What is this mystery box? 94 4.0L

94firstranger · Oct 6, 2018

All,

I am not a car person (but trying to be one). While digging under the hood of my 94 Ranger 4.0L 4x4, I saw this box between the battery and the radiator (on driver's side) and a disconnected line. Looks like the rubber elbow is rotted. I followed the line and it appears to connect around the throttle body area.

No telling how long it's been like this. I've attached a top-down pic of the box. Looks like there are large ports on top as well.

What is this box? What purpose does the disconnected line server?
Thanks!

adsm08 · Oct 6, 2018

Vapor canister. It stores fuel that would otherwise have evaporated.

RonD · Oct 6, 2018

Yes, EVAP system charcoal canister

Connector is called a SPOUT connector, it "was" used to set Base Spark timing for electronic distributors, it could now be used to diagnose ICM(ignition control module) and/or computer Spark advance issues.
If disconnected engine will start and run but would have no computer assist with spark advance, so run sluggish and hestitate

94firstranger · Oct 6, 2018

Thank you both. I appreciate it. My engine doesn't seem to hestitate but it does feel like it ever so slightly surges when idling. I may connect this back up and see if it resolves things.

A google search also indicates there are caps that go on the two ports on top. No idea where those went so I'll try to buy some more.

EDIT: Can someone post a link of where I can buy a new spout connector? Looking around a few sites and not seeing much. Thanks!

adsm08 · Oct 6, 2018

94firstranger said:
Thank you both. I appreciate it. My engine doesn't seem to hestitate but it does feel like it ever so slightly surges when idling. I may connect this back up and see if it resolves things.

I think you misunderstand. The plug you pictured is not disconnected. The little grey slug in the connector is a jumper that connects the two wires to each other. If you remove it you will disable the computer's ability to command spark advance.

A google search also indicates there are caps that go on the two ports on top. No idea where those went so I'll try to buy some more.

Not all of them had caps.

94firstranger · Oct 6, 2018

adsm08 said:
I think you misunderstand. The plug you pictured is not disconnected. The little grey slug in the connector is a jumper that connects the two wires to each other. If you remove it you will disable the computer's ability to command spark advance.

Not all of them had caps.

Ah, I see. What I was referring to was the hose that's unplugged from the box:

Bgunner · Oct 7, 2018

That box is the charcoal canister. The hose that is disconnected is either the intake into the canister or output to the intake manifold. This box is for emissions and is operated by a solenoid to burn gas fumes from the tank.

To tell which line it is follow the line to see if it goes to the intake manifold/solenoid, if so then it is the output side of the canister.

94firstranger · Oct 13, 2018

Thank you all for the help. I'm new to working on my truck (or any car). I replaced the rotted hose elbow and hooked it back up without any issues.

Would the idle of the truck be impacted if this was not connected? It seems like the idle was better after I connected it but that could be placebo effect or something.

Thanks!

What is this mystery box? 94 4.0L

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