I am a new member with a low mileage SRT6 Coupe, purchased earlier this year.
I only recently filled the gas tank to FULL. I did not overfill and there was no spillage and overspill line is clear anyway.
When I parked the car in my garage for a while there was a smell of gasoline around the car. As noted this is not an overfill issue and there are no fuel drips underneath the car.
The problem goes away completely once the tank is down to 3/4s full.
Suggestions from members as to the possible cause and remedies.
Thanks.
Ian

 

Check the hoses to the charcoal canister.

 

There is also a seal on the fuel gauge on the top of the tank
Some gas pumps shut off later than others and it can cause the fuel to touch the top of the tank and leak out around that seal
If the smell goes away after the tank is used a bit it's likely that fuel pump seal that is leaking when the tank is full

 

Thanks for the ideas I will look into them.

 

I find it odd that you can have such a 'break in the system' and not have a EVAP code and Check engine light.
ANYTHING that allows fuel vapors to escape is enough to cause the evap test to fail - that's what the evap test does - it pressurizes the tank and then measures how long it holds pressure. If it leaks down too fast, a code is set and your CEL comes on.

BUt if there is fuel seepage in the fuel lines/pump/regulator, there would be no EVAP code. Consider what happened with my car:
I had the smell of fuel vapors around my car at times - never IN the car, just around the car. Then one tech day in GA, when the guys were changing my differential fluid, they noted that the fuel pump had stains around it's seams.
Nick started my car and let it run ten minutes or so, and he saw it - fuel seepage, VERY SLIGHT, from the seam in the fuel pump.

I just find it odd that you can have fuel vapors escaping without an EVAP code being generated. Consider other possibles, if you cannot find an EVAP leak.

 

Thanks for the thoughtful response.
I confirm that I have no check engine light coming on and have seen no Code being generated other than a driver's side airbag light that I am working on separately. Question: How long would the Code last? i.e. as the fuel drops to 3/4s full and the gasoline smell goes away would the Code disappear then? i.e. should I test for the Code when the tank is full? Or would the Code last longer?

I did have a slight hiccup of power delivery when driving the car while the engine wasn't fully heated up when accelerating slowly around 1,500 - 2,000 rpm. Could this indicate a gas cap with a faulty seal? And Yes I have ensured the fuel cap is properly screwed on. But this slight hesitation seems to goes away by itself.

 

Well, as I think about it, the EVAP test only happens between 1/4 and 3/4 full. And it happens periodically, not sure how often.
So if the tank is really full, the test is suspended due to the fact that you have too little air in the tank for a good test.

Drive the car and let it get down to 1/2 tank and you should, eventually, see the CEL and get a code, if there is a leak.

No matter the level in the tank or the condition of the EVAP test, the car should run fine, the fuel pressure is regulated to 58psi, so the engine should never see variations in what is going on in the tank.
Now, if pump or filter/regulator are screwy, then the pressure may vary and SURE the car will act up then. The engine will idle down to about 20-25psi, and you can drive the car down to 35-40psi, but it won't run right and it wont like throttle positions beyond maybe 1/4 open. Ask me how I know!

This is the one I have:
https://www.summitracing.com/parts/o...apHx7F7TXogjjc

Measuring fuel pressure is easy - the kits are $30-90 and are easy to use. I have one at home and have used it three times in five years.

 

Thanks for the update and that's one useful tool so thanks for the link.
Re a leak around the fuel pump. Would not this happen ALL the time the car is running (and be quite dangerous)? In my case the fuel smell is ONLY when the tank is quite full and then the smell goes away as fuel level reduces below about 3/4s full.. Makes sense to check it out regardless.
Quite perplexing especially with no codes. It seems that empirically ruling stuff out may get me to an answer...eventually! Sigh.
It's been raining here for a few day so when we eventually get some sunshine and the roads dry out, I will put a few more miles on the vehicle

 

Check fuel filler neck hoses and connectors.

 

I did not say "leak", I said "seepage" and "stains". VERY LITTLE fuel was escaping, but enough I could smell it at times.

It takes VERY little gasoline to generate an odor.

If its ONLY with a very full tank, I'd suspect the seal around the fuel level/pressure sensing connector (center, top of tank) or the filler neck area.
Im still surprised that the EVAP test is not failing and generating a CEL and code.

 

A few drips from the pump nozzle as you take the nozzle out of the filler can sit in the gas filler cap compartment and it takes a while for it to evaporate. I have had it happen, not enough fuel to reach the overfill drain tube but you sure cab smell it but not in the car.
you could smell if the gasket between the car body and the compartment was leaking. That gasket has leaked before.

 

Where have you been all week, Dave?

 

Thanks for the suggestion.
I don't believe this is the issue as the fuel tank was filled 3 weeks ago. Small run off would have completely evaporated within a day or 2 at the most. I had checked anyway and the area was 100% dry.

 

I have not been able to work on the car recently. I did buy a new gas cap before taking the car for a drive yesterday.
Ambient temp was 80F and all was 25 minutes into the drive (car engine fully warmed up).Gas tank a smidgen under half full of 93 octane and no gas smell.

I entered a residential area with speed limits on the streets of 20 and 25 mph.
I stopped at a Stop Sign and then executed a 90 degree left hand turn feathering the gas pedal with rpm 1,500 - 2,000 (so I did not speed). Almost immediately after the car turned the corner with no further gas pedal movement my car became a VIOLENT BUCKING BRONCO! Power On power Off, power On Off and repeat the loop multiple times within 4 seconds with perhaps 1/2 second between ON and OFF repeats, until I backed off the gas pedal and moved to a fortunately open parking space along the road. I was lucky not to be hit by a car which came up behind me. I rested the car for 30 minutes and when I returned and it drove perfectly smooth with no hint of what had just transpired. It was amazing how scary this incident was as it was so violent. Note the rpm did not jump at all, but it was total OFF and then back on re the power in the most violent form imaginable.