Carbon canister vacuum hose

[gotham22]

Can someone tell me what connects to this t fitting from the carbon canister? I cant figure out where this hose goes.

 

 

[Captain Obvious]

I think that "T" is supposed to go to the same place your distributor vacuum connects to.

It's a ported source on either the front carb, or the EFI throttle body (depending the year) and "T" to the distributor advance and the carbon can.

[Yarb]

@Captain Obvious Correct on my 78

[gotham22]

So these should not connect to each other?  The "t" should feed them both

 

[kickstand80]

The legend is on the carbon canister. The way it is supposed to work is ported vacuum is routed from the bottom of the throttle body to the thermo-vac switch mounted in the thermostat housing. When the engine is hot the thermo-vac switch changes and routes ported vac to the distributor and the carbon canister. The vac at the canister opens the purge valve so that fuel tank gasses that are absorbed by the carbon in the canister are sucked into the intake, this was an emissions thing, sealed tanks so that gasoline fumes are not vented to atmosphere. You can bypass the thermo-vac switch, and route ported vac straight to the distributor so you have vac advance at the distributor all the time, not just when the engine is hot. Limiting the vacuum to the vacuum advance when the engine was cold was an emission thing. You may also find a "T" at the distributor that sends vac to the EGR valve at the same time as the vacuum was sent to the carbon canister. You can delete the T so that the EGR valve never opens again(also an emissions thing)

[Captain Obvious]

On 7/22/2022 at 5:54 PM, gotham22 said:

So these should not connect to each other?  The "t" should feed them both

Correct, those two things you have circled should "T" together along with the carbon can.

[Captain Obvious]

On 7/22/2022 at 9:38 PM, kickstand80 said:

The legend is on the carbon canister. The way it is supposed to work is ported vacuum is routed from the bottom of the throttle body to the thermo-vac switch mounted in the thermostat housing. When the engine is hot the thermo-vac switch changes and routes ported vac to the distributor and the carbon canister. The vac at the canister opens the purge valve so that fuel tank gasses that are absorbed by the carbon in the canister are sucked into the intake, this was an emissions thing, sealed tanks so that gasoline fumes are not vented to atmosphere. You can bypass the thermo-vac switch, and route ported vac straight to the distributor so you have vac advance at the distributor all the time, not just when the engine is hot. Limiting the vacuum to the vacuum advance when the engine was cold was an emission thing. You may also find a "T" at the distributor that sends vac to the EGR valve at the same time as the vacuum was sent to the carbon canister. You can delete the T so that the EGR valve never opens again(also an emissions thing)

I'm not sure the Z had a temp controlled vacuum switch. I think the ZX did, but based on the pic above, this is not a ZX.

And also on the Z, the ported vacuum signals for the distributor/carb can are a completely different source than the one that is used for the EGR system. Similar in concept, but completely different ports and actuation loads, etc. The "T" pictured above has nothing to do with the EGR system.

[kickstand80]

My bad, I just assumed it was a ZX. The post does not say what year.

 

[gotham22]

Thanks captain obvious.  Kickstand, my bad for not saying it is a 78 280z

 

[Captain Obvious]

10 hours ago, kickstand80 said:

My bad, I just assumed it was a ZX. The post does not say what year.

No biggie. The only reason I could tell it wasn't a ZX was because of the location of the BCDD.