Need help accessing Ferrari 456 rollover valve and vent valve

My fuel tank seems to have an over pressure problem. I am trying to access part nos. 3 and 32 on this diagram to test and/or replace them. I removed the panel covering the gas tank and can see that these are located on the left side up inside a hole under the rear deck, but I can't get my hand up there to access them. Has anyone replaced these? Do I need to remove the tank or will removing the rear deck work or is there some other way to access them? Thanks very much. Image Unavailable, Please Login

 

I'm just learning about this, but there is an evap system to keep gas fumes from escaping into the atmosphere (part of the smog system). If the evap system has a clog or a valve doesn't release pressure that builds up in the tank then you end up with an pressurized fuel tank, which causes fuel leaks and worse. This thread explains it better than I can:

https://www.ferrarichat.com/forum/threads/gas-cap-air-rushing-out-upon-removal-when-fueling-normal.445716/

 

Thanks very much for responding, that is helpful.

I did have a slight fuel smell in the trunk, not the cabin. I thought I got rid of it by changing the four fuel lines, but when I filled the tank back up it seems to have come back, but is not very noticeable. I am thinking that the over pressurization is causing the smell by forcing out a small amount of fumes or fuel out as I cannot find a leak. So I plan to fix the over pressurization and then decide if I need to smoke test the system. As I have to take the tank out to get to the rollover valve, I'm going to start by checking to see if the charcoal canister is blocked, which would also cause the over pressure. If that is ok, I'll have to pull the tank and check the rollover valve etc.

Thanks again.

 

I'm still working on mine, but here is an update. There is an access panel on the driver side rear wheel that allows access to the rollover valve and other items without removing the fuel tank. You jack up the car. Remove the wheel, remove access panel, remove two screws holding the separator and all of it comes down as one unit. You may have to remove one of the vent hoses to the fuel tank to get it out.

On my car it appears it is the vent valve that is the problem. Rollover valve seems fine. I just received a new vent valve today. I will install it tonight and report back. Thanks to all that provided help and info.

 

The earlier diagram I posted was actually for a later car. My car has the system shown here. My over pressurization was caused by the vent valve, #13 in this diagram. I was able to get a new one from Algar. Problem solved. Image Unavailable, Please Login