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-   -   Jeep wrangler gas in oil (http://www.wranglerforum.com/f210/jeep-wrangler-gas-in-oil-213412.html)

Felber 01-19-2013 02:38 PM

Jeep wrangler gas in oil
 
Somehow gas keeps getting in my oil. I recently just changed my oil a few hundred miles ago and it already smells strong of gas. Also the oil level is now high. I removed the fuel rail looking for a leaking injector but could not find one. I don't know what to do, maybe buy all new injectors? My jeep is a 99 wrangler with the 4.0. Any help would be greatly appreciated! Thanks

The Green Machine 01-19-2013 03:16 PM

IIRC the 4.0 had a problem with the head between 99 and 01. Maybe that would be a good start to look for.

Atthehop 01-19-2013 03:22 PM

I suspect a leaky injector.

CaseInternational 01-19-2013 04:34 PM

Diffidently sounds like an injector. They are pretty cheap for gas engines so I would replace them all. Even if only one is leaking, the rest cant be too far behind in being worn out so I would just do them all for piece of mind.

Make sure there is no pressure left in the system, them un-bolt and remove the fuel rail. There is an o-ring on the top end where the fuel rail sits on top of the injector and one o-ring on the bottom where the injector goes into the intake manifold. It will be a little stiff lifting the fuel rail off and getting the injectors out. When you go back together put some grease on the o-rings and they will slide into the intake manifold and fuel rail a whole lot easier. Make sure there are no fuel leaks, just turn the key on and let it pressurize the system and you will be good to go. Its really a pretty easy project.

The injector leaks on the inside and when it should be off, fuel seeps/leaks past into the cylinder and washes down into the crankcase. Since all the injectors are pressurized all the time, if one leaks it just runs into the cylinder. When the injector should be open the computer sends a signal to the injector and it energizes a solenoid to open the injector and let fuel in, when the computer stops sending the signal then the injector closes. You wont see a leak just by removing the fuel rail as it is not leaking externally.

Jeff

The Green Machine 01-19-2013 05:15 PM

No kidding. The gas leaks past the piston rings, and into the crankcase! I would figure in that scenerio, the motor would just be flooded out, hard to start, and disguise itself to be a stuck open fuel pressure regulator. I am no tech though, so....

The Green Machine 01-19-2013 05:30 PM

I had a stuck open fpr on a v-6 that would'nt start, and after it filled the cylinders with gas, it then poured out of the air filter housing and onto the ground. This was on a cold motor too, so the piston rings had not expanded. I never thought to check the oil for gas in it.

Felber 01-20-2013 12:14 AM

Is there any way to know for sure if its a leaky injector. i removed the fuel rail with the injectors attached and none of the injectors leaked.

The Green Machine 01-20-2013 12:59 AM

How Does Gas Get in Engine Oil? | eHow.com

Here is what I found for you with a search on yahoo.

CaseInternational 01-20-2013 07:52 AM

Quote:

Originally Posted by Felber (Post 3251625)
Is there any way to know for sure if its a leaky injector. i removed the fuel rail with the injectors attached and none of the injectors leaked.


Did you have pressure to the injectors while they were out? Don't quote me on the pressure but most fuel injected engines run 30-45 PSI of fuel pressure. It could behave differently with fuel pressure applied than with none.

The only way on a fuel injected engine fuel could get into the oil is through the injectors. There are no internal passages for fuel. its not like a carburated engine where you can adjust things like the float level, a float sticking, needle and seat, ect.....

Do you have a fuel pressure gauge? You could see what the fuel pressure is while the engine was running. There is a pressure regulator some where in the system that controls pressure and if it was malfunctioning allowing to much pressure, each time the injectors opened it would allow more fuel to enter. One would think that would be caught by the oxygen sensors as it would read high and try and back off the amount of time the injectors are left open to compensate for it.

I had a 98 Dodge 2500 with a 5.9 gas that was filling the crankcase up with fuel. It also had very poor fuel mileage and the exhaust smelled rich. I bought injectors off the internet for a hundred bucks or so and put them in and it made a whole new pickup again. Fuel mileage went up and no more fuel in the oil.

Jeff

jgorm 01-20-2013 10:07 AM

How many miles? Have you pulled the spark plugs to see what they look like? Before you go spend ~$300 on injectors that may not be the problem, run a compression test and take a look at the plugs.

The Green Machine 01-20-2013 01:23 PM

Quote:

Originally Posted by jgorm (Post 3252504)
How many miles? Have you pulled the spark plugs to see what they look like? Before you go spend ~$300 on injectors that may not be the problem, run a compression test and take a look at the plugs.

X2 on that. I would run a compression test.


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