Would like some help identifying a component in engine compartment.

[Mataroa]

Hello there!

I bought a (well) used '99 Ranger in Sept. of 2016, and have been replacing parts as I've gone along. Unfortunately, something new has gone awry and it has me stumped.

The truck's been running a bit rough lately. A la, chugging at stops, including rocking of the engine and the whole truck. Got a check engine light on top of that, as though I needed something else to know something was wrong.

The DTC is for a 'lean fuel-to-air mixture' (P0171), and was told it was a fouled MAF sensor. However, I came across something else in the engine compartment that might or might not be related to the issue I'm having. In any case, it's worth knowing what it is and how to fix it.

On the driver side of the engine bay, near the battery and underneath the brake fluid reservoir, is the item in question. To be specific, I can feel air moving out of a hose that comes from the mystery device and runs back towards the engine itself (I haven't pursued the hose the other way, since the issue is out here in the open).

What exactly is this, and what does it do? Even if it doesn't pertain to my DTC, I'd like to fix it. It's going to bug me until I do so.

Images:
Red circle: The leak itself. Can feel air moving through the hose when the engine is running.
Blue circle: The mystery component. I wonder if that electrical connection covered in gunk might have something to do with my problem.

Thanks for reading, any help would be appreciated. As much as I love my truck, I'm sure I'll be visiting this forum quite a bit as stuff breaks.

Edited to add picture, because I only use my head sometimes.

 

[scotts90ranger]

my guess is purge valve for the evaporative emissions, the green cap is for testing the system.

You shouldn't be hearing/feeling air moving around there and that could actually be your problem. That would be known in the automotive world as a "non metered air" leak, that's a reasonably sized hose going straight to the intake manifold... take off that currogated sheathing and see where the hose is broken, if it's broken off find a fuel hose or something that will fit over it and clamp it on both sides, should get it going again.

 

[tomw]

If my interpretation of the picture is correct, the large-ish hose inside the red circle is broken at the bottom, cracked at least. It appears as if it has broken due to old age and the sharp turn it takes. If you replace the hose, you'll likely fix your problem. The hose is allowing air into the engine that the computer doesn't know about, so it is whining that things are 'too lean'... and it can add only so much extre fuel to make up before complaining. Fix the hose and be on your way, if lucky.
tom

 

[Mataroa]

I am pleased to say that after replacing the hose, the truck runs good! Went to a hardware store and cut a replacement hose for a mere $0.39. Immensely better than the solution that Autozone was trying to sell me.

The inner diameter (bore) of the hose required is 3/8ths inches, for future reference.

However, my next question is this: the check engine light is still on. Is a scan tool required to reset the DTC, or will the truck know that everything's better after a certain number of engine cycles (or some other method)?

 

[atikovi]

Disconnect the battery for a minute or buy a cheap scan tool.

 

[scotts90ranger]

disconnecting the battery won't do anything on an OBDII engine so don't bother. After a few warm up cycles it'll go out as it relearns and everything is in check. But you can also buy a $12 OBDII scanner that will connect to your phone or one of the corded scanners should do it too.

 

[modelageek]

Its 2017 and you don't own a $10. scanner. How embarrassing.......... JK, but go get a scanner!

Fyi: I give Elm 327, $15 Autels, etc out as Xmas gifts! People love them.

Sent from my SM-J320V using Tapatalk