clickman

OP here. To close the loop on this, I gave up and took it to an indy. His initial reaction was that the common problem was the valve at the top of the filler neck. He found out that wasn't true, and started diving in more deeply. It turned out to be the evap canister.

This is for a 986, but the 996 front end is identical, so...

I'm having the all-too-common problem of the tank not filling to the top. Constant clicking off of the pump nozzle. Filling the tank with the fuel handle at every angle of 360 degrees didn't work. Pushing the little tab that's normally depressed by the cap didn't work (although the tab is looking kinda worn). This has been going on for a few years, and I'd talked myself into thinking this is just a Porsche thing, but now I want it fixed. It did work, so there's something wrong. No CEL/MIL. No difficulty starting after filling.

After a ton of research, it finally sunk into my pea brain that there are two systems: the main Evaporative Emission Control System (EVAP) that captures stray fuel vapors while operating and sitting, and the intermingled Onboard Refueling Vapor Recovery system (ORVR). It's the ORVR that vents the tank during fueling.

Pushing the fueling nozzle into the filler hole moves a flap that activates a reed switch on the filler pipe. This switches operation from EVAP to ORVR, activating two valves:

- the ORVR valve on top of the fuel tank

- the "fresh air" valve located in the front right wheel arch

With those two valves open the tank can vent to atmosphere during fueling, through the carbon canister.

So why is mine not working?

Some people have a problem with Fuse E6, which powers the ORVR system (grounds out from a telephone connector in the center console). Mine is fine. So next is the two valves. I pulled off the wheel liner to get to the valve in the wheel arch. I can hear and feel it activating. Then I pulled out the battery and the lid under it, getting to the fuel tank.  The ORVR valve there I could also feel activating.

Assuming the valves are actually doing something, that leaves the carbon canister and the interconnecting hoses/pipes.  The atmospheric line from the fuel cap area seems like a potential culprit and it's subject to collecting debris.  My question: how is the line disconnected from the valve plenum without damaging it? See pic

Assuming the lines aren't plugged, and the carbon canister is plugged, wouldn't this set off a CEL/MIL?  It is part of the EVAP system as well.

Then there are a couple of potential mechanical issues not related to ORVR air flow. The spitback valve at the end of the filler tube could be sticking or blocked. But woudn't the tank be difficult to fill in its entirety, rather than just near the top? Then there is the issue with the flexible fuel hoses inside tank obstructing the spitback valve. Porsche issued a TSB: Fuel Tank Hose Modification 5/99 2015 or 03/99 2015 (different numbers from different forums) - tie fuel tank hoses out of the way of filler pipe flap. I couldn't find the TSB. Is it applicable to cars past 1999? Does it make sense that like in my case it started about 15 years after the car hit the road?  Can this be determined by putting a scope down the filler pipe or would the spitback valve get in the way? I did try this but got chicken and stopped when the scope got to a section of the pipe that looked corrugated.

So my questions, for those of you kind enough to help:

1. How is the pipeline disconnected from the valve plenum without damaging it?

2. Wouldn't a plugged carbon canister set off a CEL/MIL?

3. Does anyone have the TSB?  What years is it applicable to? Can this happen many years after the car is sold? 

4. Have I missed anything as far as potential failure mechanisms or is there any other advice?

Thanks!

I'm having the all-too-common problem of the tank not filling to the top. Constant clicking off of the pump nozzle. Filling the tank with the fuel handle at every angle of 360 degrees didn't work. Pushing the little tab that's normally depressed by the cap didn't work (although the tab is looking kinda worn). This has been going on for a few years, and I'd talked myself into thinking this is just a Porsche thing, but now I want it fixed. It did work, so there's something wrong. No CEL/MIL. No difficulty starting after filling.

After a ton of research, it finally sunk into my pea brain that there are two systems: the main Evaporative Emission Control System (EVAP) that captures stray fuel vapors while operating and sitting, and the intermingled Onboard Refueling Vapor Recovery system (ORVR). It's the ORVR that vents the tank during fueling.

Pushing the fueling nozzle into the filler hole moves a flap that activates a reed switch on the filler pipe. This switches operation from EVAP to ORVR, activating two valves:

- the ORVR valve on top of the fuel tank

- the "fresh air" valve located in the front right wheel arch

With those two valves open the tank can vent to atmosphere during fueling, through the carbon canister.

So why is mine not working?

Some people have a problem with Fuse E6, which powers the ORVR system (grounds out from a telephone connector in the center console). Mine is fine. So next is the two valves. I pulled off the wheel liner to get to the valve in the wheel arch. I can hear and feel it activating. Then I pulled out the battery and the lid under it, getting to the fuel tank.  The ORVR valve there I could also feel activating.

Assuming the valves are actually doing something, that leaves the carbon canister and the interconnecting hoses/pipes.  The atmospheric line from the fuel cap area seems like a potential culprit and it's subject to collecting debris.  My question: how is the line disconnected from the valve plenum without damaging it? See pic

Assuming the lines aren't plugged, and the carbon canister is plugged, wouldn't this set off a CEL/MIL?  It is part of the EVAP system as well.

Then there are a couple of potential mechanical issues not related to ORVR air flow. The spitback valve at the end of the filler tube could be sticking or blocked. But woudn't the tank be difficult to fill in its entirety, rather than just near the top? Then there is the issue with the flexible fuel hoses inside tank obstructing the spitback valve. Porsche issued a TSB: Fuel Tank Hose Modification 5/99 2015 or 03/99 2015 (different numbers from different forums) - tie fuel tank hoses out of the way of filler pipe flap. I couldn't find the TSB. Is it applicable to cars past 1999? Does it make sense that like in my case it started about 15 years after the car hit the road?  Can this be determined by putting a scope down the filler pipe or would the spitback valve get in the way? I did try this but got chicken and stopped when the scope got to a section of the pipe that looked corrugated.

So my questions, for those of you kind enough to help:

1. How is the pipeline disconnected from the valve plenum without damaging it?

2. Wouldn't a plugged carbon canister set off a CEL/MIL?

3. Does anyone have the TSB?  What years is it applicable to? Can this happen many years after the car is sold? 

4. Have I missed anything as far as potential failure mechanisms or is there any other advice?

Thanks!

There's a fellow on 986forum.com that has designed and made commercial projectors for non-Lit Boxsters.  I installed them myself (total cost less than $400), but if you don't want to get into the hassle of using the oven to break them apart, there's a guy on the forum that will do them for you.  He's done a lot of them and for a reasonable price.  I have to say that, short of the 98x short shifter, this is the best mod I've ever done.  It makes a HUGE difference to the front of the car.

I can't figure out how to post a weblink on this forum, so go to the DIY Project Guides section and look for the thread called "Porsche Headlight Retrofit (from CAD, prototyping to finish)".

I just found out about the much lower torque requirements for the LN Eng magnetic drain plug and realize I may have stripped the threads on the last oil change before winter bedtime.

I could feel the torque wrench start to slip, stopped right away, but did continue putting oil in the engine. No leaks so far. But now I'm concerned the threads in the pan have been stripped, rather than the bolt. There's a pan available from an 2004 2.7. Any reason why that wouldn't fit on a 2001?

I put the original switch back in and the a/c and blower work.

Good news, bad news. Good news is I know what the problem is and can now fix it. Bad news is I wasted time and money on a bad product. Stay away from this Meyle switch!

I was having the usual key insertion / removal problems, but the A/C was working fine.

I bought a Meyle switch for cheap, replaced the switch, and now the A/C and blower don't work at all. And the fuses are fine.

Could this be the fault of the cheap replacement switch?

Are the Audi switches really better quality, or do they have them made in China too?

Right, JFP, that would be the cost if I'd ordered one with all the rest of my parts from Suncoast. With shipping etc it's a lot higher for one item, and my local stealer charges around $75...

Anyways, I get the message.

Stupidest idea ever? Or no big deal?

Getting the car up and down off the jackstands is a PITA.

I drained the cooling system as part of some projects I'm doing. So it's on the jackstands now.

But as I don't know what kind of coolant was in the car, I'm going to flush it with water, which means running the car. And then draining the system completely again before putting the final fill of 50/50 coolant in.

I'm in the process of changing my water pump, upgrading to the LN Eng low temp thermostat, upgrading to the "S" oil cooler, and replacing my motor mount.

I just realized that I didn't note the direction of the serpentine belt when I pulled it off, after having read somewhere that I should put it back on the way I took it off.

Is that really a big deal? Or could it come apart a lot faster?

This belt only has about 15,000 km (10,000 miles) on it and still looks good.

I think I might also change out my oil cooler for the "S" model cooler at the same time.

I have an '01 base.

Do a search. This subject has been covered many times here and on 986forum. I installed the stock 9x7 SHORT shifter in my '01, and love it. Many others have found the stock 9x7 standard shifter to be to their liking. The regular shifter is a lot cheaper than the short shifter. The advantage with both of them is that the entire shift tower is replaced, rather than rebuilding your existing tower.

In order of shift distance, shortest to longest:

Porsche / B&M short shifter for 986 35% reduction

Agency Power 35% reduction

Schnell 30% reduction

Porsche 987/997 short shifter Part # 997-424-983-00 25% reduction

Evo Swift Shift 20% reduction

Porsche 987/997 standard shifter Part # 997-424-010-00 15% reduction

This is also the order of notchiness, most notchy first. (except for 9x7 short shifter)

Did you look at the link I posted? It's the whole top including frame.

I doubt the canvas alone from the 03 will fit on the 01 frame as there are a different number of support bows - 3 prior to 2003 and 4 after.

An 03 or 04 top is a direct bolt-on for 01. I'd love to do that when my rear window goes.

http://986forum.com/forums/showthread.php?t=20414&highlight=top

I probably won't replace mine with Ns when my Contis wear out.

IIRC, N-rating simply means that Porsche has tested the car with the tires on it, presumably in difficult driving conditions. My pessimistic little brain tells me that there's probably also $ involved.

I just did mine today. Use pipe tape fron home depot and wrapped with duct tape....wrked great. I only drimeled off the very top of the cap and really didn't need to seal it because the cap slid into the sleeve and sealed itself. One thing...took 5 hours, if had to do it again, 3 tops. I really don't lan on doing it again...it was hot in Fla and no fun....but it's done....99% of the foam was gone

Did you use the standard grey duct tape? That stuff will dry out quickly and get brittle and fall apart.

They should check the IMS to see if the seal is leaking and that the end bolts are the newer self encapsulated bolts. If it is not leaking it is best to leave it alone (IMHO).

Interesting. The common opinion now seems to be that if you've got the tranny out, do the clutch, RMS and IMS bearing. What's your thinking about the quasi-hysteria around the failing IMS bearing that I've been seeing for the last year?

For the button replacement, check out Kendo's posting:

http://986forum.com/forums/showthread.php?t=18203&page=2&pp=20

Worked for me.

What's happening, masterbm? All done and back on the road?

Keep it coming, masterbm. This sounds like what I would go thru if I was to try this project. I'm livin' it with ya!

But I really think you shoulda done the IMS while you were in there...

Some interesting reading:

http://986forum.com/forums/showthread.php?t=26499

Glass window top on 986 was only 2003 and 2004

On the radio question, there is a little fuse in the back of the radio unit itself.

Yeah, I've already got the radio pulled and the fuse out. Unfortunately the fusible part isn't visible and I don't have a continuity checker. Now I need to figure out where to get a replacement! (Porsche part number 996-blah-blah $322.99 ;) )

I just wonder if it's normal for the voltage to go down like that...