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-   -   Fuel in oil. (http://www.jeepforum.com/forum/f12/fuel-oil-1140825/)

Skari 12-13-2010 11:53 PM

Fuel in oil.
 
First off, thanks to everyone for all the great write-ups and problems I've solved thanks to this site. This is my first post because I've always been able to find my solution just by searching these forums.

So a couple of months ago when it started to turn cold here in Utah I put a Mr. Gasket fuel pressure regulator on my 4.2 w/ a Weber 38 w/ about 8,000-10,000 miles on a rebuild and when I checked my oil about 3-4 weeks later I noticed that it smelled of gas and had a tan/gray foam on the dipstick. So I got on here and searched and figured it was my fuel pump. Thought that maybe the extra back pressure from the FPR had blown out the diaphragm and it was getting into my crankcase that way(?). Kinda pissed me off because I had maybe 100 miles on that oil change, but oh well. So I replaced it with a new (not reman) one from O'Rielly and thought all was good.

So today I check my oil (have put maybe 50-75 miles on it since I changed the pump and oil/filter) and again it smells of gas along with the tan/gray foam on the dipstick.

First thing I think is fuel pump again but it's brand new, not a reman, and I haven't been able to find any other posts where people installed FPR's and had problems blowing out their fuel pumps diaphragm. Maybe I just didn't search for the right parameters, dunno.

Second thing I thought of was the fact that it runs like s*** when cold. It starts up just fine (pump the gas twice, crank it, and it starts up in less than a second usually) but it misses at idle (if I let it stay on fast idle it does ok with a slight miss here and there, but if I kick it off fast idle it drops to about 500 rpms (set at 800-850), misses a bunch, and has a hard time staying started) and nearly dies every time I start to accelerate. So maybe the unburned fuel is getting around the rings and getting into the crankcase? Would it be enough that I could smell it on my dipstick after so few miles?

Any help would be greatly appreciated. Don't dare to drive it much with gas leaking into my crankcase and diluting my oil.

MLJeeper 12-14-2010 05:31 AM

What PSI is the FPR yielding?

Skari 12-14-2010 07:25 AM

Well I have it set to the suggested 3.5, but don't have a tester to test it. I could probably scrounge one up if needed...

vadslram 12-14-2010 08:52 AM

Do you still have a fuel return? Kinda silly question but if you don't have a way for the pumps excess delivery to go away you could be over pressurizing the pump itself.
My bad for not reading you config before I replied but. My stock filter has a bypass built in it and the FPR is inline after that.

Skari 12-14-2010 10:46 PM

Yes my filter has the return line, but come to think of it I don't think all the vacuum lines are hooked up on the evap canister. Could that have an effect on the excess pressure not being returned through the return line? Maybe the line is clogged?

Should I avoid driving it completely with fuel leaking into the crankcase? I need to get to work for the next 3 days before I'll really have a chance to fix it. Work is only 2.2 miles each way, but I mistakingly bought 5W30 instead of 10W30 so the oil was already thin to begin with...

pasinbuy 12-14-2010 11:10 PM

How many miles on your motor, have you done a compression check? Do you blow any smoke or have you in the past? If not and the motor is ok another thing to check is your carb float may be leaking gas.

Skari 12-14-2010 11:16 PM

Less than 10k since a professional rebuild, although the rebuild was about 6 years ago. No smoke but the exhaust does smell rich (or maybe that's just how old carbureted vehicles exhaust smells?). How can I tell if my float is leaking?

vadslram 12-15-2010 04:12 AM

You can drive it with fuel thinned oil but it will take some of the life out of it. Your not pouring it in there and short trips won't get the engine hot enough to flash over. It's a pretty severe way of doing it but now your cleaning up your crankcase. I'd expect to see more leaks, more blow by, a gunky plugged oil filter and a better running engine when your done

pasinbuy 12-15-2010 11:18 AM

Quote:

Originally Posted by Skari (Post 10622881)
Less than 10k since a professional rebuild, although the rebuild was about 6 years ago. No smoke but the exhaust does smell rich (or maybe that's just how old carbureted vehicles exhaust smells?). How can I tell if my float is leaking?


Yes, with gas in your oil you should not drive your Yj.

First do a quick compression check to eliminate a bad ring.

Then check that all plugs are firing. A non firing plug does not allow raw fuel to burn away. Does she idle rough? By pulling each plug and looking or pulling each plug to see if she changes idle. A plug pulled that does not change the idle may not be firing.

To see if a float is leaking, look down your carb throat to see if it is wet. I would try after a short drive to take off the filter, then open the carb using a small clamp to hold open the throat. Come back in five minutes and see if it is wet. Use a flash light to look in. You may see a bunch of gas in the intake.

My money would be on the carb is bad.

Fix your problem or you will find that your rebuild was a waste of money.

Mywrangler94 12-15-2010 06:39 PM

I'll go with passin.....don't drive it. Get it fixed. The gasoline will break down the oil, IMMEDIATELY, and you'll be rebuilding again....mark my words...physics don't change in your crankcase....hope it works out...

uhohthe50 05-31-2012 01:22 PM

I'm resurrecting this old thread since I am currently having the same problem.

Skari, did you ever figure out what was causing the fuel to get in your oil?

Jstout724 05-31-2012 01:57 PM

I have a 2.5l TBI, but For me It was a leaking injector.Does yours have a rail? I would pull your rail off and put them in bottles and see if they are leaking. In my case I pulled out my single injector, because it was 200 bones, and amazingly enough there was a small piece of debri stuck in mine making it leak. Problem fixed, did 3 oil changes in a week because when i did the oil was super thin, wreaked of gas, it was blacker then black. I would suggest you do a couple changes to flush out your crankcase afterwords. I imagine mine is sparkling clean inside lol :D

uhohthe50 05-31-2012 06:39 PM

Quote:

Originally Posted by Jstout724 (Post 13651572)
I have a 2.5l TBI, but For me It was a leaking injector.Does yours have a rail? I would pull your rail off and put them in bottles and see if they are leaking. In my case I pulled out my single injector, because it was 200 bones, and amazingly enough there was a small piece of debri stuck in mine making it leak. Problem fixed, did 3 oil changes in a week because when i did the oil was super thin, wreaked of gas, it was blacker then black. I would suggest you do a couple changes to flush out your crankcase afterwords. I imagine mine is sparkling clean inside lol :D

No I don't have a rail since my is carb'd and not fuel injected :(

pasinbuy 06-02-2012 11:12 AM

First thing is check that float is not leaking. Just rebuild the carb.

Then check that all cylinders are firing. Pull one plug wire at a time. If one of them does not make a change in the idle. It is not firing.


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