drjewalton

I own a 84 z28 305 H.O. and I need help identifying a part located on the driver's side firewall. I have attached a picture with an arrow pointing to what I'm talking about.

What is this? What's it's function? Why does mine look like it's caved in? Does it have to do with vacuum?

I am asking this because I have had a few minor problems that I cannot figure out:

1. Lots of interior "pressure noise" when I adjust anything on the heater/ac controls

2. Check engine light ONLY while cruising at 60-75 mph...disappears once I get back to city driving (checked and got ECM code 44 - lean mixture condition)

3. No washer pump functioning for windshield wipers.

Any takers? All help is appreciated

nickhil2003

i see theres 2 lines running from it, were do they go?

drjewalton

To be honest, not sure because I'm not near the car tonight....stored at my dad's garage...i will have to get back to you on that.

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iTrader: (14)

looks like a piece of rubber/foam just pushed in there. Might be nothing.

djmarch

iTrader: (4)

Need a closer pic...

drjewalton

I will get a closer, more detailed picture and post soon

drjewalton

Here are some more pics...again, what is this and what's it's function? The larger hose coming from the bottom leads to a port on the back of the intake manifold...the smaller cable above it leads across the firewall and back behind the condenser and blower motor. Please reread original post regarding small problems I am experiencing...does this have anything to do with them? Thanks again.

jharrison5

Looks like some kind of EVAP canister, but I have never seen anything like that before.

Diabloformula

I say disconnect it and plug the hose going to the manifold and see what happens then.

sonjaab

My 84 ho has the same thing! Will try and climb over the snowbank and
get into the barn and eyeball exactly what/where its for!
Its sleepin' for the winter.....................

drjewalton

C'mon...surely someone out there knows what this is! I have searched images,diagrams, schematics online and cannot get any answer as to what this is and what it does, although it is present on a lot of 3rd gen engine compartment images online. I have also paged through the Haynes manual as well as the Chilton's manual with no luck.

Does anyone have a gm shop manual and could look it up? Any help will be much appreciated.
I don't want to really mess with it until I know what it is and what it does.

[It's location is just above the master cylinder and brake booster on the firewall...as mentioned before, the larger hose on the bottom leads to a port on the back of the intake manifold (vacuum?) and the smaller cable above the hose channels across the firewall to the passengers side and goes behind the a/c accumulator unit. It's usually not caved in either! Don't know why mine is....nothing touches it when the hood closes]

n1ffer

I believe it is a vacuum canister.

regal301

vacuum canister for the heater/ac controls.

later cars have a round one hidden under the fender near the nose.

if yours is leaking it can be bypassed by connecting the lines together.

drjewalton

In reviewing my first post, could a leak be causing my problems listed? Also, why would it be caved in?

regal301

the pressure noise at the heater control is a vacuum leak in the heater control.

the lean condition is most likely a vacuum leak,most likely a combination of the heater control,canister and a few hoses.

the washer pump is unrelated and most likely a bad pump,or hose.

the canister is a storage device for negative pressure,my guess is the plastic just gave out in the heat of the engine compartment.

drjewalton

Thanks for the help regal301. Obviously, I'm new to being a camaro owner and I lucked into the Z28 that I own.

It's all original (pretty mint cond.) with only 27800 miles and I didn't want to mess with anything until I had an idea of what it was.