other Charcoal Canister Project

[John Southerland]

Hello all, I've been keeping busy with my projects and recently had a wild idea to install an E36 (97 328i) Charcoal Canister into my E10 2002. I just finished a project on my E36 and fell in love with the location and engineering of the charcoal canister, so I picked one up on eBay for <$50 and decided to try it out. I didn't have anything on my gas tank vent so I had it capped while sitting and wanted to do something different than the prescribed vent canister hanging from the support in the trunk. So here are the pictures, just ran a 3/8" hose from the vent to the tank input on the canister, capped the return to the E36 intake (for recycling), and left the solenoid disconnected (open) to the 3/4" exit port, just sitting open for now (I may route this outside later, but it is post charcoal, so I'm not too worried).

 

The biggest problem I can foresee is if I fill the tank and expansion causes gas to pour directly into the canister, am I missing anything else? Is this stupid? I'm hoping an engineer will tell me if I've accidentally created a bomb of some sort, though I'm not terribly worried of that with this simple system. I'm awaiting a plastic cover from the same E36 location, to go over the canister and allow the spare tire to sit in the same place. It is a very good design, and one I am happy to borrow for the classic.

Thanks, John

[John_in_VA]

16 minutes ago, John Southerland said:

The biggest problem I can foresee is if I fill the tank and expansion causes gas to pour directly into the canister, am I missing anything else? Is this stupid? I'm hoping an engineer will tell me if I've accidentally created a bomb of some sort, though I'm not terribly worried of that with this simple system. 

 

That would be my concern (siphoning), and may be why the original vapor canister was fitted high in the trunk.  There was also a charcoal filter fitted in the engine compartment.

[John Southerland]

I ran a cheap clear hose so I could inspect it the first few weeks and see how much it is getting fouled. I may try running the hose up to a high spot in the trunk and then back down if that is the case. At least then the pressure would have to be so great as to fight gravity a little more in order to flow, and given that the vent tube of the tank isn't deep, I don't expect a siphon effect to be able to start. I can't be sure without some experimentation. The thing about going off the reservation, like this, is that you can't always anticipate how it will fail, so I may have to revisit this a couple of times. My ultimate goal is to reduce the fuel smell in the trunk, and have fun with this, so far both seem to be a success.

[jimk]

You need to understand how the system works on the E36 before setting up something here.

Std operation of a canister capture system is to adsorb hydrocarbon vapors in the activated carbon and later recharge by purging (suck out the hydrocarbons) when the car is running to the engine intake.  That is what the solenoid valve is for to shut off purge/vent when the engine is not running.  The ECU performs this control.

If the canister is not purged, sooner or later it will be fully loaded and the smell comes back.

I don't believe there is any dip tube on the tank return nipple, so it shouldn't siphon, just overflow in your case.

The original early system only acted as a vent to the carb and as a reservoir in the event of a full tank and fuel expansion occurs.

[John Southerland]

Jim,

This is great information, I tried to find some specs on the canister from the E36, and it was sparse, but I read elsewhere that the solenoid was open until closed by voltage that allowed the vapor to instead exit the second smaller connector to recycle vapor into the intake (when the solenoid was given current). Correct me if we are not saying the same thing here. So if I just leave the solenoid disconnected would that not allow a constant purge?

 

Thank you for the explanation. I'm not yet comfortable with what I have done here.

[jimk]

Your thinking is correct.  But what I meant by purge, is that it is a forced purge by the intake sucking air thru the canister to pull the vapors out.  Just an open vent won't do much for drying it out.  But is shouldn't be a hazard if the solenoid is not open if it is vented to the outside. 

If you search around for online electrical diagrams for the E36, that may help understanding what goes on.  They will show the solenoid being fed from the ECU and there may be notes telling when the electrical power is applied.  I have seen them in my travels but don't have a link.

[John Southerland]

I didn't think about the forced purge by draw of air. I may need to look into how best to emulate that, or just let the canister dry out by nature itself. I've got some manuals here on the E36, I'll dig a little deeper and see if anything is noted about the canister. Most everything I'm able to find online is just written by kids that think the extra weight of the canister is slowing down their ride. That is most likely the reason I was able to get a $440 canister for $44 on eBay. Crazy kids

[John Southerland]

Wow, I finally opened up my Bentley manual on the E36, and for once the wealth of information is needed here. It turns out the valve is closed while the car is running and the system is sealed during operation. I'm not going to need all that so I should be good, but in the E36 a container is between the canister and the tank to provide a fuel overflow and pressure regulation. I'll look into putting a tank in hanging in the top corner of the trunk to make sure this canister doesn't get drenched in gas.

 

It would be an interesting exercise to put an E36 engine into a 2002, complete with OBD2. With all this metal, there may actually be enough space. It would be a monster with terrible stopping power. 

 

[carpainter]

Will a  member explain where the vapor canister hoses go? one from the gastank and the other to the intake manifold?

 

Is the can supposed to have contents ? draw? because mine seems empty and the air just flows thru?

Is it supposed to have a vacume hose from the manifold ?

guess I need a new one.

Thanks 

Edited August 21, 2016 by carpainter

[John Southerland]

Looking at the canister from the top, the outer most blue line is the inlet from the gas tank vent, and the inner most line is supposed to run to the intake (but you can ignore that for the 2002, because emissions and we don't really worry about that on these). The can should contain charcoal. This is my extravagant technique to eliminate fuel smell and fit under a spare tire. Any charcoal canister will work. This one just happens to be a design I enjoy. The large output line is to vent out of the car, and should always be open, because we don't need to wire the shutoff valve. (it is open when no current exists, allowing air to flow through the charcoal) If you don't have an E36 charcoal canister handy, you could use a coffee can and a bag of filter charcoal, but this is just more artistic.