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Discussion Starter · #1 ·
My son has a 1995 Wrangler 2.5 and he is getting gas in his oil. I have replaced the injectors and the fuel pressure regulator. I checked the plugs and they all appear to be firing. Any ideas?
 

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:welcome: to the Forum..:wavey:
 

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Welcome to the Forum wdevereaux,

Sorry I can't help with the oil in gas that your son is experiencing. Other posters with fuel injection systems might have some suggestions.
However, I suggest not driving the Jeep until you get it repaired. The diluted oil won't be able to do it's job of lubricating the internals and could cause a catastrophic failure.

Good Luck, L.M.
 

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If its bad enough to notice Id guess its either flooding a cylinder or cylinders and would run pretty crappy on start up. If it was carbed I say bad fuel pump diaphragm but being FI the only place its dumping fuel could be into the cylinder directly. I cant even imagine this, but have the vac lines been jacked around like the fuel tank vent line getting hooked directly into the crank breather line and not the charcoal canister or some kinda mess like that? should be a vac line schematic on under the hood.
 

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Find a post by Got it at last. In his signature there's a free link to several Factory Service manuals and a couple Factory Parts Manuals.
Open that link and click on the manual that you need.

If the vacuum schematic is missing or unreadable, you should be able to find one in the Factory Service Manuals that are in the link that Got it at last provides.
In any case, the FSMs are real handy when diagnosing problems with our old heaps.

Good Luck, L.M.
 

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How well does the engine run, smooth, rough, misses? How do you know gas is in the oil? Dipstick oil level indicator? How long does it take for gas to get into the oil? Leaking injectors is the ONLY way, but you say they are new? I will add that a ruptured fuel pressure diaphragm could also allow gasoline into the engine. More info please........
 

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^^ this before speculation
 

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Discussion Starter · #8 ·
I know that its gas because it would have a milky appearance if it were coolant and there has been no change in the coolant level, it also has a gas smell. It is about a qt. a week. I plan on doing a compression check of the cylinders this evening. I pressure tested the fuel rail and it dropped to zero very quickly when the engine was shut off. I also think Ill go for new plugs but, I don't think that's the problem either.
 

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Dang, a quart a week isnt good. Im not sure how long it takes to bleed off rail pressure but it should only take a second or two to build pressure once the key is turned to on. Was this the reason you swapped out the injectors and regulator to start with? So two sets of parts and the same issue? Also, being its that bad if you let it sit a few days, then pulled the plugs and turned it over you might find one cylinder blowing out fuel and be able to pin down at least where its leaking in from. Another concern is if it sits and it's one cyl that's flooding, then after a week of sitting id be concerned of bending a rod, think hydro lock, when you go to crank it over.
 

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The other alternative could be cracked head. I can't see gas going thru an injector when the engine is shut down, gas will evaporate pretty quickly in a hot combustion chamber.
 

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Is the jeep being driven in short spurts? I don't know for certain, but I'm thinking that gasoline will evaporate rather quickly from a warm crankcase. Is the CCV valve functioning?

From what I understand from reading the above posts, is that after a weeks use, the oil level on the dipstick shows to be 1 qt. over full. Is that correct?
What do you do then? Change the oil or drain 1 qt. of oil/gas mix?

If that were my Jeep, I'd stop driving it until I had the source of gasoline in the crankcase cured. Gasoline vapors are highly flammable. If they find a source of ignition (spark or hot exhaust manifold) you could have a greater problem than gas in the oil.

Keep us posted on what you find and how we can help.

Good luck, L.M.
 

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Wow! A quart per week?? That's some serious leakage. The fuel pressure should NOT drop like that. Have you pulled the vacuum hose off of the regulator with the engine running to see if fuel is coming out of the regulator? If it's not that, an injector is stuck wide open. Good luck,,,,,, let us know what it is.


EDIT: The only other possibility that I can think of is that someone mistakenly connected the fuel tank vent hose to a direct vacuum source........???
 

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Discussion Starter · #13 ·
Plugs were just replaced. All are firing.Compression test showed 178-180 psi in all 4 cylinders. manual calls for, between 155-185 psi so. bottom end seems fine. I tested the new fuel injectors by removing them and connecting them to the fuel rail and cranking the engine. they all work fine and do not leak after shutdown. I'm thinking of replacing the head. Is it possible that the gas could get by a stuck valve? Any ideas would help. I really dont want to spend $500 on something that will not make a difference but, Im out of ideas.
 

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I can't see any way a cracked head or any issue with the head would cause this.....

No, if you had a stuck valve you would have low compression and a knocking sound.

Any chance the fuel pump is running while the engine is off?
 

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Plugs were just replaced. All are firing.Compression test showed 178-180 psi in all 4 cylinders. manual calls for, between 155-185 psi so. bottom end seems fine. I tested the new fuel injectors by removing them and connecting them to the fuel rail and cranking the engine. they all work fine and do not leak after shutdown. I'm thinking of replacing the head. Is it possible that the gas could get by a stuck valve? Any ideas would help. I really dont want to spend $500 on something that will not make a difference but, Im out of ideas.


No, it's not possible that a stuck valve is causing this. What about the other things that I suggested earlier? Have you checked into that thoroughly?
 

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If it doesn't cost too much, you might send a sample of your oil to a lab to see if there is truly gasoline in the oil.
I don't know how accurate a sniff test might be. Your son might simply need an oil/filter change.

From what I understand from reading the above posts, is that after a weeks use, the oil level on the dipstick shows to be 1 qt. over full. Is that correct?
What do you do then? Change the oil or drain 1 qt. of oil/gas mix?

Good Luck, L.M.
 

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Plugs were just replaced. All are firing.Compression test showed 178-180 psi in all 4 cylinders. manual calls for, between 155-185 psi so. bottom end seems fine. I tested the new fuel injectors by removing them and connecting them to the fuel rail and cranking the engine. they all work fine and do not leak after shutdown. I'm thinking of replacing the head. Is it possible that the gas could get by a stuck valve? Any ideas would help. I really dont want to spend $500 on something that will not make a difference but, Im out of ideas.
Assuming you let the injectors sit in a manner you could visibly see they are not leaking, you can eliminate that one Id say. That leaves the regulator diaphragm being questionable. If that was bad the fuel would go into the vac line and into the intake eventually. So if you ran it, shut it down, pulled the vac line off the regulator, and say put something to catch any fuel that ran past a ruptured diaphragm, you could test that part system. Personally I can see how a stuck or burnt valve would cause this one, and the fact you've done a compression test eliminates that with the even compression.
Thinking out loud here, even if somebody really screwed up the vent lines from the fuel tank, the only thing I can even remotely think of is, a very full topped off tank, a gas cap that we know is not vented so any pressure building from shaking around or the hot sun will push raw fuel out that vent line pushing that fuel into the engine. But again, into the intake, where once its fired up it should be flooded on a couple or all of the cylinders till it clears out the extra fuel. That's a stretch, but I see crap done to vehicles nobody would believe.
Like LuckyMac suggested send a sample to Blackstone labs for testing and see what they come back with. This could be the stumper of the year from the jeep gods:worthy:
 

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If it's gaining oil and it's not turning into chocolate milk I don't see how it could be anything other than gas....

Any chance you have a loud muffler and a neighbor who is sneaking over and dumping gas in the oil hoping to stop the noise?
 

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Had the same issue, from what I found in the forums the fuel pump, ccv valve, fuel pressure regulator or leaky injector could be the cause. Luckily my issue was the previous owner leaving the inside of the sparkplug boot on the sparkplug lol
4485078
 
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