Can somebody explain vacuum hoses to me in layman's terms?

[ZappDogg]

I have an '04 Taurus that keeps tripping the engine light for running lean. From my research, it appears that the issue is either the MAF, a bad O2 sensor, or a leaking vacuum hose.

In the beginning of this problem, I could hear a whistle coming from the hose that leads from the air filter to the MAF. If I pressed on the hose, the whistle would go away. That's what led me to think that there might be a leak.

Is that hose actually a vacuum hose, or am I just confused on the terminology?

 

[Demon-Xanth]

A vacuum hose is literally a hose, just instead of a fuel line or a coolant hose it has a vacuum inside of it.

 

[ZappDogg]

So if I do indeed have a vacuum leak, would I need to replace the hose, or something in addition to the hose?

 

[Demon-Xanth]

Originally posted by: ZappDogg
So if I do indeed have a vacuum leak, would I need to replace the hose, or something in addition to the hose?

I had a leak a while back and the end of the hose was cracked, just cut an inch off the hose and stuck it back on. It depends on where the leak is.

 

[StageLeft]

Could be the hose is leaking around where it attaches or it's become degraded with oil and has a hole.

 

[franksta]

I think you may be confused on terminology. The one you are describing sounds like intake duct.

I would call vacuum hoses the ones going to the brake booster or vacuum accumulator. Check them all for cracks and holes.

 

[CrackRabbit]

A vacuum leak before the MAF generally won't cause a lean condition as the MAF can see the airflow and compensate for it. Leaks after the MAF generally trip sensors because the MAF is reporting one thing and the O2 sensors are seeing another.
I had a vacuum leak on my Focus recently, it was on the hose/tube that goes from the PCV valve to the throttle body. Oil had degraded the rubber portions of the hose and caused them to fall apart.
Check all the hoses going to and from the throttle body/ intake manifold for leaks and cracks, that is likely where your problem lies.

Another way to check is while the car is running remove the electrical connection to the MAF. If the car continues to run you have a leak somewhere after the MAF.

 

[ZappDogg]

it looks like there are two small hoses coming off of the hose i described, about the diameter of a nickel. maybe those are vacuum hoses?

i'd go take a picture, but it's sleeting at the moment.

 

[StageLeft]

I had a vacuum leak on my Focus recently, it was on the hose/tube that goes from the PCV valve to the throttle body. Oil had degraded the rubber portions of the hose and caused them to fall apart.

Common problem with my Mazda MPV, too. I replaced this hose recently chasing (unsuccessfully) a problem at low throttle.

 

[bruceb]

Just replace the suspect hose and see if the issue goes away. Hoses are not very expensive and are usually very easy to replace. As mentioned, if it is a vacuum line, it is just standard auto type rubber hose. Get it at any auto parts store. They do dry out with time and will feel loose on the fitting. A good hose will be pliable and fit very snug on the fittings.

 

[ZappDogg]

I know almost nothing about car engines, guys. In this picture, the hose I'm referring to is number 6. Between the throttle body and the MAF. Would that be a vacuum hose?

Would I need to disconnect the battery to take that hose off?

http://www.trademotion.com/schematics/J/JN00160.gif

 

[Demon-Xanth]

That's just an intake tube. Nothing special about it, it's just a tube that's the right shape and length to fit.

 

[ZappDogg]

So are you saying if I had a vacuum leak, it couldn't be that hose?

What about disconnecting the battery?

 

[Demon-Xanth]

Vacuum hoses connect to different points depending on what they're doing. If moving something causes a leak to start/stop, the problem is likely near by. Don't over think the problem. If you can understand how a vacuum cleaner's hose works, that's how vacuum lines work. The engine is one big air pump, connect a tube to the intake and it'll draw a vacuum. Depending on where you connect it (before or after/at the throttle body) varies how much of one and when. You can usually tell where it's at because there will be a loud hissing which is different from the usual belt noise.

 

[CrackRabbit]

Originally posted by: ZappDogg
So are you saying if I had a vacuum leak, it couldn't be that hose?

What about disconnecting the battery?

It is certainly possible for the intake tube to crack or leak, especially if it is made of plastic like most modern cars are.

There should be two ring clamps that hold it on, one at the throttle body one at the air box.
Loosen them and it should pop off easily.

As long as the cables aren't in the way you shouldn't need to do anything with the battery.

Looking at the diagram there is a third ring clamp that holds it to the MAF portion.
Disconnect the wire from the MAF sensor before removing the tube.

Take it off and inspect it for any warping or cracks and then reinstall it and tighten the ring clamps back up.

While it is off you should check any rubber lines going to the throttle body.

 

[LTC8K6]

http://www.tauruscarclub.com/

They will probably be able to help you.

 

[Mattp91]

Hey guys im having trouble understanding the components of a vacuum hose and I wish to know if a brake booster comes attached to a vacuum hose. I would really appreciate it if any one of you could help me with this issue. If you wish to contact ke viw email my email is mposa005@fiu.edu thank you

 

[MovingTarget]

Wow, holy necro thread-bump...2009!

What sort of issue are you having? I think the brake booster does have a vacuum hose connected to it, but then again, since my vehicles are from the 1980s, just about everything does. Tracking down vacuum leaks is a special level of hell for me.