the Corvette Forum How to replace a fuel pump - CorvetteForum - Chevrolet Corvette Forum Discussion
Most of this applies to the C5. Mine's a C5 auto and it is definitely possible to remove the driver side tank with the transaxle in situ.
(If you need to remove the passenger side tank (eg to change the sender unit) I'm not sure that's possible on the auto as there is other stuff in the way of the cross-tube on that side. I didn't need to do this so didn't spend any time trying. There may be a way of doing it. If you have a sender issue you could try a fuel additive first. I've heard that can be successful).
So, back to changing the pump. Follow the procedure on the above link but note the following:
1. Stating the obvious, make absolutely sure the pump needs replacing! I did all this only to find that when I connected the pump directly to the battery it worked. My problem was a different electrical issue. If your pump doesn't work, first check and clean all the relevant earth connections. Try a direct battery connection to the two larger wires in the harness plug behind the rear wheel arch cover (grey live, black earth). If that works remove the pump relay and bridge where terminals 87 and 30 would go. This should operate the pump when the ignition is on. This could also work as a get-you-home if your relay packs up. See this for relay testing info: //youtu.be/z_E8-D2IVKs
2. If your pump is running but noisy or you want to upgrade it for a modified engine, use the pump to drain the fuel first as described in the link. I tried various combinations of tubes to try to syphon out the fuel only to find that there is an anti-syphon device blocking the way and I couldn't get past it. Removing the tank with 6 gallons of fuel is not fun. I used a trolley jack to take the weight but it's certainly easier if empty.
3. Jack the car up as far as possible. The tank is about 2 feet tall. Use axle stands.
4. Disconnect both rear silencers, loosen the centre hangar, disconnect the driver side rear exhaust mount and move the tail pipe out of the way.
5. When you get to the point of disconnecting the cross-tube, have patience. It's not easy, you'll swear a lot, when you can't do it first time (or second or third....) best to have a tea-break and go back to it. The link's description of moving the black clip and undoing the cross-tube collar is puzzling to read but clearer when you're doing it. It's pulling the cross-tube out that feels impossible! The cross-tube is corrugated but almost impossible to pull back the required approx 20mm. In addition to the above link, undo the passenger side tank cover bolts and wedge some wood between that tank and the chassis to pull the cross-tube over as far as possible. I then looped a small rope around the middle of the cross-tube and over the diff. If you go feet first from the back of the car so your head is under the diff you can pull the rope with your right hand to put a bend on the tube while pulling the cross tube out with your left.
6. With the cross tube out you can see the vent pipe connection above it. That is also difficult to disconnect. Spray with WD40, practice on the similar connection by the filler neck. I selotaped a screwdriver bit to my thumb so I could depress the latch enough to remove it, had another tea break and finally got it off.
It's a bugger of a job but I got there. Have patience and it can be done. (But best avoided if possible)
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