SC airbox question?

[Guvnor]

Hi Guys,

I was replacing my air filter last night when I noticed this hose fitting (circled below), on the driver side of the airbox after the filter, that has no hose connected to it. I could not find any hose near by that had fallen off and it seems that unfiltered air can get through here.

I did some searching on here and in my Bentley with no luck. Anyone know that this is for? The PO did a cruise control delete and I'm thinking it may have to do with that.

Thanks

[IMG][/IMG]

[timmy2]

Not used, Mine has a small rubber plug that fits in it to block it off.
Fill it with silicone and let it sit for 24 hours or find a cap that goes over it. A vacuum fitting cap will work.

[Guvnor]

Got it. Thanks for the info!

[kerthunk]

That is hooked up to the charcoal canister at the right side of the engine bay. Part of the fuel emissions system.

[Sunroof]

On my 1973.5T (first CIS) I have the identical fitting on my airbox. The fitting is for the hose that comes through to the rear from the charcoal cannister/vapor recovery jug in the front of the car (my model). I removed the hose from the box although its still near the firewall and plugged the fitting on the airbox. Many years since the 73.5T to your SC model. I would assume its for vapor emission return somewhere!

Bob
73.5T

[theiceman]

that is the vapour recovery port ... as mentioned .. but i am way more interested in WTF this is !!!!!! ??

[Sunroof]

undo the straps and remove the boot (slowly) and check it out. Looks like you might have a crack in the air boot and someone took the cheap way to a repair and sealed the crack. If thats the case....replace the boot!!!!!!!!!!!

[Guvnor]

[QUOTE=theiceman;7544604]that is the vapour recovery port ... as mentioned .. but i am way more interested in WTF this is !!!!!! ??

I was wondering if anyone was going to notice that. I think the PO used gasket maker to plug a crack in the boot. I already ordered the new boot from our host and was going to install this weekend. Do you think I can replace it without removing those fuel lines or lowering the motor?

[theiceman]

[QUOTE=Guvnor;7544653]

Originally Posted by theiceman

that is the vapour recovery port ... as mentioned .. but i am way more interested in WTF this is !!!!!! ??

I was wondering if anyone was going to notice that. I think the PO used gasket maker to plug a crack in the boot. I already ordered the new boot from our host and was going to install this weekend. Do you think I can replace it without removing those fuel lines or lowering the motor?

absolutely you can

its a bit tricky feeling around the back to unscrew a couple of hoses but i take mine off every couple of years to clean it up and make it look perdy

[Jdub]

Okay, when the car is running and you remove the oil cap, does the idle drop? If so, good; if not, an air leak.

That plenum (rubber boot) is toast - toss that in the trash where it should have ended up long ago. The PO probably wrestled the plenum off the throttle body and caused the split. Get a new item whose rubber is pliant.

EDIT: If there was no plug in that hose fitting, I just don't know how your car even ran? If you plug it, there will be a few adjustments you will have to make to adjust to the loss of straight-air input AFTER the air filter. Wow - that might explain the messy detris in the bottom of the airbox (clean all of that up BTW).

Also, interesting that you have solid fuel lines (metal) instead of the "plastic" types employed for our '78s. Is that the correct engine for your model year?

[Jerome74911S]

The worst part of this situation is getting unfiltered air, and the dirt that goes with it, into the engine. Since this dirty air is (was) getting introduced before the whole fuel injection system has its way with it, you need not worry about a 'vacuum leak' and there will not be any adjustments to do once you plug the unused port.

Correct, it is the port that once connected to the charcoal canister.

[Guvnor]

Thanks Jdub.

Yes I'm fairly sure that the boot is leaking gobs of air at the hose fittings in back. I can plug the air intake (in front of air filter) with my hand and the engine runs fine with no dip in RPM. Also no change in RPM with removal of oil cap.

I think the solid fuel lines are correct for 83. Was the last year of CIS so they really pulled out all the stops

[boyt911sc]

Originally Posted by Jdub

Okay, when the car is running and you remove the oil cap, does the idle drop? If so, good; if not, an air leak.

That plenum (rubber boot) is toast - toss that in the trash where it should have ended up long ago. The PO probably wrestled the plenum off the throttle body and caused the split. Get a new item whose rubber is pliant.

EDIT: If there was no plug in that hose fitting, I just don't know how your car even ran? If you plug it, there will be a few adjustments you will have to make to adjust to the loss of straight-air input AFTER the air filter. Wow - that might explain the messy detris in the bottom of the airbox (clean all of that up BTW).

Also, interesting that you have solid fuel lines (metal) instead of the "plastic" types employed for our '78s. Is that the correct engine for your model year?

Jdub,

You have the older '78 SC like mine and the OP has the '83 SC model with metal fuel lines. That hole from the side of the air box is allowing unfiltered and unmetered air but it is before the metering unit. So no adjustment NEEDED contrary to your suggestion.

Tony

Edit: Pete caught the blunder in my post. And made the necessary 'adjustment'.

[pete3799]

Originally Posted by boyt911sc

Jdub,

You have the older '78 SC like mine and the OP has the '83 SC model with metal fuel lines. That hole from the side of the air box is allowing unfiltered air but metered. So no adjustment NEEDED contrary to your suggestion.

Tony

I think Tony meant to say unfiltered and unmetered air.

[boyt911sc]

Originally Posted by pete3799

I think Tony meant to say unfiltered and unmetered air.

Thanks Peter for catching up the blunder!!!! I'll go correct it.

Tony