2004 Cooper S with plenty of miles (nearly 230k) Code P0456 just popped up. My gas cap is an OEM new cap from last July, so I doubted that was the issue. For kicks, I got a new purge valve solenoid because they are fairly inexpensive, but kind of doubted that was the issue. Sure enough, the code came back after clearing it earlier.

So I decided to look at the rubber elbow on the line that connects to the T just under the supercharger horn. Honestly it's a little crusty looking, but whole. For kicks I decided to pull the wheel liner and inspect the hoses at the canister. Suer enough, the purge line (running from the solenoid valve at the engine to the charcoal canister) has been rubbing on the dust cover at the lower part of the assembly. However, it doesn't look like it's worn clean through.

So now the question is: Is a line that is nearly worn through enough to case a small evap leak? I tried bending it to see if it would open up, but didn't seem to do so. If it's nearly worn through, is there any possibility of repair or do I need to just replace the whole line? It's a rigid plastic and I think if I were to try and section out the bad part and replace it with a rubber line, it might just be worse. Or maybe not? Perhaps epoxy over the divot and put a pice of rubber hose over that spot with a clamp to keep it tight?

Any input is appreciated.

 

It's probably worth trying the repair. I did something similar on my E46, the evap hose was a semi-rigid corrugated plastic. I cut the line and found a piece of rigid pipe that fit nearly perfectly inside. Applied liberal amounts of RTV and held everything together with a couple of hose clamps. Worked like a charm.

With the rigid plastic lines on the Mini I think your approach should work. But keep in mind the leak could be elsewhere and doing a smoke test is by far the easiest way to track down leaks.

 

Thanks very much for the feedback. It didn't seem like it had worn completely through, so I decided to wrap it with some flex tape and just clear the code because I needed the garage clear to work on the wife's car the next day. But yep, the light came back on so that wasn't it.

Two more inexpensive fixes to try. I've read where people disassemble the leak detection pump and grease the o-rings. It is likely an 18 year old part in a dry state, so that is likely. Also, I recently pulled the filter housing to fix a small crack near the fuel line, so it's also a potential that reusing the half year old tank seal (from when i did the fuel filter) might have produced a problem. I did that fix on new years eve, so it's possible it took some time to start leaking.

But yes, faiing that it's time to invest in a smoke machine. Luckily I had just had it inspected a couple of days before the light came on, so i've got a whole year to sort it out!

 

Hey there! I had this issue not too long ago before I had to smog.

The same T connection. underneath the supercharger was really worn out and the line just separated. It was throwing a check engine light and the evap monitor for emissions wouldn't complete. I peeled away the old rubber connector at the T joint and discovered that underneath it was a hose barb. If you connect the lines with a short rubber line and zip tie it to secure, it will connect and work just fine. Mine ran alot better!.

Funny how that little connection makes all the difference. All the other vacuum lines were fine, just the T connection that needed fixing. Cleared the check light with Torque and hasn't came on since. Smogged it the same day!

 

Just realized you were asking about the hose near the canister. I wouldn't rule out that T-Joint though. Mine looked crusty too and gave some gas smell in the cabin. When I touched the T connector, it disintegrated into many pieces. Maybe just change it to rule it out.

 

Thanks for the data point either way. I gave mine a good poke, and it didn't fall apart. It does look pretty dry though. What code was being thrown when your boot was leaking? Most of the videos I see about the P0456 code seem to insist the problem will lie somewhere between the leak detection pump and the purge valve at the engine. Then again, I saw another video where the evap leak ended up being the fuel pump gasket on top of the tank.

I did pull the leak detection pump yesterday and managed to disassemble, clean, and put some dielectric grease on the o-rings. I cleared the code again, so it will take a few drives to see if it pops back up. It was super dry and dusty in there, so it's a possibility.

I also mentioned that I had previously done some "surgery" to the fuel filter housing cap for a leak at the fuel line. Basically it was cracking at the top so I removed it and gave it a good cleaning to perform some light plastic welding. I pulled the cover under the seat to take a peak again and it looks like it is still leaking a very tiny bit. However, it's leaking gas rather than air. When it was really leaking (massive fuel smell after sitting parked in garage) it was never throwing any codes. So it's on the list of needs to be replaced soon, but I doubt it's the source of the evap code. I don't see any signs of leakage around the gasket area.

 

I just found out that is happening to me too. At the moment, I have it massively JB Welded with fibeglass string tape at the moment until I get a replacement. I'm glad though that I wasn't the only person seeing this, because I haven't seen this listed as a common issue and it just seems strange how it could have happened given it's the top just where the line connects. As if the stock filter housing is really weak and can't handle the pressure over time or something. Considering there isn't like an aftermarket "upgrade", I'm probably going to try and reinforce that area once I get the new unit to prevent this from happening again.

 

Right, I just think it's a thing when plastic is nearly 20 years old. I saw more than one thread about the fuel filter housing cap when I googled it a couple of months ago.

Well, the light came back on super quick, so the quick refresh of the leak detection pump did nothing. I might just be running into the point that I need to give in and get a smoke test machine. At this point I'm just guessing and would have to throw parts at it. Never a great strategy on BMW products.

 

Wanted to give an update because I hate when I find that thread that exactly describes my symptoms and there is never a resolution.

I gave up and bought a smoke machine. Ancel S3000 for around 200 bucks. A pretty nice unit for a home mechanic. I managed to crimp off the hose to the filter and plugged the line straight into the hose at the front of the engine where the purge canister connects. Pretty much immediately saw that the portion of the leak detection pump where the electrical pins are at was just letting out air big time. The o-rings I pulled and greased seemed to be holding just fine. I held my finger over it for a while and watched the gauge of the smoke machine to see if it was building pressure and it seemed to continue to climb with no smoke coming from anything else. I even popped the covers under the rear seat to make sure the gas tank seals weren't leaking at the pump or filter housing. Gas cap was holding just fine as well.

So I set the evap assembly on its side and dropped some super glue into the connector to hopefully let that sit and seal everything up. Left it overnight, hooked the smoke machine back up this morning and everything seems pretty good now. It let out a touch of smoke at first, but it stopped and pressure was building in the system. I couldn't hear the high-pitched squeal of air escaping as I did before so I think it's probably good for now. I will hook it all back up, clear the code, and see if anything comes back or not.

 

Hey good job. I had to replace that stupid pump a few years back. It will be interesting to hear if the glue holds up.

 

Thanks for the reminder. Yeah, the glue absolutely sucked. The connector needs FULL engagement on that thing and just a little bit of glue on the sides or corners just effed things up. I sent over an hour cleaning it out with acetone and pick tools before the damn thing would plug in again. I think I had read other folks using a bit of superglue, but I obviously did it wrong.

Once I realized how deep the connector went and saw that the connector itself had a strong rubber seal, I decided to blast the seal and connector with contact cleaner. I shoved some dielectric grease into the female part of the connector and also put some around the edge of the pump side where the rubber seal would sit. Did a smoke test with the connector all buttoned up and didn't get any smoke, so it should in theory be good.

So yeah, cleared the codes and got in a couple of drives. I will have a better idea in a week. I will probably check for pending codes as well if the light doesn't come back on. After realizing how snug that connector is, I'm curious to see if that wasn't the issue at all. I only got smoke with it unplugged. But even on the second smoke test, I just couldn't see it coming from anywhere else.

 

Well, no luck. Light eventually came back. I'm at a bit of a loss. Next plan is to remove the wheel liner under the filler neck to check for leaks there as well. I also looked at a parts diagram and there is a hose with three connection points towards the front of the fuel tank. Not really sure how to get a good look at those without dropping the tank, but I don't really have many places left to look for leaks.

I did notice a bit of a "popping" sound near/perhaps inside the fuel tank as it was pressurizing during the smoke test. I assumed I was activating some sort of check valve as the sound eventually went away as pressure increased. This is what prompted me to lift the covers for the pump and filter, but again I never saw any smoke there. I'll just have to give it another go.

 

Well, I pulled out both wheel liners and pump/filter covers for another smoke test tonight. This time smoke was absolutely blasting out of the leak detection pump where the flat face that the connector plugs into meets the body. I saw a couple of threads where someone would take that off and grease the o ring as well. Mine put up quite a fight to disassemble and it seems like it now doesn't want to seal. Funny enough, it wasn't smoking at all when I did the smoke test after getting the connector cleaned out.

Either way, I give up. I obviously have not improved the function of the seals and can't imagine making it any better. Ordered up a new LDP to install and we'll just have to see how that goes.

Oh and the "popping" sound seems to be related to the seal on the fuel pump. If I pressed down on the pump body, it seemed to stop. So perhaps that seal is going as well. Never saw any smoke from it, though. Perhaps the new LDP will be perfect and then I'll have smoke out of the fuel pump gasket.

 

I found it ironic that the LDP is itself the source of the leak. It made the $$$ for the new one even harder to swallow.

 

Well, one month later and quite a few trips on the car. No CEL and no stored codes for an evap leak. I guess the LDP was the issue after all. Perhaps if I hadn't attempted the glue and monkeyed with the connector end so much, the greasing of the o-rings would have sealed it up. Either way, glad to have it resolved.