What is this?

[ok89]

Ok well me and my brother are stumped as to what this is?

Anyone know what the thing circled in yellow is?

 

[Alec]

Something with the brakes I think, as those look like brake lines and it's right by the master cylinder.

Damn, it's amazing how much room there is under the hood when you don't have all the $h!t I have!

 

[DocVijay]

Brake lines.

That's where the brake lines start.

 

[Diff Whack Daddy]

That is the ABS motors. It's what controls the pulsing of the front and rear brakes. It's what makes that humming noise when you slam on the brakes and engage the ABS system.

 

[KEbert]

What DiffWhack said. It has to do with the ABS and traction control motor.

 

[ok89]

Ok well I will ask another question.
What is this?

 

[jimmiecakes]

You have 4WABS (4 wheel anti-skid brakes) and this is the controller unit. It contains the actuators, pump and accumulator.

Be extremely careful when working on these - IIRC, the accumulator is pressured to something like 2000/2500 psi with brake fluid.

 

[Diff Whack Daddy]

Okay, now I am stumped.:mattmoon: What is it connected to?

 

[TarHeel085]

well i guess mine doesnt work very well, the other night i smashed my brakes and the wheel slid a little.

 

[jimmiecakes]

What is it connected to?

Wow... now there's a question. OK, the obvious part is the brake lines..... a couple to the master cylinder, probably via the proportioning valve and one to each wheel.

Electrical/electronic connections to the wheel speed sensors, powers and grounds and likely a few places I'm forgetting.

I don't know if you've experienced the "ABS shuffle" before, but this is the gizmo that makes that catrwaulig and makes your foot feel funny in hard braking on iffy surfaces.

As with anything technological, the early ones are crude compared to the latest offerings...... the old learning curve thing (don't forget, you Yanks went to the moon with less computing power than some wristwatches have now).

Your second picture is the EGR valve. It dilutes (NOT "leans out") the intake charge to reduce combustion chamber temps thereby reducing the formation of oxides of nitrogen (NOT nitrous oxide). It's these oxides of nitrogen that react with sunlight and give some cities that brownish "dome". Reducing CC temps (and combustion pressures) also helps to reduce engine ping.

Earlier 4.0Ls did require one as they met EPA guidelines without it. As standards get tougher and technology changes with each passing year, we see the addition/deletion of various components.

 

[ok89]

Wow I'm learning alot here.
I have another one for you:
This time its about the rear liftgate.

What are these?

 

[TarHeel085]

ive always wondered that myself. i think maybe there vents.

 

[Alec]

One is a vent to let the cavity in the door breathe. The other just looks like one so both sides match.

 

[jimmiecakes]

I first encountered these kinds of things (or first noticed them, anyway) when Chevy changed body styles on the pick-up 'bout '88. The size of the doors coupled with improved cabin sealing made it hard to close the doors. In an attempt to reduce the effort used to close the doors, they installed a vent with a rubber "gill" to allow air to escape from the cab into the door cavity (and I would imagine) out through the door drains.

Looking at the amount of air that the rear hatch can move, I'd think this vent is an absolute necessity. I've been in some older hatchbacks where someone closing the deck lid exhuberantly could make your ears pop.

 

[CougarX]

Hey, while we got this thread going what is this:

I know its a switch but since there isn't an underhood light on the 98+'s I don't know what its for. It doesn't set off any kind of dash light if you leave the hood open either so I don't know what it could be for. I've tried to follow the wiring but lose it in the harnesses about a foot from the switch.

 

[ok89]

Try this.
Lock the doors with your key fob with the hood open. Then after you have locked the doors push the switch thing down and let it come back up and the factory "alarm" will go off.

 

[jimmiecakes]

and the factory "alarm" will go off

Yep... not the same kind of switch they use for the remote starts I've seen (boy, ain't that one a POS) and hood lights are controlled by a mercury switch.