Clean Fuel Tank Breather/Purge Valve???

[BHT2109]

Hey Everyone,

'91 318is. M42.

So, a while ago I got the 1263 code from the stomp test. This forum led me to think that something's amiss with the 'Fuel Tank Breather Valve' (p/n 13901711395):

https://www.bimmerforums.com/forum/s...tomp-code-1263

Seems to also be called a Purge Solenoid. Here is a RealOEM visual (#19):

https://www.realoem.com/bmw/enUS/sho...diagId=16_0107

Question: Assuming this valve is faulty, couldn't I simply hose it down with throttle body cleaner instead of shelling out $175 for a new one? For some reason, the internet is devoid of info on this. All mentions of it seem to reference its replacement, not its cleaning (which is probably a hint, but fingers crossed!).

Additionally, should I just replace the (more expensive) charcoal canister to help solve this problem?

Thanks for your help!!

B

[roguetoaster]

Certainly try cleaning it first, also make sure that neither of the hoses that you can acess are blocked. You shouldn't need to replace the canister, but you could check that air can pass through it.

[BHT2109]

Cool, thanks for the advice!

So to clarify: the hoses you're referring to are the two that are are connected to the valve itself, right? Or should I go ahead and check the hoses connected to the charcoal canister too? Couldn't hurt, I suppose.

Additionally, anyone think that a faulty/blocked purge valve is responsible for the gasoline odor that permeates the car after filling the tank? This really only happens when you 'top-it-off' (instead of simply letting the pump shut off automatically, man I hate NJ gas station laws!), so I figured it was maybe a cracked fill tube or something. Just wondering...

Thanks again!

[roguetoaster]

Yep, all of the rubber lines to/from the canister.

It might be the source, but it's more likely to be the rubber fill tube at the tank neck (rots, tank rusts), or the topside fuel pump gasket(s) as it's only once filled.

Finally, don't top off (or have to pump attendant do so), that fuel goes to the overflow tank and often evaporates instead of being used.

[TobyB]

Also, just 'cause,
pull the metal cover off of the vent
lines under your right rear wheelarch
and check that steel y.
They rust out, then the tank's at atmospheric pressure...

t

[BHT2109]

Sounds good

Thanks again for the advice, guys. I'll spew the throttle cleaner into the valve to see if the stomp code goes away, then I'll see if I can check the fill tube's condition.

I'll report back if there's anything noteworthy for the community at large...

B

[Boris3]

Resurrecting this thread for the same code on my 1991 318is. Shows up on my Bav Auto code reader Table 13, #24: Evaporative purge control valve. Real OEM part # 13901711395

BHT2109 did you have any luck with cleaning your old purge valve? Available new ones seem to be only genuine BMW at $425-475 a pop which is crazy.

Update: #13901726705 for a regular 1991 318i is only $110 and seems to fit per FCP Euro's site

[bmwman91]

The only way that the ECU will throw a fault is if there is an open-circuit or short in that circuit. It has no way of knowing whether the valve is stuck, a line is clogged, etc. It can only detect the current draw when it activates that output, and an error results if no current or way too much current flows. Check the wiring harness for damage, and measure the resistance across the 2 terminals of the valve to see what you get.

[Boris3]

Thanks that helps.

[Boris3]

Wiring harness looks fine, plug was a bit corroded so I cleaned that up and cleared the code. Valve measures 46 ohms.

CEL came back on the drive home this evening. Replaced the hoses, cleared the code, made it less than a mile and same result.

[bmwman91]

Strange. Per the factory repair manual, only an open circuit / broken connection will throw the error code. Your resistance is the proper value too. Does it only come up once the engine is warmed up? Maybe there is a small fault in the valve's solenoid coil and it opens when it expands from the heat? Make sure that both of the wires under the connector boot look clean and are not frayed where they are crimped into the terminals.

[Boris3]

Strange indeed. I was wondering about the ohm range since I thought I had read the number somewhere but couldn't find it. Your idea on a fault in the valve makes sense since the CEL/code had been coming up after driving for at least 15-20 minutes.. The valve may well be the original which is many years and miles ago, I know I never changed it since I picked up the car in 2012. I went ahead and ordered a new valve,so we'll see if that does it. Thanks again.

[bmwman91]

Cool, yeah let us know if the new one resolves the problem. Hopefully it does!

[Boris3]

Thought I'd update:

New part hasn't arrived yet.

Last week the CEL was intermittent: nothing the first day after clearing code and no CEL when turning the key, starting, or driving. Next few days It would only come on after driving for 20 minutes or so (mix of highway/street) but would be gone when restarting and driving the car until the next 20minutes in. This week Monday and Tuesday with gas gauge reading slightly more than 1/2 tank, no CEL when turning the key, starting, or driving. This morning into work with under 1/2 tank still fine. Same on the way home from work. Stopped and filled up at the station I normally use a mile from the house (didn't top off just used the auto shutoff) and immediately on turning the key the CEL was on and stayed on after starting and driving home. I did notice that the idle was rougher this morning and evening than the past few days and I half expected to throw a CEL but it didn't happen until stopping for gas. So could be that the fill up and CEL were unrelated? Anyway, we'll see what tomorrow looks like and if the new part makes a difference once it shows up.

Another thing, I can't remember but should the CEL light up along with the other cluster lights (brake pad lining, alternator, etc) when you turn the key but before starting? I seem to think yes and then it goes off after starting but mine has not been doing this since the CEL issue and code clearing. It has only been coming on when I first turn the key if I have the issues noted above: then it's on at the start and and stays on.

Might be unrelated but my cluster may be acting up as well. I had faint/ghost alternator-parking brake-oil lights that were fixed by replacing the alternator. The CEL issue started a few weeks later after replacement (Bosch 80amp). Granted too many wild cards since the weather also got much colder for the first time. My brake pad sensor light also continues to have a mind of its own even with the alternator swap. Sensors are removed and wired together and has not been a problem for years. Rechecked the connections and all good. Sometimes it comes on and stays on, sometimes it doesn't. Could be fried resister in the cluster No chewed wires or rodent carcasses to be seen.

Anyway, joys of old cars!!

[Boris3]

Hopefully last update:

New purge valve arrived: as an FYI out of the box it measured 43 ohms. I remeasured the old one again cold once removed from the car at 42. Installed the new one and went for a drive...and after about 30 minutes had a CEL again. This left wiring.

Turns out rodents strike again. Found a very small nick in the plastic covering over the wires about 3" away from the plug, peeled the covering back and found the ground wire with the same nick in the insulation, and the wire itself partially broken. Explains why the issue was intermittent. Fixed the wiring and so far so good.