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Tech notes on fuel odor

Finally found the article that made me check the check valve. This goes into some additional stuff and may be something you want to do, but just futzing with the valve and cleaning it fixed the problem for me. Worth doing...so much nicer to drive without the fumes.
This is from the compilation of Owner's Technical Notes Series from the AROC. I hope I have not stepped on any toes by posting this. It is a very handy publication with lots of fine tips and guidance.
Good luck, Jonathan
 

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Hi, I bet the gas smell starts when the tank is less than 1/4 full. I deal with this by not letting the gas go lower than that. Anything else I would say is a serious problem. I think the other thread mentions the check valve in the trunk, correct?
 

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I did the stuff as described in tipo101's attachments (thank you for posting them) and can say that after 3-4 days, with any amount of fuel in the tank, it does work.

No more stinky trunk, no more wafting gas smell. Do note however that temperatures around here have been slightly cooler, so that may or may not be a factor in the results I got.

The only down side that I can perceive right now is with the removal of the metal check valve at the vapor tank there's a risk of fuel leaking if you turn the car upside down. (so don't turn the car upside down, or you may burn as well along with being crushed)

It wasn't neccisary to use a pin through the restriction thingy up at the intake tube end of things, as between the size of the opening in my plastic manifold and the size of the hose from the vapor tank, a regular bit of vacuum hose (1/8" ID and 1" long per description) jammed into the orginal hose did exactly the same thing without need for any additional stuff to keep it in place. (it's tight in the hose and the nipple hole on the plastic manifold is just small enough to prevent the 'add in' piece from being sucked into the engine)

It only takes a few minutes to do the whole job, and definitely worthwhile trying if you've got odor problems going on.

Worse case scenario is that it won't work and you'll have to revert back to the stock set-up. (well, that and the whole 'flip the car and leak gas' thing too, but I don't expect that happens all too frequently.....)
 

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Discussion Starter · #25 ·
Tipo101,
thanks for posting this info. Thanks Tifosi for your shared info. I'll study this drawing the next few days(I do things slowly, but thoroughly), and see if it will be a fix for my situation. I will keep you advised of my success or not. Thanks!
Joe
 

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i would go the other way on this one on the gas cap. Turn it tight, then loosen it a turn or two. Too much pressure and it looks like your alfa is peeing.
 

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2 tanks of gas later, top up, top down, warm, cold, short trip, long trip, and still no odor of gas in the trunk or cabin.

I'm a happy camper about the lack of 'essence' but still slightly let down as now that it doesn't reek my wife wants to ride with me again.

This puts a damper on how I drive ('stop doing that, it's annoying and you're going to get pulled over'), who I wave at (chicks dig the convertable), and the places I go ('I want to go to the mall, not some bar or diner 30 miles out of town on backroads')


Just one of the sacrifices I guess we have to make now and again....
 

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Hi all - I have a horrible gas smell when driving. I note Tifosi’s attachments but they refer to ‘82 onwards? I have a ‘78 Spider. The basic of basics (which I love, btw).

A bit of background - the car hadn’t run for 3 years (busy irl). Had a fuel pump problem. All sorted now - runs smoothly but the smell of gas is horrific.

Just replace all of the hoses and double secure each connection with 2 clamps. So...replaced all hoses in the engine compartment as well as the connection in the boot (from tank to metal tube).

Still...gas smell in cabin.

Thoughts?
 

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Hi all - I have a horrible gas smell when driving. I note Tifosi’s attachments but they refer to ‘82 onwards? I have a ‘78 Spider. The basic of basics (which I love, btw).

A bit of background - the car hadn’t run for 3 years (busy irl). Had a fuel pump problem. All sorted now - runs smoothly but the smell of gas is horrific.

Just replace all of the hoses and double secure each connection with 2 clamps. So...replaced all hoses in the engine compartment as well as the connection in the boot (from tank to metal tube).

Still...gas smell in cabin.

Thoughts?
Those instructions on checking the fuel system would apply from at least 71 on and perhaps the 69 models as well. Is your check valve present and working?
1645315
 

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Thanks. The problem is (and I AM a pretty handy guy :), Im not sure what the “check valve” is/where it is. Is it part of the unit (including the fuel gauge) that is placed within the tank? Because I’ve now replaced everything between the tank and the carbs (Dellortos, which I’ve rebuilt)....
 

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Thanks. The problem is (and I AM a pretty handy guy :), Im not sure what the “check valve” is/where it is. Is it part of the unit (including the fuel gauge) that is placed within the tank? Because I’ve now replaced everything between the tank and the carbs (Dellortos, which I’ve rebuilt)....
your 1978 european (carburettor) spider will most likely not have all that check valve, vapour recovery stuff....that is for injected cars.

is it more a smell of raw fuel or exhaust fumes?
what you could check is the rubber gasket on the fuel sender on top of the tank...at least check the 6 screws are tight...if it looks wet there, replace seal.
Also make sure the little drain tube on the 'filler boot' is clear when you open the filler flap...that tube runs inside the trunk and out again....it can split just as it exits the trunk (it gets kind of squashed just at the exit point and can split or it can even fill up with dirt, then any fuel just collects in the dirt, like on a sponge)..run a stiff wire down there or carefully pour some water down and make sure it flows out freely under the car.

this is a Bertone, but same idea:
Fuel Boot Drain?

does your 78 have downturned exhaust tips?
Is the boot (trunk) seal good?
 

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SpiderSerie et al,

The best thing about my Alfa is I continuing learning new things about her. A "filler boot drain"? Wow.

Ok, so you are correct that I don't have all of those vapour recovery devices - thus my confusion.

There is no leakage from the top of the case tank and the screws are quite tight. That that filler boot drain just empties into the boot (!). Look at the pics - I do not see a the place where it should be positioned to exit from the car. So this is likely the culprit. Just need a bit more insight into how to reposition it...
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Quick follow-up. I jammed this fuel drain hose into the body wall, as shown. tested with a bit a water - yes, it drains out near the wheel.

So i suppose all sorted? Will let you all know. Oh, and I will replace the fuel neck hose as it does show signs of cracking.

As always, THANKS! The Alfa community is the best!

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If you smell gas after filling up, it could also be a cracked/torn boot (the one that surrounds the filler neck where it meets the body). As these cars get old, the rubber parts dry out. Since the coupler between the filler neck and tank is cracked, you may want to spend a little time and money and replace all the hoses and rubber seals.
 

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If you smell gas after filling up, it could also be a cracked/torn boot (the one that surrounds the filler neck where it meets the body). As these cars get old, the rubber parts dry out. Since the coupler between the filler neck and tank is cracked, you may want to spend a little time and money and replace all the hoses and rubber seals.
Thanks - this is what I'm doing. All parts already ordered. Will check back in in a few days after I've renewed bits and bobs!
 

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Don't over tighten the screws holding the sending unit to the tank. Just make sure they're snug.
 
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