Three evaporative canisters?

[BrandonMc]

Do I have a rigged up bypass evaporative canister?  You see, there's a main evaporative canister, and an aux canister per my diagram. But apparently another canister is tee'd into the main canister lines where I circled the diagram. This secondary canister has a strap and is welded to the frame. No other diagram for this situation exists.


I'm wondering if this smaller canister, if I need to eliminate it because it was rigged up to bypass the main non-working canister, or some other such reason. That extra canister is exactly like the main canister, but smaller. Does a two canister type system mean the main and aux only? Or is there in fact two vapor canisters? My sticker on the air cleaner body also says it's a two canister system, and I'm scratching my head trying to figure this out.


Thank you

[BrandonMc]

Everything I've looked into suggests that this is indeed a smaller vapor canister added to bypass the original vapor canister. A truly weird rigging where someone likely bought a smaller vapor canister and tee'd this into the original system while leaving the original system in-tact. (Meaning nothing suggests, no one mentions, or no diagrams exist) I will remove this smaller can and install a brand new primary vapor canister.

[Rickf1985]

Mine has dual canisters and both were hooked into the system. Both bracketed to the passenger side of the radiator support. they are actually still there and hooked up, I did not remove that part of the system since there are too many modifications that need to be made to the gas tank and related parts if you remove that and it causes no issues with the running of the engine or mileage so best to leave it alone.

[BrandonMc]

Rick, I was hoping you would be able to give me some insight on this.

While reading the p30 motorhome chassis manual, it appears that a dual canister system is used in the two fuel tank designs. I have a single gas tank, 60gal. I suppose there's still a lot of vapors coming from tank that large. I wonder why this isn't mentioned much of anywhere else.

[BrandonMc]

Hello,


I just want to report I finally found the solution to this. There is supposed to be one large main canister, and an auxiliary canister - the two canisters. The weird thing was an evaporative canister for an old corvette that is no longer manufacturerd was tee'd into the older main canister and welded to the frame of the Winnebago with a strap. It seemed intentional on the part of winnebago perhaps. I called Chevy and Winnebago, and neither could answer my question.

I've since replaced the main canister, and eliminated the tee'd portion entirely, and it did seem to make a difference in the fuel system vacuum.


Refer to page 7-96 on the p-30 chassis manual

[andrei23]

I, too, am stumped by this "mystery 3rd canister" issue.  After a recent trip, my engine overheated, and while I've found and replaced the ruptured hose, I also found some other hoses (from this 3rd canister) just hanging there.  Wondering if anyone knows the correct way to either connect it, or bypass it?

There's a line coming down from right under my air filter, currently not connected to anything, which I'm assuming goes either through this mystery 3rd canister (labeled #1 in the photo above) via either port 2 or port 3 (see image below of the top of canister), and then (I assume?) connects to the T which comes from my primary primary canister (#2 in top photo) and goes to the PCV valve.  Port 1 on this mystery canister T's off from the line labeled to "to fuel tank" in most service manual diagrams.  Any thoughts?

The primary cannier (#2) has 6 ports.  The outer single port goes to the auxiliary canister (which isn't either of these two, it's up front by the radiator).  The inner single port hits a T and goes into port 1 on the mystery canister #1, and after the T continues to a metal tube (I assume heading to the fuel tank).  The remaining ports are duel-ports, thinner cable on top, thicker on the bottom.  The outer dual thick hose merges with the inner thin hose, the outer thin hose is accounted for.  That leaves the inner bottom thick hose from the inner dual port.. and I'm trying to figure out where that's supposed to go as it was also just hanging there.

A = port 3 on mystery canister, but goes to?
B = comes down from under air filer
C = T's off from fuel tank and primary canister
D = port 2 on mystery canister, goes to?
E = I assume connects to B?  Or perhaps A or D?
F = where PCV valve attaches

Would love some help in reconnecting these and cannot find a diagram which includes this 3rd canister anywhere!  It's somewhere on the way way "to fuel tank" is all I know.  The only clues are the label "Introl" on top and the number "0717" stamped on the bottom.

Any ideas?  Many thanks in advance!

[andrei23]

Now for the primary canister:

G is what I need to figure out.. connects to B?  Or perhaps to A or D on the mystery canister?

H and J merge together (this is on the diagram), and come to the T which labelled E and F above (F being where the PCV valve goes, per the above diagram).

I is the other lead (along with B, above) which goes up under the air filter.

K goes to another T where one lead connects to C on the mystery canister, and the other to a metal tube ("to fuel tank" I'm assuming).

And L is our line to the auxiliary canister up front by the radiator.