Fuel smell in cabin and trunk...resolved

I wrote this as a new thread topic because many folks encountered this issue, and there are many places where fuel leaks can occur. If it is not obvious and you have fuel smell in the trunk, then have your mechanic smoke pressure test the fuel cell to help find the leak point.

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* Encountered the fuel smell in trunk and cabin
* Attempted to trace and resolve for about 12 months
** Trunk emits fuel smell when opening trunk
** Fuel smell comes into cabin when windows are down
* Finally had local mechanic perform a smoke pressure test into the fuel cell
* Found a hairline crack in the driver side float valve
* Spent a lot of time searching for these float valves new; none came up
* Called FerrParts and Russ sent me a used 2001 456M GT float valve
* Installed float valve by same mechanic, smoke pressure tested. No smoke leaks
* Drove for about 7 miles today. No fuel smell in the trunk. No fuel smell in the cabin
* I am stupid; I should have had this smoke pressure tested after all the obvious locations were traced.

 

456 never came with a fuel cell. It is a conventional fuel tank. Fuel cell is something entirely different.

 

What is a "float valve"?

 

I suspect he is speaking of the roll over valves. Most common point of leakage is any of the Ferraris of the period.

 

I was under the impression the 456's didn't have rollover valves, but the 550's did.

 

OK

 

As Brian knows, 2000 MY and later 456Ms, of which this is one, had roll-over valves just like the two seaters.

 

Item 54 = part number 100260 = Left hand valve float

FUEL TANK -VALID FOR USA M.Y. 2000 AND CDN M.Y. 2000- - Ricambi America, Inc.

hairline crack where the plastic nipple joins the body

 

Dead cheap as well.

How is the smoke test performed on a fuel tank?

 

I'll take a guess, it's the same as the process for the engine, it low pressure smoke introduced into the tank air space, probably via the fuel filler.
If was a leak you'll see it, as was evident with my fuel pump mount backing plates.

 

Would it not vent through the designated vents? How much bar would you need to build in order for it to work? 2 or 3....

 

For EPA reasons no vapours are to enter the atmosphere, from this my understanding the fuel system is effectively sealed and uses the engine vacuum to draw vapour into the carbon canister.
As for pressure very low 2 or 3 psi is quoted for engine tests.

 

Thank you for the info.

 

Confusion comes from Ferraris lousy manuals. The same part is assigned a different name depending on what book you look in. For those that do not have any idea what the parts do it is confusing. 328 manuals show a diagram titled "Hydraulic Clutch" and show a picture of the cable operated clutch. Some still argue some 328's had a hydraulic clutch. 360 manual shows crank timing sensors as "Angolar Speed Sensor" and some argue it is really an angolar speed sensor, whatever that is. Ferrari in their never ending quest to be cheap contracted out to an ESL school to do their manual translations with predictable results. I very often read, to the degree I can, the Italian version as it gives you a far better chance of getting correct information. The difference in message is sometimes quite eye opening.

 

The pretty pictures are the most helpful.

 

* Mechanic said he used 1 psi to smoke test fuel tank
* Mechanic requested to have about a 1/3 of the tank filled with gas...or less, when I brought the car in
* Drove the car 30 miles today. No cabin fuel smell. No trunk fuel smell.

 

I love a happy ending. Especially with one not ending in flames.

 

Even more so when the part costs $4.