Annoying Fuel odor in Daytona

Fuel tank could have a crack and is seeping fuel between the tank and its outer coating. I have seen this before and it is hard to trace but makes a lot of smell. As always the smell of fuel means a fire is just around the corner so you would want to have it looked at with immediate effect.

 

A lot of possibilities... and smell could be a "the chicken or the egg ?" thing.

 

There are a lot of places in the trunk that could produce a leak. It could be the fuel level sender, the upper vent tube that runs from tank to tank, or the lower tank to tank cross hose/tube or the fuel filler neck hose or the fuel pick up hose. Pull out the spare tire, look at the lower cross tubes, mine were hard as a rocks and weeping. Oh I don't have a Daytona, I have a GTC but it's pretty much the same design.
Check out the parts manual, you will be shocked at how many possible leak points there are within the trunk.

Forgot one, the fuel return tube.

 

If hoses are soggy, replace.

 

Diagrams of the Daytona fuel system on the Eurospares web site including 1972 revision in the link here: https://www.eurospares.co.uk/parts/ferrari/365-gtb4-daytona-1969/fuel-system/fuel-tanks-piping-41642



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good my dear nice post

 

check all the hoses for the fuel venting system.....make sure they are good and they are not exiting into the trunk.....

had this on a gtc - there are at least 2 that vent the fuel system that i know of

 

that 365 diagram above is similar to the GTC....i see at least 3 vent ports on the filler neck....then all the connections

might merit replacing all those lines if they have never been off!

 

I’ve had pinholes from rust in carbed vehicle’s steel lines that would pass vapors, but not enough fuel to leave sign where you could see it.

 

It is a bundle of fun to remove tanks and to do the project, if you "know what you are doing"...

Clearly, I am stressing the: "know what you are doing".

Regards, Alberto

 

"... and with 45+ year old car and whole bunch of related components, it can easily escalate from there."

 

Some years ago we had a similar problem with a smelly Daytona and we traced the problem to a corroded fuel return pipe which was leaking, it was along time ago but from memory said leaky pipe ran back from the carbs through ( I think ) the left hand side lower sill panel or rocker panel back to a fuel tank, happy hunting, cheers Kev.

 

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Yes indeed, this was one of my old steel fuel pipe that went through the sill, that was dry rust that came out of it. I have no idea how the car still ran! they were replaced with a stainless steel ones.

Also a common problem are the big nuts that bolt the fuel pipes onto the carbs, if the car has been serviced then they need checking a few weeks after or after a hot then cooling down cycle. There is a thread on the type of washers best suited to fix this problem.
For a trunk smell I would be looking for a pin hole in a tank often caused by the spare wheel rubbing on one of them.

 

Grant, that tube (pipe) itself is not used for fuel delivery. It's a housing or support inside the coachwork for the fuel 3/8" hose that runs in continuous length from fuel pumps to fuel rail by the carbs.
Mid-to-late production cars also have another one like it for front-to-rear brake line tubings, fuel return line tubing and in US-delivery cars one of the fuel tank fume delivery (breather) line to the charcoal canister in the engine bay.
This "another one" is what owners should be more cautious of since it too traps moisture/water/etc like the one in your photo and in 45+years can rust all those small steel pipes/tubes running inside.
I've experienced/seen (original) brake line tubes break due to rusting inside those tubes on more than one Daytona.

 

Yes Timo.
mine is a late car so it has the 3/4 dia tubes inside the sill and inside them it has the small bore now stainless steel tubes, one from the pumps to the carbs the other return from the carbs to the tank inside the trunk.

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Large bore ducting tubes inside the sill

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Here's two new tubes I made during restoration of a mid-production car along with the OE tubes they replaced...
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Perhaps a somewhat moot point, but I did deviate from OE design by adding small drain holes at the lowest spot on both.

 

My problem was very strong gas smell in trunk..problem was large yellow hose was leaking at one end at the metal fitting,Timo was most helpful in locating this material.which then needed to have the old metal fitting attached..problem solved..Chuck

 

Did you ever locate the source of the smell? My Daytona smells of fuel when 100% full but not otherwise, any thoughts on this?

 

in the cabin or when trunk is open?

 

Not in the cabin and not in trunk. I just crawled under the car and the glass fuel filter housing was wet with fuel. I literally, for the first time, just put a full tank of gas in the car, I wiped off the fuel filter housing and will check in the morning. There was about a tablespoon of fuel on the garage floor this morning. No real smell in the trunk at all, but I think the yellow hose is original, thoughts?


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