Help! Fuel Smell??

[Renzo O.]

Alright, time to request advice from someone with more C3 experience.
1969 427 4 speed w/Tri-Power Holleys. Just bought it last month. It had been in climate controlled storage for 20 years or so.

Major fuel smell (even in the cabin when driving) that seems to be coming from the Pass side of the engine. Have looked and put my finger under every fitting from the carbs down to the fuel pump with no leakage. Also pulled the dipstick and put a lighter to it and it doesnt ignite so I dont think it's the pump diaphragm.
Has a noticeable, occasional pop when idling which I am assuming is the throttle plate bushings. Going to send the carbs out for rebuild pretty soon but I wanted to drive it a bit first. Cant imagine its that though. There would be a vacuum on them so I wouldnt think that would contribute to the smell.
Kinda scared to drive it too much with the strong fuel smell though. Anything you guys know of that I am not considering??

[Steve B.]

Re: Help! Fuel Smell??

Renzo, since you say it seems to be coming from the passenger side, a leaky fuel pump may be the culprit. If the fuel pump is the issue, please do not drive the car until its fixed.

[Renzo O.]

Re: Help! Fuel Smell??

That's the route I was going to go even though I dont see leakage and because it's relatively cheap. Got to be a leaking diaphragm. If it was something else, I'm assuming I'd see a lot of dripping. Thanks!

[David H.]

Re: Help! Fuel Smell??

... and put my finger under every fitting from the carbs down to the fuel pump with no leakage....

Renzo

You did this leak check with engine at idle or off?

By chance has fuel pump been replaced? Fuel pressure at idle should be 5-7 lbs as I recall.

Any chance fuel smell source is seepage on line from tank or tank to line join?

Dave

[Philip A.]

Re: Help! Fuel Smell??

Seems like you covered all the basics. However you didn't mention if you smell it while it is running or freshly shut off? Say about 10-15 min or a little longer.
If you have no visible sign of drips check the fuel line rubber connector hoses for small cracks and seepage. The only other possibility would be if the floats are sticking and it is dumping fuel down the carbs when it's running. But if thats the case it will start fouling the plugs pretty fast. It could also be the idle circuit leaking fuel into the engine when it's shut off causing the fuel smell.
More info needed.

[Floyd B.]

Re: Help! Fuel Smell??

I had a strong gasoline smell whenever I ran the car ('69 390HP) and parked it in the garage. The smell would linger and eventually fade away after about two weeks. If I started the engine, the cycle started all over again. I eventually located the leak: it was the the brazed-on flare nut fitting on the GF432 fuel filter.

[Renzo O.]

Re: Help! Fuel Smell??

I have done the check starting with engine cold, then while it was idling, then when warm/off. Cant find any moist areas around the fuel lines/carbs. Gonna try a fuel pump, I guess! Not going to drive it with that strong of a fuel smell.

[Renzo O.]

Re: Help! Fuel Smell??

Possibility..I only went back as far as the fuel pump so far. Gonna jack it up tomorrow and see what I can see. Thx

[Renzo O.]

Re: Help! Fuel Smell??

Seems to be running pretty well except for the occasional POP from what I think is the throttle plate bushings being old. I would think it would be blowing some black smoke if it was dumping fuel and it's not. I am going to probably send the carbs off and have them reconditioned shortly anyways, but I was hoping to drive it a bit first! Since its been sitting so long and I cant see any leakage, I think I'm going to try a fuel pump. That will give me some peace of mind long term anyways. I dont trust what may be a 20 year old rubber diaphragm enough to risk my car to it. I have a bunch of the receipts for this car and I dont see one for a fuel pump! Thx!

[Renzo O.]

Re: Help! Fuel Smell??

Posting a reply on this just for posterity. What I ended up finding was the short 12" long fuel line going to the fuel pump. The rubber was old and inflexible and one of the clamps was a bit loose. It was enough for the fuel to coat the line on the outside causing the strong fuel odor, but not enough to drip. Hope that helps someone someday!

[Mark E.]

Re: Help! Fuel Smell??

Thanks for posting what you found. I wish everyone did that.

[Tom M.]

Re: Help! Fuel Smell??

Good find. It was mentioned earlier to drop the spare and check the fuel line to tank hose since it may be in the same crusty condition.

[Renzo O.]

Re: Help! Fuel Smell??

I'm gonna do that. Thanks for bringing it up.

[Mick D.]

Re: Help! Fuel Smell??

Thanks for posting this, I think I may have the same problem. Fuel smell while parked in garage.

Posting a reply on this just for posterity. What I ended up finding was the short 12" long fuel line going to the fuel pump. The rubber was old and inflexible and one of the clamps was a bit loose. It was enough for the fuel to coat the line on the outside causing the strong fuel odor, but not enough to drip. Hope that helps someone someday!

[Mick D.]

Re: Help! Fuel Smell??

I have the exact same issue, I’ll check the lines and see what’s up. I also do not have a rubber gasket on my fuel cap so maybe that could also cause it?

I had a strong gasoline smell whenever I ran the car ('69 390HP) and parked it in the garage. The smell would linger and eventually fade away after about two weeks. If I started the engine, the cycle started all over again. I eventually located the leak: it was the the brazed-on flare nut fitting on the GF432 fuel filter.