How long should it take for a FPR to leakdown to 0?

[flbuick]

Hey guys, I've got an Accufab adjustable FPR and 60# injectors. Occasionally, I smell gas from the garage hours after I driver her. There are no leaks from the fuel system. However, the FPR reads 0. So, my question is: How long should it take for a FPR to leakdown to 0 when the car is shut off? Currently, it is less than an hour.
My assumption is that as the FPR leaks down, the fuel sits on the closed valves and past the open valves and I get the gas odor in the garage.
Thanks for the input.

 

[pacecarta]

that wouldnt be a fpr leak down but rather an injector leak .
fwiw a fpr doesnt have to seal the return flow 100% to work ,

if you smell fuel you probably have a small leak some where

 

[flbuick]

Thanks for the info. I'll take another look for a fuel leak

 

[pacecarta]

1/2 hr or less is typical for pressure to drop but ive seen some hold longer

 

[Chuck Leeper]

Gas smell is common, if the charcoal canister has been removed. The vent line originally hooked into it. The open vent, even w/ a gas filter in the hose, will stink.
Pressure leak down can also be caused by the check valve in the fuel pump leaking.

 

[flbuick]

Thanks for the replies guys. Yes, the charcoal canister has been removed. Leakdown time varies. It takes 45 minutes to an hour. So, it sounds like this is normal.

 

[TURBOPOWERED68]

On my car ---- Also cheap aftermarket rubber / steel braided lines will let the fuel vapor seep through it the line it self.
Once i went with the Teflon lines -- no more fuel smell.

 

[pacecarta]

open vent will definitely cause fuel odor , if you plan to store in the garage put the canister back on the vent

 

[RUQWKNF]

Most people, when they upgrade the pump, eliminate the factory pulsator dampener that goes inline between the stock pump and the hanger, and just use a straight piece of fuel injection hose. That dampener does help keep the feed line and fuel rail pressurized. Without it, fuel simply flows back through the pump. Now, whether it is a serious restriction or not in potential flow, I have never seen, but I'm sure RC has in all of his pump testing. This loss of prime can also affect how quickly the fuel rail pressurizes and how quickly the car starts. IE: a couple of spins, vs 7-9 spins before lighting off. The others are right about the fuel vent hose and removal of the charcoal canister, as well as rubber hoses allowing vapors to escape over time. Injectors leaking down also helps depressurize the rail. I have watched fp drop on a car without the pulsator dampener, in just a few mins.
YRMV.

-Patrick-

 

[pacecarta]

the check valve is in the pump neck not in the pulsator

 

[turbofrank]

Let car idle for a while run fingers along fuel rail and connections, same with fuel filter area. might want to drop tank to check connections and tank seal.

 

[greeneyegi]

When I had the fuel smell in garage it turned out the filler neck on fuel tank leaked. It really only smelled when tank was full or close to it.If half tank it wouldnt smell.

 

[flbuick]

Good point greeneyegi I did just fill it up last Saturday. I went over the fuel rail area when it was pressurized and didn't find any wet areas. I don't get the odor often but she is stored in the garage and it can stink up the house cause the A/C air intake is just inside the door from the garage. I'll see if it happens next time I fill the tank. Thanks for all the input guys. We were having some cool dry weather here and I don't have to tell you how much these cars like that kind of weather. Of course, the tires don't like the cold weather... But I digress; after a spirited drive I parked her in the garage and later that evening I noticed the fuel smell. Thanks again for the info