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johnmh

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Everything posted by johnmh

  1. johnmh
    I think the one on top of the tank is only a pressure sensor. From what I can see in the Bentley manual, the actual valve that opens when you fill the car is somewhere behind the carbon canister inside the right fender. Will explore further, but if this does not fix it, I am going to weld the fuel filler door shut, drill a big hole in the hood and the tank and put a racing fuel cap in the middle of the hood.
  2. johnmh
    Does anyone know how to access the fuel tank vent valve Pierburg 996.605.203.01?, I think it is on top of the fuel tank, but must the tank be removed (how?) to access it? It seems to be the only part I have not replaced on the way to solving my fuel fill issue. A picture may be found at: https://www.carid.com/pierburg/carbon-canister-fuel-tank-vapor-valve-mpn-996-605-203-01.html Thanks for any suggestions.
  3. johnmh
    Just to update, so far I have replaced the vent valve, gas cap and sensor. I have checked the E6 fuse. Still no relief, the car continues to spit fuel when I try to fill it. My thoughts now go to the electric vent valve on top of the tank. With the plug connector to that electric valve disconnected (and the battery connected to the car via jumper cables) i checked for voltage with the gas cap open and a large steel rod in the filler neck (to replicate the gas filler nozzle for the purpose of the sensor). No voltage comes from any of the three wires (which should be needed to open the valve on top of the tank, no?) As mentioned, the E6 fuse seems fine. All I can think of is to check for continuity between the fuse box and the plug. Any other ideas? No obvious rodent issues seem to exist.
  4. johnmh
    Does it not need to be near something like a gas nozzle (i.e. steel) to close the circuit and open the vent? When it is just sitting on the (wooden) table, the resistance is infinite. Only when I press it against a magnet does the resistance approach zero. I would have thought there was a magnet in it, i.e. when it senses the pump nozzle it closes the circuit and allows air to leave the tank (via the charcoal canister). I am beginning to understand why they redesigned this system on the 997. Only Porsche could so overengineer what is effectively a hole to pour a liquid through.
  5. johnmh
    So, the small magnetic sensor was placed back into the groove in the plastic part of the vent valve which attaches to the fuel filler pipe. Next trip to the gas station - no joy. The fuel spat back out as usual. This morning I unplugged the magnetic sensor and checked it with an ohmmeter - full resistance. I then pushed a large diameter socket extension into the filler neck (to approximate a fuel filler nozzle). Full resistance. I then pulled the sensor from the car and bench tested it by placing it on a large chunk of steel. Full resistance. Finally, I placed a magnet on it - finally, the resistance dropped to near zero. Am I bench testing it properly? Is it supposed to detect the presence of a steel gas station filler nozzle when placed into the fuel tank filler pipe? So far I have replaced the vent valve and the gas cap without luck. I have also checked the fittings at the top of the tank. Besides the vent for the charcoal canister, I am running out of options. Thank for the help so far, I would not have diagnosed the issue to this extent without help from this site.
  6. johnmh
    Will have a chance to look at it on Thursday after work. Fingers crossed.
  7. johnmh
    Ah! That little cylindrical thingy connects to the gas tank vacuum switch where it pokes out of the vent valve. Mine is not connected, and was not connected when I examined it before I replaced it. That might be it. Thanks! Something to try this weekend.
  8. johnmh
    Where would it be? (It does not look familiar). I open the fuel cap, look in, I see a metal disk with a hole covered with a flap on a spring. Not much else. When I fill it with a funnel and a gas can, it fills fine (albeit slowly). Thanks.
  9. johnmh
    I know this has been covered, but all the posts seem to start with a direction to 'read the posts', which is less than helpful. I have the apparently common problem whereby I need to use a teaspoon when I fill my '01 996, or it will petulantly spit its breakfast all over my shoes. The car has done this since I brought it back to life last fall. I have replaced the fuel line vent valve, checked the mythical E6 fuse (not sure what it does or what it powers, but mine seems the picture of health). I cleaned a ground spade connector which connects to the alloy bracket which secures the fuel line vent valve to the fuller neck. I have also pulled the battery and tank cover plate (when I installed a new fuel pump earlier this week), all the hoses seem good (no mice) and properly connected with a 'click'. From what I can tell, the fuel tank vents through a small diameter hose which connects to the vent valve via a canister. It appears that the air displaced by incoming fuel has nowhere to go; something in this Rube Goldberg Porsche design has gone awry, or never worked from inception. Apparently there is a factory bulletin on this issue? Is there a number / date for it, or is there an online source for these? The fuel line vent valve is a purely mechanical thing? It seems to have no place to plug any wire in to it, so I am not sure how it decides to open or close. Thanks to all for any insight which you can share.
  10. johnmh
    Tank is clean inside, except for a few tiny, broken zip ties. Screen on the bottom of the tank is discolored, but not plugged. This may be a good reason to keep the tank topped up. Comparatively speaking, this has been easy to do (unless I damage the fuel level sender when I reinstall it). I suspect as the entire car was a study in deferred maintenance, the fuel filter may also have had something to do with its demise. Yes, my car was sold new in Georgia, lived in Texas for a while, was exported to Canada, and then brought to Dubai by a Canadian who moved here. It's not done traveling yet, I eventually want to ship it to my place in Italy where it will be holiday daily driver. If I do that I should take it for a road trip to Stuttgart to close the circle.
  11. johnmh
    Scary stuff, but I am not certain there would be enough oxygen in the tank to actually catch fire.
  12. johnmh
    Fuel pump is toast. No errors displayed on Durametric. No fuel pressure. Fuse ok, jumped pump relay made no difference. I drained the tank and pulled the pump. Wow. All insulation burned off one wire. Wire itself dangling free, not connected to pump as the pump electrode melted through and detached. All plastic near the electrode melted to a black crisp on the top of the pump body. Amazing this much current could do this damage without burning through a 30A fuse or a relay. No detritus in the tank, but the rubber seal around the top had turned to black goo. How did this thing not torch itself? I was very lucky. Will post pictures later.
  13. johnmh
    I added fuel to the tank and checked the 30A fuse (neither were the issue). I will use the Duramteric tomorrow and measure fuel pressure, but just so I understand where all the relevant electrical components are - there is one fuel pump relay on the board under the dash above the fuse box, and a second one in the back of the car (underneath the convertible top tray)?
  14. johnmh
    Got the car back and turned the engine over. Tach needle moves up ever so slightly. Perhaps the CPS is ok. My order from Pelican will only arrive early next week, so plenty of time for diagnostics this weekend.
  15. johnmh
    Thanks for the suggestions, I get the car back tomorrow (it was in having the convertible top fixed) so I can check that then. Is the 60 sec / off for 10 sec necessary to generate error codes? Yes, I have a durametric scanner. Do the fuel pressure regulators fail on these cars?
  16. johnmh
    Interesting, so the CPS signal dictates spark timing as well as sending a signal to the relay which feeds power to the fuel pump? Is there not a cam position sensor which plays a role in spark timing as well? FWIW, I was wrong about the Testarossa, the tachometric relay only permits the fuel pumps to get power, the spark timing is established by a combination of two distributors and a Marelli ECU which sets advance. Out of an abundance of caution I added a CPS to my Pelican order of a pump, a relay and a 30A fuse. If you replace everything, it must work, no? Unless it is out of gas....
  17. johnmh
    The car will turn over, catch on a cylinder or two, but not actually run. To my mind, that may rule out spark, but not fuel. So the crank position sensor actually needs to deliver a signal before the fuel pump will switch on (a typical safety feature)? My Testarossa uses a tachometric relay which shuts the fuel pumps off when the car is not running, in order to prevent the fuel pumps from running after an accident which stops the engine from running. The thing is, with a bad tachometric relay, the TR will not even catch on a single cylinder, as there is no signal to tell it when to spark. Would a failed crank position sensor on a 996 also result in no spark, as the CPS needs to tell the engine when to spark?
  18. johnmh
    Awesome. Thanks. Will check the fuse and relay first. And the fuel level in the tank...
  19. johnmh
    Thanks. I have a Beta pressure tester with sufficient fitting to adapt it, but where do you plug it in?
  20. johnmh
    Car is a US spec 2001 C2 Cabrio 6 speed, 78,000 miles. Sat for a year before I bought it as a project car. Since buying, it has had a major engine out, IMS, cam chain buffers, crank seal, coils, plugs, water pump, hoses, fuel filter, clutch, AOS, etc., etc., etc.... Car has been driven about 1000 miles since I finished the engine out, it drives flawlessly. Until today. Car was driven, parked for an hour and then would not start. It cranks, stumbles a few time (getting spark?) but will not catch. Warm or cold does not matter. Fuel level is low(ish), just under 1/4 full. One strange, perhaps unrelated issue is the difficulty in filling the tank at a service station. The station's gas pump will shut off (and spit fuel on my shoes) unless I fill it really slowly. Weird, is displaced air not escaping somehow? In any event, I am aware that fuel pumps fail, old relays wear out and the 30 amp fuse may even blow. I also understand that my Durametric will not signal a fuel pump error if there is an issue? Does this sound like a fuel issue? Any idea if the problem when filling the fuel tank may be related? Anyone else have fuel filling issues? As a precaution (and because I need to order this stuff via the web and pay shipping) I may just replace the pump, relay and fuse all in one go. Thanks for any ideas in advance. Car ran great for the first 500
  21. johnmh
    Fixed. Bad ballast. Finally got this car registered and am driving it. For a $6700 Porsche (plus $6k in new parts) this thing is awesome fun. Next issues are a/c, convertible top and a few dents.
  22. johnmh
    As an update the indoor lights now fade a few moments after shutting the door (good!). But the odometer continues to display the mileage for a long time. If it matters, the car is not locked and I had just turned on (and off) the headlights. Is there a microswitch which would cause this fault? Weird that it would 'half' fix itself.
  23. johnmh
    Thanks. I always wondered why that feature existed (now I know). I figured that all the auto lock might achieve would be to get me killed if I am ever incapacitated in a burning car (which might be more likely than a robbery). In any event I may put a timer on the light and see how long it lasts (or if it ever goes out). One by one, the secrets of the 996 are slowly being revealed to me.
  24. johnmh
    Yes, all lights and instruments go off when I lock the car with the key remote (I am outside of the car at that point).The door lights also go off when I start the car. How long should they stay on once I exit an unlocked car? On mine 5 minutes later the lights inside the doors are on (and even getting hot). I am not sure about the passenger doors, will check. The doors on my 2001 car (which is U.S. spec) do not lock themselves when I drive off. I always thought that the stupidest feature on any car. Thanks for the idea of the timer (I will also consider the microswitches in the door).
  25. johnmh
    Not at first, after the ignition switch replacement it was initially fine. FWIW, I chose the more expensive switch. I may have to check it again.
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