Scratchin my bald-ass head here.

[cbxer55]

So, I read anarticle on my phone on MAF testing. Stated if you pull the plug while warm and idling, the engine should die. DId that today, pulled plug on warm idling engine. NO CHANGE. Nothing. Sat there purring like a kitten. Hmmmm.....

Read another saying if you remove the oil filler cap while idling and place a napkin over the opening, it should try and suck the napkin in. Or puff it out if the PCV system is plugged. Once again, BIG NOTHING. Didn't suck it in, didn't puff it out. NOTHING. So, I had a threaded crankcase breather on my grudge shelf. Put it on, revved the engine, VROOM, just like always.

Drove it to work after doing both of the above. Perfectly fine, Filled the tank at the half mark yesterday, checked mileage. 20.55 mpg. On a 3.0 Ranger with 4.10 gears.

What gives here? How is my truck even running. The o2 sensors are 28 years old and have 209,000 miles on them. I'm certain they are bad, but it still runs just perfectly fine. 20.55 mpg on a 3.0 Ranger is actually outstanding.

Is my truick haunted?

 

[Li'l Work Truck]

 

[SenorNoob]

Sounds like you just got the one that was built for the quality department to inspect. LOL

I'd bet that's actually more common than the group here would lead you to believe. Lots of people get here because they had a problem.

 

[pentode]

I was just typing "sounds like you have a healthy truck" when the above came in.

I don't actually know the fueling strategy on the 3.0 computer but I would guess it knows it's running from either the cam and or crank sensor and just defaults to a safe value if the maf signal is lost. I would think it would throw a code pretty soon though.

I also wouldn't expect much pressure or vacuum under the valve cover if the valve guides and valves are healthy (and rings too I suppose)

My 3.0 has 240k on it and AFAIK has the original O2 sensors and they work just fine. And I would guess yours are too if you're getting 20 mpg.

The 3.0 gets no love but it's a great little gutless motor.

 

[alwaysFlOoReD]

I've been thoroughly impressed with my 3.0 in my 2011 Escape. About 200,000 miles on it. There is a check engine light to do with an emissions component but that hasnt affected the drivability much.

 

[Curious Hound]

It's a 3.0l. They're great.

 

[cbxer55]

I've been thoroughly impressed with my 3.0 in my 2011 Escape. About 200,000 miles on it. There is a check engine light to do with an emissions component but that hasnt affected the drivability much.

The CEL in mine burned out in 2019. It had been on for over 10 years. When I hook a code scanner to it, there are a slew of codes. Too damn many, and the monitors are a mess. But it runs and runs like the Everready Bunny.

 

[PetroleumJunkie412]

Ur bald?

 

[cbxer55]

I was just typing "sounds like you have a healthy truck" when the above came in.

I don't actually know the fueling strategy on the 3.0 computer but I would guess it knows it's running from either the cam and or crank sensor and just defaults to a safe value if the maf signal is lost. I would think it would throw a code pretty soon though.

I also wouldn't expect much pressure or vacuum under the valve cover if the valve guides and valves are healthy (and rings too I suppose)

My 3.0 has 240k on it and AFAIK has the original O2 sensors and they work just fine. And I would guess yours are too if you're getting 20 mpg

If the PCV system is working, removing the oil cap is a giant vacuum leak. So, when I removed it and the engine kept purring along, I assume it means the PCV valve may be plugged up. Possibly from the four years my sister had it and didn't change the oil for over 42,000 miles. Since removing the cap doesn't seem to bother it, I am just going to run it with the crankcase breather I put on it today. Worse that can happen is it smells like an old school hotrod, oil vapor smell everywhere I go. Been there done that. LMAO!!

 

[cbxer55]

Ur bald?

Not really. I am 64, soon to be 65. I keep it cut very short so I don't get helmet hair when riding one of my three motorcycles.

 

[pjtoledo]

the hose from the intake tube to the valve cover is already supplying air to the crankcase.

 

[cbxer55]

the hose from the intake tube to the valve cover is already supplying air to the crankcase.

I know this. But the PCV valve on the driver's side valve cover is sucking the air out of the crankcase and feeding it to the intake behind the TB. Hence, if you remove the oil filler cap while running, the hose from the intake is short circuited and it's pulling in unmetered air through the filler hole. Hence large vacuum leak. But my truck doesn't seem to care about it. So the PCV valve must be plugged up with glop.

 

[pentode]

PCV valve should be mostly closed at idle, which is why I wouldn't expect removing the oil filler cap to cause major issues. If the PCV were stuck open, it probably would. This is also why I wouldnt expect much suction at idle with the cap removed. Not like it would be sucking in a rag or anything.

As pjtoledo mentioned, the crankcase basically has free access to outside air, so the vacuum leak caused by the pcv needs to be controlled by the valve anyway. Not trying to be argumentative, if there's something I don't understand about PCV valves I'm always happy to learn.

 

[cbxer55]

PCV valve should be mostly closed at idle, which is why I wouldn't expect removing the oil filler cap to cause major issues. If the PCV were stuck open, it probably would. This is also why I wouldnt expect much suction at idle with the cap removed. Not like it would be sucking in a rag or anything.

Vacuum is highest at idle, and lowest with your foot on the floor. The PCV valve is connected to the intake under and behind the TB. Soat idle, it should be sucking the hardest. Try it sometime. With the engine idling, disconnect the fresh air hose from the intake to the valve cover. Or just take off the oil filler cap. Engine will run real bad, missing, not taking throttle well. Been down this road with many other vehicles over the years. But, as I said, if the PCV valve is plugged, and it likely is, I am not going to lose any sleep over it. With the 3.0, it's under the upper intake manifold. Need to remove that to fix it. Not going to bother. Drove it to work today with a breather on the oil filler hole. Ran FINE!! Years ago I tried running that breather and couldn't, due to it running like crap.

 

[Curious Hound]

I've never noticed a difference with oil filler cap removed on any of my vehicles.