Hi All,

Two weekends ago now I set up my FD to be stored in the garage over the winter. Stabil in the gas, air in the tires, etc. etc. - the usual drill. I added one step to the process - I depressurized the fuel system by following the RX7.org instructions of pulling the circuit relay while the engine was running (which died almost immediately), and then releasing the gas cap to vent pressure out of the tank.

https://www.rx7.org/Robinette/release_fuel.htm

I elected to do this because since buying the car in September, there's been an intermittent fuel smell after driving the car and shutting it off. I know this is a red flag - I haven't driven the car much, and always with a fire extinguisher, but I could never ascertain where it was coming from. The FPD, at the time, wasn't emitting obvious signs of leaking, maybe an injector o-ring, who knows. The smell seemed temperature dependent, as the car could sit un-driven for 2 weeks of 50 degree days, and then when the temps shot up to 70+ one day, the smell returned - so I assumed it was a hairline crack in a rubber hose that expanded and contracted.

Well, fast forward to today, and now the car is obviously spilling gas directly under the motor so perhaps the FPD was the culprit and it finally went out for good. The thing is, it's *still* leaking gas, 2 weeks after being de-pressurized. What am I missing? How much gas could there really be in the area of the FPD? Are the above rx7.org instructions wrong and there's still gas that needs to be sucked out of the system somehow? The immediate ignition cut was obvious, not sure if it had enough time to suck all the gas out of the lines/FPD. Any tips appreciated!

 

Even after de-pressurizing the system you can still get gas trying to come out. The gas in the tank expands with temperature change and will push gas into the system.

Best thing to do would be pull the upper intake manifold, jumper the F/P and GND connector in the diagnostic box, and turn the key to On. That will run the fuel pump and you can look, listen, and feel for the leak. Find it and fix it while it's down for the winter.

If you don't have time/resources/whatever to fix it right now, you can pull the fuel feed and return lines off the rat's nest under the throttle body - this is where the metal hard lines from under the car have a short hose connecting them to the rat's nest. Disconnect the lines, find some bolts that can plug the lines, and hose clamp them in place.

Oh, when you pull the fuse to depressurize the system, the car runs until there isn't enough fuel to keep it running. At that point *there is still fuel in the lines*, it's just not at 37 psi or whatever. Probably just a few PSI.

Dale

 

Make sure you've got the fuel cap off, and I usually put a small funnel in the filler neck, so that the little flapper is open and venting.You can also pull the line at the fire wall, and plug it with a bolt and a clamp.

 

Thanks for the replies from you both - I think I will attempt to pull/plug the feed & return lines as you described to get this to stop. The leak with the car just sitting there, is somehow getting worse. Here's a pic from about a few days ago of the paper that was under the engine bay:



The dark patch on the left is oil from my leaking pan, and the lighter patch on the right is gas. Here's a pic from today from a fresh sheet of paper that was there since last night, and that's pretty much all gas.



So the car definitely does not want to keep any gas inside of it, and I'm guessing the leak is such that it's pulling vacuum/gas back into the line(s) just for it to leak out more, and worse.

 

Second this. I have my motor out for a rebuild and capped the lines at the firewall. When I left it overnight, came out to the garage to find it pushing gas out the lines at the firewall. The bolt I had in the line wasn't good enough to seal.
Anyways, the system definitely builds pressure just sitting. Crack the gas cap to alleviate the pressure. Since leaving the gas cap open I've had no problems and I don't smell any gas.
You've got a leak for sure though if you can smell it with everything connected. Fuel Pulsation damper on the firewall side of the primary rail is a usual culprit.

 

Thanks for this confirmation - pulled the gas cap a few days ago (huge release of pressure) and have left it off. Leaking/smell is much, much less now - but still occurring, likely due to the FPD as you mentioned. Just glad I was able to mitigate it a ton, and can use one of the days coming up to really dig into it.