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Fuel rail loses presure.

2K views 5 replies 4 participants last post by  dweeber 
#1 ·
Hello group.
I have a 05 TJ Rubicon (stock) with 240,000 km's on it. Recently I noticed that the fuel rail is losing pressure. It used to start right up when turning the key. Now I have to wait a few seconds before cranking it, to get it to start right -up.

When I drive it, then park, I can smell gas near the engine bay. Yikes it's leaking somewhere. Anybody got any ideas of where to look or how to detect the location of the leak. I've kept my engine bay clean over the years. looking at the the injectors and connections in the fuel line. The leak isn't obvious to me.
Thanks in advance for any ideas
Cheers
 
#2 ·
Does it run rough for a short time when it fires up? Or does it run smooth. Have you tried cycling the key a few times before cranking? Then does it fire right up?




Most of the time it's the fuel pump bleeding back. If you had a rough run for a few seconds then I would suspect a injector.
If you just have a external leak you could jump the fuel pump relay and let it sit with it not running while watching for leaks. This would pressurize the fuel rail but the danger would be if a injector was leaking you could potentially fill the cylinder with fuel.
 
#3 ·
Ok I just started it today and it doesn't seem to run rough at all,a little higher rev's until it warmed up.
When it is cold. If I spin the key right over to crank, it spins a few seconds before it fires up. If I turn on the ignition, wait a few seconds, then crank it. It fires right up. I'm guessing the pump is re-pressurizing the fuel line. Most times I can smell gas coming from the engine bay after I park it. I did a on-line search and it was mentioned it could be the o-ring seal between the rail and injector. I looked closely at the connections but couldn't see or smell anything obvious. The computer isn't throwing any codes like an evap leak etc..
 
#4 ·
If you have a o-ring seal leaking it would be hard to find as the fuel would evaporate as soon as it leaks. You used to be able to buy a o-ring kit that gave you the lower and upper injector O-rings. If you can find parts replace them as they are 14 years old.


My self I would get it hot then with the engine off jump the fuel pump relay and see if you could find a leak.


I still would suspect your fuel pump is bleeding back but solve one problem at a time. A fuel leak would be the priority.
 
#6 ·
I had the same problem and just put in a new pressure regulator yesterday which immediately solved the problem. It's NOT an easy install, you basically have to take down the gas tank. It's a $17 part which would take 2 hours or a couple hundred dollars to have replaced.
 
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