Replaced fuel vent valve - now unable to fill gas tank

Have had a couple of instances of P0422 (minor vapor leak) recently and an occasional fuel smell in the cabin. Replaced the gas cap, however that did not solve the problem. Replaced the fuel vent valve yesterday. Replacement went smoothly mechanically. However, when I went to fill the tank with gas, it would not fill at all. I am wondering if this has happened to anyone else before. Thoughts would be greatly appreciated.

Fuse E6 ? http://www.renntech.org/forums/topic.../?_fromLogin=1

Removed...duplicates Schnell Gelb's post.

Thanks will check that..

There is a magnetic switch that goes into the housing of that valve, not mentioned in the pelican parts how to article...Looks like If you didn't know to put it back into the housing it will not function, and you won't be able to fill the tank. Magnetic switch

yep, that is the issue. I remember seeing it and wondering what it connected to.. Back into the fender we go.

I was having an issue filling the tank so I just did this same repair on Friday. Though I haven't tried filling my tank yet to see if the valve replacement fixed my issue. However, during my installation, I didn't see this magnetic switch. Do all 996's have the magnetic switch? I may have to dig into the fender too. Mike

This part is more commonly refered to as a "Reed Switch" or valve? http://forums.pelicanparts.com/boxst...ic-switch.html

^^^^ I swear I didn't see this switch while swapping the valve... it wasn't attached to the valve, or dangling anywhere...interesting... I guess I'll find out when I go to the gas station shortly and, mentally prepare to do the job again. Mike

You will note that when I put in a new fuel line vent valve, I didn't notice it either. I even took a picture of the original valve to make sure I put everything back the way it was supposed to be. But when I went to button everything up, that sensor was hanging. I frantically googled to find out what it was and even posted here: https://rennlist.com/forums/996-foru...is-sensor.html Funny story about how I knew I needed a new one: I was driving back from where I bought my 911 and stopped to fill up (it was a 250 mile trip). I was having a ball driving my new(to-me) sports car down the highway. I got back into the car, and it wouldn't start. It would crank, but not ignite. Several tries produced the same results. So there I am, having just dropped $$$ on a car that would not start. I had visions of the cost of flat bedding it back home, having a mechanic sort out the problem and sat in the car for a few minutes, cursing my very existence. Before I gave up and called a tow, I gave it one last shot and it fired up first try. Some quick googling on "966 won't start after fuelling up" lead me to the fuel vent valve. $70 later and it was fixed...well, $70 and several hours cursing my existence trying to find out what that sensor was. BTW. If you look about 1/2 the way down the page on the Pelican Parts How to you will see this exchange: Comments: I have the same problem as Allen from Dec 1 2013 above I installed a new vent valve to solve hard starting. I have the same sensor hanging by 2 wires and now can not fill with fuel. Where does the sensor go, will that solve the problem? Followup from the Pelican Staff: Can you share a photo of the sensor or can you identify it from our tech article and point it out to me? - Nick at Pelican Parts Comment : See the attached photo. Followup from the Pelican Staff: GREAT! Thanks for sharing the photo. There is a small black plastic molded piece that is fitted to the filler neck. That magnetic switch pops into that black piece. It should be obvious that it fits inside of it. WITHOUT it installed, you will have the issue you are experiencing. - Nick at Pelican Parts There are several other people with the same comment. Why they haven't updated the how-to with this knowledge is unknown. Their failure to do so is no less than criminal.

^^^^ Oddly enough, I was able to fill my tank without the pump stopping??? Everything seems to be functioning properly (though I developed a new issue while driving to the station...but, that will be posted in another thread). Does the '99 have the reed switch? Mike

Here is a link to the Pelican How to referred to above: http://www.pelicanparts.com/techarti...Vent_Valve.htm scroll down to : November 21, 2013 October 5, 2014 Obviously a very confused subject that needs a comprehensive,updated DIY guide

^^^^ Indeed. Especially for a Noob like me! Mike

Hopefully the next time we have this question(& it is frequent) somebody remembers Mike's helpful comments.

I actually did this repair recently AND ensured the reed switch went back into place. I also took the time to put a screenshot in the Pelican Parts article. Problem is I still have the fuel filling issue. The replacement part I used was new from Porsche dealership. Is there another way for me to diagnose what is going on besides re-installing the same part again? It took me 15 minutes today to add 5 gallons of gas to the car. ETA: Fuse E6 was blown (thought I checked it before) -- I replaced it and it blew again. Where should I be looking for this short occurring? Is it back under the fender?

Quotes source post: 14097149

Try this link - you are not alone !But PLEase tell us what works for your case to improve the knowledge base. https://rennlist.com/forums/996-foru...revisited.html

Quotes source post: 14098036

I don't see any of the TSBs. For example here: https://www.renntech.org/forums/part...g-out-of-fuel/ or https://www.renntech.org/forums/part...-modification/ I'm a paying member on renntech as well (as of 10/2016). Not sure if I am just blind and don't know where to click to download the TSB.

More Troubleshooting Info: In looking for the "short" on E6 I did some testing on the wire harness frequently referred to as the Telephone harness behind the driver side footwell: I4PuqJ0.jpg According to Loren's post here: https://www.renntech.org/forums/topi...#comment-23826 The pinouts should be: My volt meter is set to this: LFXW0HR.jpg Here's my reference of the E6 Fuse location: I get a tone on the following (no key in ignition): Red from multi meter to Brown on harness Red from multi meter to Green/Black on harness Red from multi meter to Red/Green on harness Red from multi meter to Red on E6 fuse connection I don't get any tone: Red from multi meter to Green on E6 fuse connection When testing for voltage (and turning DMM **** to far left) I get: Red on E6 fuse connection = 0 Green on E6 fuse connection = +12V I'm guessing this means that somewhere between the Red on E6 Fuse connection and Red/Green on harness I have a short. I'm a little confused now and am not bright enough to follow the detailed wiring diagrams. Armed with this information, can anyone help guide me on how I can find the short without having to unravel the whole dash and harness? I don't see anything obvious on the end of the harness (nothing looks chafed against the airbag controller) and I don't see any exposed wire.

If you are connecting the black cable from the DMM to ground, that would explain some of this. How many Amps was your old, blown E6 fuse rated at ? 7.5A? Try just replacing the fuse and covering the exposed(yes they are exposed!!) connections of the phone connector and see if that fixes it? Let's test for short to ground 1st? Remove E6. Connect the black to a good body ground ,ideally with an alligator clip and leave it there. Connect the red DMM probe to the brown conductor. That should be continuity ? Put E^ back in place -retest. Now , let's check for 12v at Red/ Green with the red DMM probe .Set DMM to DC volts- extreme left on your DMM. What happens? You should get 12v.Repeat with ignition on. Now let's check Green/Black and Yellow/black the same way. With these results you are ready to send Snap On gift coupons to Ahsai and beg for his help :-). Because until you fix this you can't put gas in the car to drive it ! Meanwhile consider replacing the notoriously fickle and unreliable ignition switch with an Audi one.(Search)

Quotes source post: 14098684

Yes Yes - both of them The moment a fuse touches the two leads (red box/green box) from my diagram it blows. All my tests were done without fuse E6 in place. Which brown conductor are you referring to? The connector in the red or green box or the one on the telephone 4pin connector? Which test do you want me to do (voltage or continuity)? I've done a tone test and voltage test with results in my post above this. As mentioned the instant a fuse blade touches both ends of that E6 connection it blows. Right now this shows 0 since I can't get a working fuse to sit in E6. The voltage tests I documented so far were with the meter set all the way to the left. I will check these and report back tonight. Well I can get gas into the car - it just takes 5 mins / gallon , but I am more than happy to see if Ahsai can help remotely before I break down and bring it to a local indy shop. I'd much rather fix on my own (for my own education in addition to saving money) if possible though. Just did this a few months ago due to failure of the OEM piece.

Did you tape over the telephone connector to stop the exposed contacts from shorting?

More data: Checking for 12V Un-switched: Green/Black - 0 Yellow/black - 0 Brown - 0 Switched Green/Black - 12.14V Yellow/black - fluctuated +/- 3mV Brown - 2.1mV

Quotes source post: 14099191

I was holding the connector in my hand.. I didn't see them arcing? I haven't taped over them yet since I am still using them to test.

If Brown (ground) to chassis ground is 2.1mV that is odd. It should be zero V. You won't see arcing. Squander some tape ? Obviously if you rub the exposed contact that is connected to Brown to chassis ground there will be a short circuit. Not good even at such low mVolts. We need to find where that brown conductor is picking up voltage.Ask others for a link to a wiring diagram from the FSM. BTW the 12v tests should really show more than 12v unless you have a tired old battery. Did you send the Snap on coupons to Ahsai ? I am jesting but he is one of the few who could take you quickly through the essential tests.

Quotes source post: 14099236

I'll get it taped up on my next round of tests. I'll re-test this again. It's actually a brand new battery. I'll double check the voltage at the battery. Not yet, but I'll contact him to see how much to send!

Quotes source post: 14099236

Ok - I retested with a different DMM and the weird 2.1mV and fluctuating on yellow/black is gone. Maybe I didn't have a good connection on the first test. I also taped up the connector, but am still getting a shorted fuse on E6 and the continuity test of the red box (from my fuse diagram) and ground still produces tone. Green box and ground produces 12.2V - I get 12.3V direct from battery. Green/black wire to ground produced 12V this time...

O.K. that seems more normal. Now we need to find the short. Definitely need the FSM Wiring diagram for that.Need to find all the components in the E6 circuit to test them. Or we can flail until a knowledgeable Sparky joins the conversation. The most likely component to be troublesome (Search) is the flap valve being prevented from operating because of fuel pipes obstructing it.You may have dislodged them when you replaced the reed valve? In previous link I gave: " 1) Fuse E6 that controls the filler tube flap is blown 2) The tubes on the fuel pump can block the flap from opening 3) The vent tube(s) are pinched (the TSB "Fuel Tank Hose Modification 5/99 2015" is for #2 or #3, but I can't find it) 4) But I also found a Pelican DIY saying to replace the fuel line vent valve that I've never seen mentioned once on Rennlist or anywhere else as being the culprit." Procedure for reed valve replacement: http://www.pelicanparts.com/techarti...Vent_Valve.htm

... disregard. Question answered in OP's first post...

Quotes source post: 14099272

It was unclear to me the actual procedure to check that and I couldn't find any DIYs for it. The TSB I found here: http://bethnrayndogs.com/car_docs/Po.../Grp2_5-99.pdf #4 is what I did already - not sure how that would impact #2 and #3 from the limited access I did under the fender. The pic from "Anthony" in the Pelican forums is actually mine with the blue tape after I did the re-install.

I can try to help. Get a 7.5A smart fuse from autozone or alike and plug it in the E6 slot. It should glow. Now trace back the steps you took to replace the valve and see if the wiring of that reed switch is inadvertantly pinched to ground. If you can disconnect the reed switch, disconnect it and see if the fuse light turns off. Fuse E6 supplies power only to two places - the reed switch and the phone plug red/green wire. The switch when closed supplies power to two more valves. Since you seem to have a short even with the reed switch not activated, the short may be in the reed switch or its wiring.

Brilliant.Thanks Ahsai. For more , Search for "Smart Glow LED indicating fuses" Here is the detail for visual learners(like me) You Tube useful tool for a wring harness defect You Tube

I broke down and brought the car to an indy shop. In their initial diagnosis I learned the part I replaced was defective, but they are still working on tracing the short. I'll report back when they find it. That tone tool idea is great. I have one of those that I used for telecom work.. good to see how I can re-use the tool for automotive wiring checks in the future.

Update: I misunderstood the defective part. The pic belows shows the 2 parts being replaced. fvbrByq.jpg The pic below this shows where my reed switch was part of the problem. For anyone coming upon this thread do yourself a favor and INSPECT this when swapping out the 996-201-143-01 Fuel Line Vent Valve . The Fuel Tank Vent Valve they were able to test as being defective. Downside is since I have a Carerra 4 the front end has to come down for them to get access to the gas tank to replace the part

Glad to read of a successful diagnosis. If you are pleased with the work by your Indie, you might publish their contact info here to help others looking for help in your area?

Quotes source post: 14112008

I've used them before and have been pleased (Air Oil Separator and fixing alarm issues): https://www.yelp.com/biz/fremont-for...repair-fremont 444 Mowry Ave Fremont, CA 94536 [phone removed] EuroCarTech.com They don't specialize in just PCars, but every time I've been there I've seen no less than 4 that were in for service.. They do have a lot of experience with them though. I was turned on to them by a friend.

Thanks for sharing.

Here's what my dead valve looked like after it came out: LJDT0Ck.jpg 0095MEN.jpg Suffice to say after 2k of labor I can pump gas like normal folks now...

Glad it worked out finally... Go for a nice long drive!

We have a 900 mile tour coming up so we will be getting in a lot of driving!

The defective part photo looks like it had a short and overheated badly. In theory the E6 fuse should have blown long before the part softened and bloated with heat ?

Quotes source post: 14126550

That's what the shop said too.. I'm not sure what happened...I remember looking at fuse E6 originally and it wasn't blown (way before I changed the original valve). I'm wondering if I had a defective fuse somehow...once it blew then it consistently blew though.

Quotes source post: 14111875

I'm trying to tackle this job for my C4 also. Do you remember what is entailed in the "front end has to come down to access the gas tank"? Do you mean the fender liner? Or literally the front suspension?

Quotes source post: 15781141

He had to take down the front axle. I think he said it was required for C4s.

Ok I�m assuming just the passenger side axle? Thanks for your help. I think this this will fix my problem.

Quotes source post: 15781254

Unfortunately, I don't recall if he just did one side. However, if you think you can reach up into the gas tank area doing that then it is probably correct.

Just a heads up for people who may be following the Fuse E6 part: I had problems fueling on my way to get other work done at my Indy. I had searched it on the web and found out about the fuse. He was sure it wasn't� the fuse though. It was. I had caused a brief short of one of the wires from the telephone circuit when connecting to it for my stereo install a week prior. New fuse use and I was able to fill the car. Unable Le to fill can be lots of causes that take more time or parts to address but the E6 fuse is the easiest and cheapest route if you are lucky.

Quotes source post: 13542929

I am having the same problem. Anyone know why this is happening? very frustrating.

Hello guys I hope some one will be able to help me. I have 911 - 996 model. For the last few years i also have problem with refueling and i also have engine light turned on. So few days ago i said i will try to solve this. I think i read EVERY forum about this problem now So... i checked everythink what i could find, charchoal canister vent valve, fuse E6 etc. And Everythink is fine. But i dont get that clicking sound when i try to push filler cap inside. Today i found out, if i put magnet by the reed switch (that short stick which is inside vent valve), then i hear clicking sound inside. So looks like everythink is working at my car, i just can not find out what is normaly trigering that switch? Because magnet trigers it, but if i just lift up that blockage inside the filler tube nothing happens. can any one help me ? Thank you

what a pain!! i have 986 and working on similar issues. Mine is more difficult starting after filling up. Requires about 10-15 cranks and me massaging the gas pedal fully pressed then release a couple of times... sounds like you either have a defective reed switch or poor connection to that reed switch that triggers the opening/closing of the valve to allow you to fuel up! $2,000 fix! nuts... in the past, i've ran wires from relays into the cabin of the 944 to a switch that can 'trip' the relay when I need it to run. fuel pump relay was the issue in this case... perhaps can run power to the reed switch to 'trick' it to make it work? only when you are fueling up?? so unnecessarily complicated!!