Fuel Smell on start up with A/C on

[rgorke]

04 LS V8 with 227k miles.

On Friday, taking my spawn to school we had a really bad fuel smell with the A/C turned on. Turning off the A/C there was no smell in the cabin. I had added a quart of oil (Mobil 1) the day before and spilled a bit around the fill spout. I had heard that synthetic oil can smell like gas. I cleaned up the residual oil and no more smell all weekend. This morning, no smell until I turned on the A/C and the fuel smell is back.

Fuel filter is only 6-9 month old so I am ruling that out. I filled up earlier in the week so I am ruling out any issue with the tank, especially since I don't smell anything until the A/C is on.

I am letting the car sit and cool and will look and smell around to see if I see anything.

I have searched the forum but haven't seen anything that matches my issue.

Any thoughts on specific locations to investigate? I am thinking fuel rail. Also, my fuel pressure is 58, is that high or where it should be?

 

[joegr]

That's normal pressure. Are you sure that it's really fuel, and not oil? (burning synthetic oil does not smell like gasoline to me)
It seems like the fresh air inlet for the AC is picking up underhood fumes. It shouldn't do that. Check the gasket between the hood and the cowl.

I once had that something's leaking smell, but I could only smell it when outside the car. It started just after an oil change. I found it to be a plastic bag that had blown up on the exhaust in the back. It was melted in. It took several months for it to burn off enough to stop smelling.

 

[rgorke]

That's normal pressure. Are you sure that it's really fuel, and not oil? (burning synthetic oil does not smell like gasoline to me)
It seems like the fresh air inlet for the AC is picking up underhood fumes. It shouldn't do that. Check the gasket between the hood and the cowl.

I once had that something's leaking smell, but I could only smell it when outside the car. It started just after an oil change. I found it to be a plastic bag that had blown up on the exhaust in the back. It was melted in. It took several months for it to burn off enough to stop smelling.

Thanks, it smell like gas to me, even to my 11 year old. I will double check the gasket and make sure there aren't any leak OR plastic bags!!! What was weird is that I didn't smell it at all over the weekend...

 

[grizzlyls]

Any Gen1 owners that read this and have a gas smell look at the 'silver button' damper on the fuel line in your engine compartment. Big safety hazard there, why you see You tube vids of Tbirds an Ls's on the side of the road in flames with no damage. I just replaced mine, which is the now discontinued fuel pipe. Lincoln Support says it can be any generic damper, but good luck getting anyone to touch it for liability reasons.

 

[rgorke]

I just went out and started it up looking for any drips or smells. Nothing. No smell with A/C on either. I'll have to wait until morning to see if there are any drips.

Gas mileage doesn't seem to have suffered. I averaged 24 up to Santa Barbara at 75 mph.

 

[joegr]

Any Gen1 owners that read this and have a gas smell look at the 'silver button' damper on the fuel line in your engine compartment. ...

If I remember correctly, it's attached to the underside of the fuel rail on the 2nd gen, on the driver's side.

 

[Sparkplug51]

04 LS V8 with 227k miles.

On Friday, taking my spawn to school we had a really bad fuel smell with the A/C turned on. Turning off the A/C there was no smell in the cabin. I had added a quart of oil (Mobil 1) the day before and spilled a bit around the fill spout. I had heard that synthetic oil can smell like gas. I cleaned up the residual oil and no more smell all weekend. This morning, no smell until I turned on the A/C and the fuel smell is back.

Fuel filter is only 6-9 month old so I am ruling that out. I filled up earlier in the week so I am ruling out any issue with the tank, especially since I don't smell anything until the A/C is on.

I am letting the car sit and cool and will look and smell around to see if I see anything.

I have searched the forum but haven't seen anything that matches my issue.

Any thoughts on specific locations to investigate? I am thinking fuel rail. Also, my fuel pressure is 58, is that high or where it should be?

It is the main fuel line that goes to the rail. My 04 dies the same thing. Not all the time but when it does it gives the same smell like yours. Next time , open hood , turn key on and check the line. Also look at the valve cover. If it's a fuel leak the cover will be very shiny under the fuel line. Still haven't found out how to repair or fix without having to replace the hole fuel rail system

 

[rgorke]

I think I have narrowed it down to the fuel pressure sensor. It had a little bit of fuel on it yesterday.

 

[rgorke]

I wanted to loop back and tie up this thread...I had an extra fuel pressure sensor, installed that one and it leaked worse than the one I had on there. I unwittingly ordered one from the vendor that another member said he had trouble with. In the meantime, I was able to pick up a very slightly used one off a Gen 2 that a member of one of the Facebook groups had recently crashed. (I also go his sport coils and shocks off that car with less than 60k miles on them...will explain in other thread). He said that he had replaced the FPS not long before the crash, so it is pretty new.

When I started to replace the FPS, the vacuum nipple on the existing one snapped off like, well, something that snaps off easily. I put the replacement sensor on and not only do I NOT have any fuel smell, the car idles much much better on cold start up. AND, it appears my ST and LT fuel trims are where they should be. (I previously had recurring lean codes pop up but only when the car was cold.) So, maybe the FPS was the source of the slight vacuum leak...It appears it may have been!!!!