Gas in the oil?

[Deluxedave]

Just bought an '86 Bronco II 2.9, automatic. It starts but runs really weak. Lots of leakage at valve covers and the one spark plug I pulled was jet black with powdery carbon deposits. There does not appear to be any evidence of water in the oil, but it is over the fill line and smells like gas. I will be looking into the spark system, but wanted advice on the gas smelling oil. Has anyone ever experienced gas in the oil? The engine is filthy and full of sludge, so any suggestions there would be appreciated as well.

Update: The gas in the oil appears to have been related to a bad computer that caused the previous owner to ground the fuel pump thru the test plug in order to make it run. I have since replaced the computer and the fuel pump runs for the 2 second prime and then shuts off until you start it. I have not yet done a fuel pressure test.

 

[IMenriched]

Just bought an '86 Bronco II 2.9, automatic. It starts but runs really weak. Lots of leakage at valve covers and the one spark plug I pulled was jet black with powdery carbon deposits. There does not appear to be any evidence of water in the oil, but it is over the fill line and smells like gas. I will be looking into the spark system, but wanted advice on the gas smelling oil. Has anyone ever experienced gas in the oil? The engine is filthy and full of sludge, so any suggestions there would be appreciated as well.

MOst Likely...you have a bad FPR (Fuel Pressure Regulator). a very bad one

if you pull the little vacuum line off the FPR ...willing to bet that gas will dribble out of it....IF yes , then the FPR is shot...you'll need a new one.

You'll also need to change your oil and filter. gas in the oil will GREATLY reduce the lubricating qualities of the oil. best not to drive this untill it gets repaired

 

[BlackBII]

Well, at least all the gas might breakdown some of the sludge.

Yeah, most likely the FPR is leaking. Easy to replace. Make sure they give you new o rings, so she dont leak.

 

[jhammel85]

I agree with everyone here. I'd check out that FPR

 

[Deluxedave]

I will check the FPR tonight. Priced them at a little over $100 - seems high for a little guy.....

 

[BlackBII]

Cheapest one is ~30$ from www.rockauto.com

 

[Deluxedave]

Thanks!

 

[Frank The Tank]

I've got a brand new regulator on my 2.9....... turns out the heads were cracked, lol.

4.0 time. I guess i will part out that little dude soon.

Frank

 

[Deluxedave]

OK, I pulled the vacuum line and it was dry. As far as I know, the vehicle has only run about 2 minutes in the last month, but I would have expected to see some fuel there if it was bad. Is there another way to check without a vacuum pump?
Are there other possibilities for the gas in the oil? Could it be a head gasket or the head itself?

 

[Big Jim M]

Oil after sitting in an engine can get all sorts of smells. One that is looking for a problem and not finding anything except perhaps a smell he doesn't recognize might tend to stop looking elsewhere..
Remember gasoline and motoroil are essentially the same thing. An engine that is filthy and full of sludge may smell more than a clean engine..
I'm saying I'd be looking elsewhere and I'd stop thinking about the smell. As for the oil being over the full mark...Was it YOU that put that oil in there? If not then perhaps it has been over the mark since it was last filled.
Big JIm

 

[kimcrwbr1]

I would change the oil filter and drain a little oil out then add some oil treatment then get it good and warm then do a complete oil change. I am sure the filter in there is full of crap so use a good one to flush it out before you change the oil. see if the smell goes away. could it be leaking through the injectors dumping oil in the cylinders when not running. maybe hook a fuel pressure guage on it and see how fast the pressure drops after it is turned off.

 

[Deluxedave]

I did change the oil and filter already. The oil ran like water even though the vehicle was cold and the gas smell was overwhelming. My intention is to try to get it running better (new cap, rotor, plugs), then change the oil again after it warms up.
Is it reasonable to think that very weak ignition could cause gas in the oil?

 

[Big Jim M]

Nope! Nope! Nope!!

I did change the oil and filter already. The oil ran like water even though the vehicle was cold and the gas smell was overwhelming. My intention is to try to get it running better (new cap, rotor, plugs), then change the oil again after it warms up.
Is it reasonable to think that very weak ignition could cause gas in the oil?

Not if it is running at all.. If it is just cranking over and over..well maybe. But if it is running, no matter how badly, the fuel should all be consumed.

When cold the oil gets to it's thinnest weight possible. If you have 10W 30 in there it should be 10W when cold.
Or you sure the gas smell is in the oil and not from a small external leak?
Big JIm

 

[Deluxedave]

It sure seemed like it was in the oil. I will get her runnin' again and redrain the oil, recheck the FPR. I will also post any additional info then.

 

[Deluxedave]

I put on a new cap and rotor and new plugs and started it. It ran really rough, but did idle without help. It sounds like there is an exhaust leak on the driver's side of the engine compartment, but no smoke in the engine compartment. The tailpipe spews thick gray exhaust that has black carbon flecks when I hold a paper towel there. No air bubbles in the radiator with cap off and no gas in the vacuum line for the FPR. I have a working coil that I was thinking of swapping out to see if it makes a difference.