Oil has gas smell

[Brambo]

First the specs; 1994 Ford 351 (5.8L) MFI King Cobra. Noticed last year that the oil had a gassy smell, changed the oil this spring & noticed the gas smell & the viscosity was thinner. I have a softball buddy (auto mechanic) who thought it could be the fuel injectors. He came by last night & checked the fuel pressure regulator by taking the top hose off & cycling the fuel pump 4 times, no gas, so that is good. He had no tools as this was after a game, but after looking over my Seloc OMC Repair Manual was confused by the 2 fuel pumps (high & low pressure) & the mostly the Fuel Reservoir / Vapor Separator. As autos do not have this. After reading the manual I realized that the gas is not returned to the gas tank, but is recycled thru the vapor separator?
So now just need to make sure that checking the fuel pressure on the fuel rail is the only step I need to look at. This is to check that an injector is stuck open.
Also have notice that it takes a long time to reach water temps, mainly when the water is cold. Could it be a bad thermostat & running rich & actually put too much gas in, that would get into the oil?
Thanks in advance.

[The Hedgehog]

If your tstat is stuck open, it is probably running in cold start mode. If so, you are running way rich and need to fix that before you wash your cylinder walls.

My guess is that is your problem.

Are you noticing lots of soot on the transom?

[VetteLT193]

this online doc might help: http://www.scribd.com/doc/13072455/Omc-Stern-8698-Final

not sure if there is a mechanical and electric pump combo on your engine but I'd suspect the mechanical pump if there is one.

[mrfixxall]

if the boat is running fine you only need to worry about the electric high pressure pump..they run 2 pumps,mechanical to get the fuel to the high pressure pump because the electric fuel pump used is designed to be in a fuel tank surrounded by fuel so it don't have the capabilities if sucking the fuel that long distance..

Ford fuel pressure regulators are known to rupture the diagrams internally,if theirs a vacuum line pull it while its running and check fuel pressure at the rail...should go to 90 psi,plug it back in if the pressure is still high you need to replace the fuel pressure regulator..

It wouldn't hurt to replace the thermostat,while your at it remove the coolant temp sensor and take a wire brush to it and clean it..They are vary sensitive..

[The Hedgehog]

if the boat is running fine you only need to worry about the electric high pressure pump..they run 2 pumps,mechanical to get the fuel to the high pressure pump because the electric fuel pump used is designed to be in a fuel tank surrounded by fuel so it don't have the capabilities if sucking the fuel that long distance..

Ford fuel pressure regulators are known to rupture the diagrams internally,if theirs a vacuum line pull it while its running and check fuel pressure at the rail...should go to 90 psi,plug it back in if the pressure is still high you need to replace the fuel pressure regulator..

It wouldn't hurt to replace the thermostat,while your at it remove the coolant temp sensor and take a wire brush to it and clean it..They are vary sensitive..

Wow, 90 PSI at the rail.

[mrfixxall]

Wow, 90 PSI at the rail.


yes i have seen engines hydro locked because of a bad fuel pressure regulator,,it forces fuel past the injectors..

[CHACHI]

Change the oil again.

Ken

[The Hedgehog]

yes i have seen engines hydro locked because of a bad fuel pressure regulator,,it forces fuel past the injectors..

Yikes.

That is why I like a fuel pressure guage. Either melt down or (as I just learned) hydrolock.

[BUIZILLA]

it won't run at 90...

the injectors shut down about 65..

[The Hedgehog]

it won't run at 90...

the injectors shut down about 65..

That is what the merc injectors do also. So do my Siemens injectors.

[Brambo]

OK, going to do fuel pressure check & replace T-stat, have looked thru repair manual but can't find the temp sensor location. Any help there??

[Brambo]

Did a Fuel Pressure Test; Start @ 40 PSI, after 3 min @ 38 PSI, after 15 min @ 37 PSI, so that looks good.

So then started motor as per mrfixxall, 35 PSI, pulled vacuum line 42 PSI (had good vacuum on hose), replaced vacuum line back to 35 PSI. Or is the regulator bad?? Should the Ford goto 90 PSI?

So I am going to replace T-stat & watch (smell) the oil this summer:crossfing:.

Still looking for the temp sensor.....

[BUIZILLA]

Did a Fuel Pressure Test; Start @ 40 PSI, after 3 min @ 38 PSI, after 15 min @ 37 PSI, so that looks good.

So then started motor as per mrfixxall, 35 PSI, pulled vacuum line 42 PSI (had good vacuum on hose), replaced vacuum line back to 35 PSI. Or is the regulator bad?? regulator is perfect, numbers are dead on
Should the Ford go to 90 PSI? absolutely not

[mrfixxall]

They only go to 90 psi if the regulator sticks internally,,which completely stops fuel flow at the regulator and does not let it bypass..If this happens then it will force the fuel past the injectors weather its running or not..just a diagnostic tip! :) likr buiz said its working properly..

Another tip,for some reason i have replaced 2, 5.8 and 5.0 omc ford engines,check compression on cylinder #4..That cylinder has a tendency of pealing the ring lands off the piston...star board side rear cylinder..

i have seen in alot on trucks to because of the pcv picks on that cylinder and get all gunked up with oil..