Zero oil pressure - 4/23/24 update - oil changed and seems to be working fine

[Steve83]

Turning the pump backwards just makes a sloshing sound in the oil pan.

That suggests there's NOT some obstruction plugging the pickup tube, which was the point of the test.

(click this text)

 

[thegreatjustino]

After further diagnosis today, oil pumps out of the engine, through the hose to the remote oil filter, through the filter, and back into the engine.

The oil that I pumped into a container from the hoses to see if there was any flow, looks like chocolate milk and smells like gas, so fuel is somehow getting into the oiling system. I've heard of this happening, but don't know what causes it. Is this now a fuel pump problem or something else?

The engine was rebuilt during the build of this Bronco a decade ago, and likely has less than 6,000 miles on it.

 

[DirtDonk]

It's usually the fuel pump diaphragm leaking into the engine instead of out of the weep hole. Happens quite often as a matter of fact.
It might not be the only way to get gas in there, but it's probably the most common way.
And as you know, fuel pumps don't like to sit... At least not once they've been used. Seem to be fine sitting on the shelf, but put some gas and a couple of hours on them, and then let them sit for a month or three, and voila! Failed fuel pump.

Worth a look-see at any rate.

Paul

 

[thegreatjustino]

Worth a look-see at any rate.

How do you determine if the fuel pump diaphragm is leaking? Or is this just a replace the part and see type situation?

 

[DirtDonk]

Not sure. There’s probably a way to test it, but it sounds like it would be a serious case of mocking it up external to the engine, in order to actually see it in action.

 

[Broncobowsher]

You can also get that fuel/oil/milky from short runs and not getting the engine fully warmed up. Fully as in the oil up to temp, not just the water. That is a lot of short drives, moving in/out of the garage, idle time. Not actually getting it out onto the highway and cruising for an hour.

Fuel from the cold start gets past the rings, moisture from combustion gets past the rings, but never sees the heat needed to drive the contaminates out.

 

[Torkman66]

Gas in oil is very odd. Does not easily happen. Can be pump diaphragm as mentioned or in some very odd combination failures can actually get through rings or head gasket, but in those cases engine rarely will run. So I’m guessing pump. If it is the pump I’d think it wouldn’t start. If it starts and is pumping fuel into oil at cam lobe, you can definitely get enough fuel in oil that it is too thin for oil pressure to build.
I would buy a cheap pump at parts store, drain oil, replace filter, and see what you get. If that gets you oil pressure back and it runs, drain oil again and replace filter again and all the fuel should be out of oil galley. Geez, I hope this is it. That would be an easy solution.

 

[thegreatjustino]

I would buy a cheap pump at parts store, drain oil, replace filter, and see what you get.

A replacement Carter pump should be here from Rock Auto today. There's an Autozone within walking distance of my house. I will go pick up new oil and filter in the next couple of days. Will know if the new pump fixes the issue by this weekend.

 

[fordguy]

To add a little more info here, due to the custom nature of this build, this does have a remote oil filter kit installed. So one more thing that could be causing problems or malfunctioning.

I had a 460 with remote and had to remove it to get oil pressure reading where I could live with it. I di not build the engine or the truck, bought it that way.

 

[thegreatjustino]

I had a 460 with remote and had to remove it to get oil pressure reading where I could live with it. I did not build the engine or the truck, bought it that way.

In the seven or eight years I've owned this Bronco, there's never been an oil pressure issue until this month. At this point the remote kit doesn't seem to be causing any part of the issue. Like you, I bought the Bronco with the remote kit installed - I bought it from the guy who built the Bronco. If by some chance it does end up being part of the issue, I'll need to find a remote setup that works since it's physically impossible to install a filter directly on the engine with the custom frame built the way it is.

 

[bronco italiano]

Any smoke from the tailpipe/s?
Mechanical FP 8 years old.. It had a good run if it is in fact the failure point.

 

[fordguy]

In the seven or eight years I've owned this Bronco, there's never been an oil pressure issue until this month. At this point the remote kit doesn't seem to be causing any part of the issue. Like you, I bought the Bronco with the remote kit installed - I bought it from the guy who built the Bronco. If by some chance it does end up being part of the issue, I'll need to find a remote setup that works since it's physically impossible to install a filter directly on the engine with the custom frame built the way it is.

Mine was such that I was able to remove it.

 

[Steve83]

How do you determine if the fuel pump diaphragm is leaking?

There should be a strong odor of gas from the weep hole, even if the gas is flowing past the pump arm into the crankcase. But when you pull the pump off (if the engine has run recently - it doesn't have to run long enough to get hot), you should see if there's gas around the pump arm. If you're sure there's NOT, you can re-seal it to the engine without even disconnecting the lines.

 

[thegreatjustino]

There should be a strong odor of gas from the weep hole, even if the gas is flowing past the pump arm into the crankcase. But when you pull the pump off (if the engine has run recently - it doesn't have to run long enough to get hot), you should see if there's gas around the pump arm. If you're sure there's NOT, you can re-seal it to the engine without even disconnecting the lines.

I've actually read you can hook a brake bleeding vacuum pump up to the fuel pump. If you can't get it to hold vacuum, the diaphragm is toast. Can anyone confirm this test will work? I did read this tip on facebook which we all know is more often than not full of crap...

 

[bronco italiano]

That makes sense Justin. Have you pulled the pump and bench tested it yet? Or did the carter come in and your just gonna install it?

 

[Broncobowsher]

I've actually read you can hook a brake bleeding vacuum pump up to the fuel pump. If you can't get it to hold vacuum, the diaphragm is toast. Can anyone confirm this test will work? I did read this tip on facebook which we all know is more often than not full of crap...

Should work if you cap the inlet and suck on the outlet. Otherwise you will suck through the check valve or be testing the check valve.

 

[Steve83]

I've actually read you can hook a brake bleeding vacuum pump up to the fuel pump. If you can't get it to hold vacuum, the diaphragm is toast.

...or you're still boiling the gas inside by lowering the pressure. Depending how much is inside the pump, it could take a while to vaporize & remove it all. Warming the pump would speed that up, though.

 

[thegreatjustino]

Should work if you cap the inlet and suck on the outlet. Otherwise you will suck through the check valve or be testing the check valve.

Well this test seems to prove it's not the fuel pump. With the inlet plugged and the vacuum pump hooked to the outlet to the carb, the fuel pump holds a steady 25hg of vacuum. This seems to indicate the fuel pump is fine.

Since chocolate milk oil can also come from water in the oil, I checked the cooling system. It's topped off and bright green. Doesn't appear that water is getting into the oil or vice versa.

Curious what else I should be checking here.

 

[Wild horse 75]

The moisture in the oil is probably just from sitting for a year. Fuel too. I’d change the oil and see if you can get oil pressure with new oil and a fresh filter. If you can’t get oil pressure you’re going to be pulling stuff apart to find out why anyway. That’s when you can check other things.

 

[thegreatjustino]

So this is getting more and more bizarre. I had the Bronco towed to a fabrication shop about 40 miles away to have some suspension work done. Turned out to be one of those shops you paid the bill and left with a bad taste in your mouth. They asked me while they had it if I wanted them to change the oil, to which I told them there was no need for them to do so. Turns out they did anyway - the filter was not the filter that was on it when it was dropped off, and had 3/12/24 hand written on the bottom of it, which I'm assuming is the date of installation at their shop. I have no clue what oil they supposedly put in during the oil change, but considering the Bronco wasn't even driven while it was at the shop, I can only assume they're responsible for the contaminated oil. Mind boggling...