2.9 coal canister removal?

[sebackman]

Hi all,

Is there any value to remove the coal canisters back in the the trunk of an old S3 (2,9). I don't think anything has been done to them since they left factory. There is no problem and they are not leaking just though it might be "time"? Or is there some kind of service to them recommended?

The search engine of PH it not very good since the swap to Google. Does anyone know how to get the old one where you can limit search to the forums you want?

Thanks

//Rob

[GreenV8S]

It is maintenance free and designed to last the life of the car - I don't see any reason to remove it unless it became blocked for some reason.

[sebackman]

I'm switching to an Emerald system soon and then the control for the purge valve will not work, as far as I understand.

My thought was to remove all the hoses and just have a breather hose from the tank and leave it open under car in the rear with some kind of filter on top.

That would take out a number of hoses including the long hose to the plenum to the purge valve.

Would that work?

[magpies]

Don't just hang the breather hoses down, run them to a catch tank with a breather filter. Cheap enough on ebay. I do not like the idea of recirculating oily fumes through the throttle body. I also run an Emerald ecu on my Jag engined S1

[sebackman]

Hi magpies,

Thank you for info and picture.

Did you connect the tank breather hose that normally goes into the coal canisters to the long hose into the catch tank?

If so, that means that you still have a long breather hose from the tank to the front of the car.

Why not place the catch tank in the rear? No natural space to vent into open air?

Have you emptied the catch tank to see if anything actually ends up in there? Its a long hose to get there from the tank.

Thank you
//Rob

[GreenV8S]

magpies said:

Don't just hang the breather hoses down, run them to a catch tank with a breather filter. Cheap enough on ebay. I do not like the idea of recirculating oily fumes through the throttle body.

I think you may be confusing the fuel tank vent with the crank case breather. The only thing that should come out of the tank vent is petrol vapour. In the pre-cat days this would have been vented to atmosphere via the filler cap and it's perfectly reasonable to do that if you want to remove the vapour recovery system..

[sebackman]

Hi GreenV8S & magpies,

Sound logical.

I often have a problem filling up the tank , the pump shuts off and I guess that the tank ventilation is not good enough so there builds pressure in the tank when filling. Or the canisters are clogged.

Back at the canisters there are 3 hoses connected. One comes from the tank I guess, one goes to the plenum and one is connected to the tank filler hose just under the tank lid.

How do you propose to connect the two remaining hoses (ie tank vent + tank neck hose)? The long one to the plenum can just be discarded I guess?

I think what Magpies meant was that the coal canister drainage is connected to a electronic purge valve in the engine bay and then merged with the right side valve cover before connected to the plenum. So by removing the plenum connection from the coal canisters the right valve cover would be connected direct to the plenum as it is now. I guess he took the valve cover ventilation from both sides and run it to the "catch tank".

On my car the left valve cover ventilation is really the oil filler cap and the hose from there goes into the air filter and winds up in the plenum that also.

Thank you
//Rob

[GreenV8S]

sebackman said:

I often have a problem filling up the tank , the pump shuts off and I guess that the tank ventilation is not good enough so there builds pressure in the tank when filling.

This is common in my experience and I believe it's to do with poor flow within the filler neck rather than any backpressure in the tank. Fuel pumps are sensitive to even the tiniest amounts of liquid splashing into the venturi section. I find it helps a lot to turn the nozzle through 180 degrees (so the hose points straight up, iyswim). I think this puts the venturi input against the top of the filler neck where it is less likely to get splashed - it seems quite effective, anyway.

[magpies]

GreenV8S said:

magpies said:

Don't just hang the breather hoses down, run them to a catch tank with a breather filter. Cheap enough on ebay. I do not like the idea of recirculating oily fumes through the throttle body.

I think you may be confusing the fuel tank vent with the crank case breather. The only thing that should come out of the tank vent is petrol vapour. In the pre-cat days this would have been vented to atmosphere via the filler cap and it's perfectly reasonable to do that if you want to remove the vapour recovery system..

Yes I did confuse the engine oil breathers and the fuel.

[sebackman]

Hi GreenV8S

I do the same, ie turning the handle, when filling up, with mixed success.

Did you ever find a cure for the bad tank ventilation?

Do you still have the canisters (were they ever present on the V8's?) or have you deleted them? If so do you have two breather hoses, one for the tank and one for the neck?

Thank you
//Rob

[GreenV8S]

Mine is catted and has carbon canisters etc that come with that. among other things, the vent in the filler cap is sealed off with what looks like epoxy so that it only vented via the canister.

The vapour recovery system is blocked off on mine since I cba to get it working with Megasquirt. I assume it works by virtue of the fuel filler cap seal being thirty years old and not sealing particularly well. If it was a problem, I'd reinstate the vent on the filler cap.

[sebackman]

I will take it apart during winter and ditch the canisters and see how I can went the tank under the car with a filter. This also means removing canister purge hoses giving less stuff under the hood.