Fuel in My oil pan

[ryan.johnson]

Friday night I tried to take old rusty out and the truck wouldn't run once off choke. I called it for the night and got back to it today where it still wouldn't run, pulled my dipstick and my oil level is way too high, also smells like gasoline.

I have a 1406 eddie on a mild 350, mechanical fuel pump. The fuel pump was replaced around 2000 miles ago this year and the same with the carb. The carb also has off road needles and seats.

I check my oil level ever other fuel fill up because it burns a little oil, so this had to have happened the last time i drove.

anyone have any ideas? is my fuel pump somehow leaking into the block? Fuel spilling over the carb bowls would be a slow thing wouldn't it?

Since I replaced the carb I've had an off idle stumble on hot days, but other than that the truck has been perfect.

thanks for any advice in advance.

-Ryan

 

[texnet]

Sounds to me like the fuel pump is leaking internally. The most likely cause is a hole in the diaphragm.

 

[rich weyand]

Once you replace the fuel pump, check the vacuum advance connection. I bet you have it connected to the passenger side vacuum port on the carb, i.e. ported vacuum. Unless you are running a full emissions kit, that's incorrect. It should be connected to the drivers side vacuum port, i.e. manifold vacuum. That should cure the off-idle stumble.

 

[ryan.johnson]

wont running it on manifold vacuum cause it to be advancing at idle? I've always been told to run ported, will see if that works. Thanks

 

[MadOgre]

I would think the carb is spilling fuel down the intake when not running. These eddy carbs are really finicky when it comes to fuel pressure. A fuel regulator is pretty much a must if you want trouble free operation from your carb. So either you have pushed your floats up with to much pressure, or you are having heat soak problems. I would venture to say its a float issue. I saw a guy on you tube put a brand new carb on a motor and all it did was dump fuel down the intake. To much pressure. I'm betting that is what you got going on because you would need a significant amount of fuel to raise your oil level to the point you notice it.

 

[rich weyand]

wont running it on manifold vacuum cause it to be advancing at idle? I've always been told to run ported, will see if that works. Thanks

Yep, running it on manifold vacuum will cause it to be advanced at idle, as it should be. Low pressure charges (i.e. at high vacuum, like at idle) burn slower, so need the spark to kick them off earlier. That is the whole point of vacuum advance, starting in 1930. Ported vacuum began in 1968, the point being to delay the spark long enough at idle that the charge was still burning when it was dumped, which, together with the air pump, causes burning of unburned hydrocarbons in the manifold. It also caused exhaust valves and runners to run hotter, engines to run hotter, use more fuel at idle, and have off-idle hesitation. But, hey, it reduced pollution at idle, which, if you have a lot of cars stuck in traffic jams in LA, helps reduce pollution. For the rest of us, not so much.

 

[rich weyand]

I would think the carb is spilling fuel down the intake when not running. These eddy carbs are really finicky when it comes to fuel pressure. A fuel regulator is pretty much a must if you want trouble free operation from your carb. So either you have pushed your floats up with to much pressure, or you are having heat soak problems. I would venture to say its a float issue. I saw a guy on you tube put a brand new carb on a motor and all it did was dump fuel down the intake. To much pressure. I'm betting that is what you got going on because you would need a significant amount of fuel to raise your oil level to the point you notice it.

Yeah, could go either way: leaking fuel pump, especially if the fuel pump is original or at least old; or fuel pressure overpowering the float valves, especially if the fuel pump is new or recent. Eddys don't like too much fuel pressure, though I am running a new fuel pump and have no problems.

On second thought, I would think that the Eddy blowing fuel would just cause it to run richer than a cob, and not get into the oil system.

 

[MadOgre]

The only way to get fuel in the oil is to have fuel enter the intake when the engine is off.
Maybe the fuel pump although I have never seen or even heard of that happening. It is my understanding that they are designed to fail so that they loose pumping ability not leak fuel into the crankcase.

Extremely high fuel tank pressure could possibly cause a fuel pump to leak into the crankcase ? I dunno.

 

[ryan.johnson]

Drained the oil and installed a new pump today. Yesterday when I checked the dipstick it was 6 inches or so past the full mark and smelt of gas, when I measured the oil from the change today I only got a little more than a gallon of oil out of drain pan. Completely lost on this one.

Tomorrow I'm going to cut the old pump apart and look at the diaphragm, cause I'm at a loss. I really doubt all the gas evaporated in the hour or so that it sat in an open pan, but at this point I'm really confused.

any ideas?

Also I run a holley fuel regulator to my carb at around 4 psi, could this have put too much back pressure on the pump and killed it?

any insight is appreciated.

 

[kleedus]

I had my jimmy overflow the carb and completely fill a 454.

the jimmy was a diesel and had no vent in the tank the heat of the day pressurized the tank. and in 3 hours the 454 was full of gas hydro locked the motor and bent 2 rods.
I changed the sending unit to a gas one with a vent

make sure your tank vent is working right

 

[Driver4r]

We arnt gonna start this again.........

Timed vacume is the performance way. Manifold is poor man's throttle response XD.

 

[yeol1]

I had the same issue with mine. It was my fuel pump not working properly.

 

[rich weyand]

We arnt gonna start this again.........

Timed vacume is the performance way. Manifold is poor man's throttle response XD.

And from the introduction of vacuum advance in 1930 to 1968, every research department at every automobile manufacturer was too stupid to realize it, and just kept using manifold vacuum. It was only when federal pollution mandates came along in 1968 that the scales fell from their eyes and they realized they had been doing it wrong all along.

Seriously, at car shows (and in Indiana there are a lot of them), I scan engine compartments for which way they are hooked up. It's about 4 out of 5 that are on manifold vacuum. I suggest to the 1 out of 5 on ported vacuum that they try the switch and see what they get. All have reported better performance on manifold vacuum: better idle, better throttle response, less hesitation.

Best recommendation is probably to try it both ways and see what you get.

 

[Driver4r]

And from the introduction of vacuum advance in 1930 to 1968, every research department at every automobile manufacturer was too stupid to realize it, and just kept using manifold vacuum. It was only when federal pollution mandates came along in 1968 that the scales fell from their eyes and they realized they had been doing it wrong all along.

Seriously, at car shows (and in Indiana there are a lot of them), I scan engine compartments for which way they are hooked up. It's about 4 out of 5 that are on manifold vacuum. I suggest to the 1 out of 5 on ported vacuum that they try the switch and see what they get. All have reported better performance on manifold vacuum: better idle, better throttle response, less hesitation.

Best recommendation is probably to try it both ways and see what you get.

Here we go again.......

 

[ryan.johnson]

took the old fuel pump apart today, diaphragm is in one piece. So either way at this point the fuel pump isn't the problem. I don't want to ruin an oil change if the fuel pump wasn't the problem.

Diagnostically what else can I check before I fire it back up?