BMW karma continues - incl. EVAP leak

[Craig in Canada]

So, I still get squeaking when cold since the t-stat replacement. I can't hear anything with a stethoscope from the wpump and I thoroughly cleaned the nearly new belts and pulleys when completing the job. The weather has been very cold so I haven't been inspired - so far. At least the new battery is working well.

Today I grabbed my Peake tool to reset a routine illumination of the "INSPECTION" indicator. I read the codes just to check that it was blank as usual and it wasn't. If I read the tool correctly it indicated an "11 FE --". If I have also read the manual correctly (from http://www.peakeresearch.com/manuals/fcx2.zip) that is an "EVAP large leak detected" code although the CEL isn't lit.

Now, you'll recall that I reported cricket squeaking from the LR (LINK) which is where some of the leak detection gear is, so I suppose it isn't shocking to one day get a code. Everything seemed intact when I removed the well liners before getting the Krown rust spray applied in the fall. I also went to inspect the gas cap and found a couple of things:

1/ the gasket seems intact
2/ the cap gasket area had liquid fuel on it, even though I think it's been weeks since I bought gas and I have just under a half tank
3/ I had just recently come home from the gym (a short trip, but a trip nonetheless) and there was no vacuum or pressure hissss when I released the cap like I believe there usually is.

Today is a "warm up" to around freezing after a good spell of 0-10F weather for the last couple of weeks. Again, I only found the code because I had the tool connected - no CEL (yet anyways).

Any tips on narrowing this down further other than disassembling the entire car and looking for a tear or clamp problem? There's been no fuel smell or sign of leaks. I would definitely notice that in the garage. I always fill the tank to full also so I'm hopeful that it isn't a hole in a tank or something.

I also have another question. I know there's a drain from inside the filler area into a tube that drains onto the ground. This is INSIDE the gasket for the cap. How is pressure/vacuum maintained when there's a drain tube back there? Or is it cleverly plugged by the cap?

Eurodavid should send me some Belgian chocolates to thank me for attracting this stuff over to this side of the pond... lol

[JimLev]

The flexible rubber boot around my filler pipe has a small hole in it that the drain tube connects to. My cap has no drain connection, it's a tight seal to the filler pipe.
I think for your Evap leak to set off the CEL you need 3 failures of that system.
If you do a reset then your back to square 1 again.

[Craig in Canada]

Jim I went out to take another look at it, I think you might be right and my drain comment should be disregarded.

The car has been out on two trips today - so four starts. I would be shocked if I randomly stumbled into a new problem that only takes three faults to trip a CEL. Although I guess it only "tests" during the set of conditions which makes my cricket go off and that was a long list - fuel level between certain values, car not running for many hours, this, that etc... I suppose it might take a while to build up multiple tests.

If my "cricket motor" itself failed, I'd expect that to throw a code of its own and not just detect as a leak - don't you think?

What about the gas cap seal? Does the system know a gas cap leak from any other? It looks like it's sealing properly all the way around (it disturbed some liquid I put on the rubber in a complete circle) but who knows.

I'm starting to wonder if this full car Krown application was a good idea. I've had a lot of my rubber trim go "sticky". My trunk seal wanted to stick to the lid until I cleaned it off with some pretty strong stuff. The hood seals around the cabin filters want to come off of the filter area and stick to the inside of the hood. Now I have an evap system leak - I bet there's a lot of rubber in that. Hmmm. I may be going back to always doing it myself in more targeted fashion.

Any tips on tracking down the origin of the problem? Other than the gas cap this doesn't seem like a frequent problem with the E39. I'm doing some googling at the moment. Since it may not test frequently, I have a reset tool and it doesn't smell or affect engine performance I hope I can limp along until better weather. I do have my emissions inspection this year, and I won't pass with an EVAP failure code in the system, that's for sure.

[JimLev]

You may have already found info from Googling.
IIRC it only can tell the difference between a small and large leak by the amount of current the leak detection pump draws.
The requirements for testing of this system are something like this:
The vehicle has to have been driven for 20+ minutes, the test will start after the vehicle have been shut off for 5+ hours.
The fuel tank needs to be between 1/2 to 3/4 full.
Ambient temp has to be between 20F to 95F.
Battery voltage between 11.5 to 14.5 volts.
When the above condition are met every second time the DME will start the test. Typically the test will be run once a day.

[Craig in Canada]

The current comment is interesting. What if the leak test pump is just knackered? You'd think they would have a special detection routine and diag code for that - maybe not. The problem is testing the stupid thing - it runs so infrequently it's really difficult to diagnose. Maybe on the bench it can be tested with straight 12V - hopefully it doesn't reside on one of the buses and need to receive an addressed command in order to run.

Do you know if the pressure/vacuum in the tank is natural (i.e. fuel warmed from being pumped through the engine bay expands and gives off vapour) or if it is created by the test pump? If the pump has a locked armature and the pressure is "natural" then I should still get fuel cap hiss. If the pressure is created by the pump or if there's a genuine leak then I won't get the hiss (like I've been seeing so far).

[JimLev]

The LDP is powered from F31 and controlled directly from the DME. You can connect it to 12 volts to see if it runs.
I'd pull the LR wheel and liner and start looking for cracks in all of the hoses that are up there. The charcoal canister, the pump, change over valve, etc are all connected with many hoses, some run back under the car to the fuel tank and one goes to the purge valve in the engine compartment.

[JimLev]

I think that there is a small vacuum in the tank, however I haven't driven my car in 2 months so I'm only guessing. The vacuum may only be there after testing, the 3-way valve may then switch over the tank to the charcoal canister which gets sucked into the intake manifold thru the purge valve.

[Craig in Canada]

It was chirping this morning, so I know it does something....sigh....

I think there are also components of this system in the RR wheel well too - an expansion tank or something. It's pretty complicated - I'm sure it'll be a breeze to find a crack. I should look into whether I can rent/borrow/buy some kind of smoke set up and just smoke test the system. That seems to be the 'official' troubleshooting method.

No CEL yet, at least. I should run back out and check the tank for vacuum.

[JimLev]

"Drive It Like You Stole It, A Sickness for Quickness"
The Bottle Rocket "King of Spray" 2 Stage Nitrous Oxide
Dare to be different and stand out among the crowd of me-to-cars!
No guts, no glory! Tire smoke, not traction control!
Zionsville all aluminum radiator to replace the 3 leak prone Nissens Radiators!

NOS Progressive 2 Stage Controller with port injection
Snow's Performance Methanol/Water Injection
Dinan downloads, VAC Under Drive Pulleys
Dinan Carbon Fiber CAI
Dinan Front Strut Bar
Electric Cooling Fan w/PWM controller
NGK Iridium Plugs
DDE Enhanced Angel Eyes, Smoked Lenses
Koni FSD's/H&R Springs, BAV Brass Caliper Bushings
Eisenmann Race Exhaust (from H8-Rain's car)
///M5 3.15 LSD
///M5 Sway Bars, Front & Rear
Energy Suspension Polyurethane Sway Bar Bushings
///M5 Gauge Cluster Rings ///M5 Lip Spoiler
///M5 Mirrors and Switches
Leather Z weighted shift knob (thanks H8-Rain)
Rogue “Octane” Short Shift kit w/WSR
Rogue Tranny Mounts
StopTech Brake Lines Front & Rear
Axxis Deluxe Plus pads Front & Rear
Staggered M Parallel 66, Xenons
Modified CDV, UGDO
Euro Storage Tray (thanks Zombywolf)
Redline in Diff and Tranny
Passport 8500 X50, Escort ZR3 Laser Jammer
G-Tech/Competition Pro Data Logger
Auto Enginuity OBD-II Scan Tool
25% Tint, X-Pel, LoJack
PIAA Driving Lights
BMW CCA Member Boston Chapter

[Ed CT]

from the top of the filler tube, over the top of the gas tank, and connects back into the tank next to the fuel pump under the rear seat port. There's also that drain tube for water that accululates inside the filler door well, it exits at the bottom of the wheel well.

[JimLev]

"Drive It Like You Stole It, A Sickness for Quickness"
The Bottle Rocket "King of Spray" 2 Stage Nitrous Oxide
Dare to be different and stand out among the crowd of me-to-cars!
No guts, no glory! Tire smoke, not traction control!
Zionsville all aluminum radiator to replace the 3 leak prone Nissens Radiators!

NOS Progressive 2 Stage Controller with port injection
Snow's Performance Methanol/Water Injection
Dinan downloads, VAC Under Drive Pulleys
Dinan Carbon Fiber CAI
Dinan Front Strut Bar
Electric Cooling Fan w/PWM controller
NGK Iridium Plugs
DDE Enhanced Angel Eyes, Smoked Lenses
Koni FSD's/H&R Springs, BAV Brass Caliper Bushings
Eisenmann Race Exhaust (from H8-Rain's car)
///M5 3.15 LSD
///M5 Sway Bars, Front & Rear
Energy Suspension Polyurethane Sway Bar Bushings
///M5 Gauge Cluster Rings ///M5 Lip Spoiler
///M5 Mirrors and Switches
Leather Z weighted shift knob (thanks H8-Rain)
Rogue “Octane” Short Shift kit w/WSR
Rogue Tranny Mounts
StopTech Brake Lines Front & Rear
Axxis Deluxe Plus pads Front & Rear
Staggered M Parallel 66, Xenons
Modified CDV, UGDO
Euro Storage Tray (thanks Zombywolf)
Redline in Diff and Tranny
Passport 8500 X50, Escort ZR3 Laser Jammer
G-Tech/Competition Pro Data Logger
Auto Enginuity OBD-II Scan Tool
25% Tint, X-Pel, LoJack
PIAA Driving Lights
BMW CCA Member Boston Chapter

[Ed CT]

[PimpSled]

CEL went on. Peake code reader 91 "Small EVAP Leak". Bought a new gas cap and error code and CEL gone for now.