Vacuum Question

[timsweet]

I just installed the canister that traps the vapors from the gas tank.

Of course the vapor then moved in to the ERG, but I no longer have the ERG, where should it go?

 

[Jeff73Mach1]

run it to the underside of the Air cleaner housing so that when you start the car any fumes are pulled into the carb

 

[Don C]

That looks like a regular vacuum reservoir. The fuel vapor canister has a small hose that connects to the vent line from the tank and a large hose that connects to the air cleaner base. The fuel vapor canister is also filled with charcoal granules and is typically blue.

You can see a picture in this thread:

https://www.7173mustangs.com/thread-vac-can-mystery

 

[timsweet]

That looks like a regular vacuum reservoir. The fuel vapor canister has a small hose that connects to the vent line from the tank and a large hose that connects to the air cleaner base. The fuel vapor canister is also filled with charcoal granules and is typically blue.

You can see a picture in this thread:

https://www.7173mustangs.com/thread-vac-can-mystery

That is what was connected to the vapor line from the gas tank - when I removed it.  The large line came to can from the gas tank and the the small line when to the egr valve.   Doesn't mean it was correct but that's how the was driven.   There is no other canister.

It was black when I removed it and I repainted black.

What am I missing?

BTW the link doesn't work  https://www.7173mustangs.com/thread-vac-can-mystery

Thanks

 

[Don C]

The hose that runs from the vapor canister to the air cleaner is 3/4" diameter.

Try this one:

https://www.7173mustangs.com/thread-vac-can-mystery-help?highlight=Vapor+canister

 

[timsweet]

The hose that runs from the vapor canister to the air cleaner is 3/4" diameter.

Try this one:

https://www.7173mustangs.com/thread-vac-can-mystery-help?highlight=Vapor+canister

That was perfect.    So clearly mine was not connect properly and the Vapor canister is missing.

 

[timsweet]

Going back and looking at the videos I took while take everything out of the engine bay, show that the previous owner used the vacuum can as a replacement for the charcoal canister. There was no heater core and the A/C was removed so there wasn't any need for the cooling/heating system to be functioning.

I just need to pick up a charcoal canister now.

Oh...Yikes....$150?

 

[73pony]

I might have one. I can do some digging this weekend. It will need some new paint I'm sure if I have one. I will PM you if I find one. Yours for shipping only if I have it and you want it.

 

[timsweet]

I might have one. I can do some digging this weekend. It will need some new paint I'm sure if I have one. I will PM you if I find one. Yours for shipping only if I have it and you want it.

Jason,

Thanks.  I dropped you a PM.

Tim

 

[72HCODE]

the black canister is the A/C vacuum reserve canister

the Blue canister is the Fuel Vapor Return Charcoal canister.

the blue canister is used to vent the main fuel tank and prevent implosion from occurring due to negative atmospheric pressure in the main fuel tank caused by the fuel pump sucking out the fuel going to the engine. the Venting is then captured by the fuel vapor return canister and sucked out when the engine is started up through the air cleaner base. when vacuum is high the fuel vapor canister is sucked out, when vac drops like accelerating then it dumps air back into the fuel tank it all equalizes

since it is venting and exchanging air. the vapor return canister also helps keep the fuel from going bad, stops rust from forming as it also sucks moisture out of the tank.

This was changed due to emissions laws originally mustangs used a vented gas cap in 71 the law required the fuel vapor to be captured and then it made sense to make the engine reuse the vapor through the intake. so previous mustangs did not have this canister. for 71-73 this fuel venting also captured venting from the original carb fuel bowls. hence a larger hose from the fuel tank goes to the can and a smaller from the carb goes to the can then a larger paper/foil hose connected to the air cleaner base that sucked the vapor through a filter into the intake and down into the engine to burn. as a side effect this also gets rid of that fuel smell old cars have when sitting around and the fuel vents into the garage and car interior.

Also in case of roll over and the car ends up upside down the canister holds fuel from draining from the tank to the engine bay where a fire can start.

honestly all around it is a good thing.

The black A/C vacuum reserve canister job is to keep a reserve of Vacuum (similar to the brake vacuum booster) for running the A/C system and helping to compensate for the slight vacuum leak the A/C system causes. it drives the Vacuum motors for the A/C system and acts as a buffer for vacuum loss and engine backfire protection.

When you accelerate and vaccum drops a properly working A/C vacuum reserve canister will stop the A/C system from shutting off and turning back on as vaccum builds at idle. it takes vacuum load off the engine as well when accelerating.

there is a reed valve inside the can that goes bad over time. so if you accelerate and you feel the A/C system stop blowing air then it comes back replace the A/C vacuum reserve canister the reed valve is blown, you can also test it manually blow air into the can and then try and suck it out, the reed valve will only allow air to flow one way, if you can blow and suck air out the reed valve is blown. the blown reed can also act like a slight engine stumble when heavy accelerating, because suddenly the vacuum drops more then it should and acts like a vaccum leak.

 

[timsweet]

A couple other notes.

With the addition of the 4bbl carb the old air cleaner assembly will not fit, which brings me back to what to do with the at the least the fuel vapor.

I haven't see any air cleaner units that would if and have the same vent/vacuum connections.

Tim

 

[Don C]

Most aftermarket air cleaners come with an opening in the base for an emission hose. If it doesn't you can get a connector like this one:

https://www.summitracing.com/parts/edl-1205/overview/

 

[72HCODE]

you can drill a hole in the new air cleaner base and install a barb then hook up the vapor line to that.

most aftermarket cleaners have a PCV barb, you can install another one a bit away from the pcv barb.

after market carbs have the fuel bowl vents fitted above the carb ventries so they vent into the intake with the engine running and are contained by the air cleaner element and the top cover when the engine is off, so you don't have to worry about the fuel bowls,, the original carb had the vent outside the aircleaner base area on the side of the carb base body so in that case you needed to run a hose back to the vapor can.

I'm running a stock V4 air cleaner base on a Holly 750DP 4 barrel. its from a Q code with AUX intake port vacuum activated.

 

[timsweet]

you can drill a hole in the new air cleaner base and install a barb then hook up the vapor line to that.

most aftermarket cleaners have a PCV barb, you can install another one a bit away from the pcv barb.

after market carbs have the fuel bowl vents fitted above the carb ventries so they vent into the intake with the engine running and are contained by the air cleaner element and the top cover when the engine is off, so you don't have to worry about the fuel bowls,, the original carb had the vent outside the aircleaner base area on the side of the carb base body so in that case you needed to run a hose back to the vapor can.

I'm running a stock V4 air cleaner base on a Holly 750DP 4 barrel. its from a Q code with AUX intake port vacuum activated.

I'll re-watch the install video for he my carb, I didn't see it mentioned.

I wondering if the V4 Air cleaner will fit my Edelbrock 1413 4bbl carb?  

BTW  if you have used Edelbrock tech line that are great!!!  Can't say I as thrilled that the guy said my 800CF was too big for the engine...but...

thanks

 

[72HCODE]

i have used an Edelbrock 600CFM 4 barrel carb (do not remember the exact model) and used the stock ram air intake with it. this was maybe 10 years ago.

I got rid of the Edelbrock for a bunch of reasons and went to holley. Holley and holley style carbs work better on 71-73 mustangs this is due to the throttle cable setup and transmission kickdown geometry for an automatic.

everyone likes one or the other for the carb setup. earlier mustangs i prefer a Edelbrock on.

the big deal is swapping the intake manifold out from a Spread bore to a square bore so you can fit 99% of the carburators on the market today. usually you need to add a Carb spacer as well to raise the carb on the square bore intake so the linkages clear everything.