edc Posted June 14, 2023 Report Share Posted June 14, 2023 1 hour ago, ½cwt said: My point was that the humming from the TB could be transmitting through the bulkhead to seem as if it were coming from the DME. A bit tenuous I know. Before the engine start if the ignition is switched on you can what the TV and it's more of a higher pitch white noise kind of noise, then the clocks as the throttle plate spins through its action. Quote Link to comment Share on other sites More sharing options...
Rav Posted June 15, 2023 Author Report Share Posted June 15, 2023 Thanks friends. The humming - i finally caught it on my phone. Please see video here. https://youtube.com/shorts/bCwsZTOylrQ?feature=share Unscrewing the petrol tank filler cap stops the noise.... Quote Link to comment Share on other sites More sharing options...
edc Posted June 15, 2023 Report Share Posted June 15, 2023 Is it the honking noise? Quote Link to comment Share on other sites More sharing options...
Rav Posted June 15, 2023 Author Report Share Posted June 15, 2023 Sort of, but its not the horn. Did the youtube clip work? Quote Link to comment Share on other sites More sharing options...
iborguk Posted June 15, 2023 Report Share Posted June 15, 2023 Yes the YouTube clip worked. Tried swapping the petrol filer cap from another Boxster as a test ? Quote Link to comment Share on other sites More sharing options...
edc Posted June 15, 2023 Report Share Posted June 15, 2023 Put your ear by the filler cap, is it that? If so as above swap cap or replace seal. It's almost like a wind instrument so it's air passing through something. Quote Link to comment Share on other sites More sharing options...
Rav Posted June 16, 2023 Author Report Share Posted June 16, 2023 The filler cap has a lot of air either escaping or being drawn in. Should this be an air tight seal? Quote Link to comment Share on other sites More sharing options...
Menoporsche Posted June 16, 2023 Report Share Posted June 16, 2023 Needs a vent somewhere or it will cause a vacuum. Not sure if it is supposed to be at the cap though. Quote Link to comment Share on other sites More sharing options...
½cwt Posted June 16, 2023 Report Share Posted June 16, 2023 3 minutes ago, Menoporsche said: Needs a vent somewhere or it will cause a vacuum. Not sure if it is supposed to be at the cap though. Shouldn't be through the filler cap. Isn't assisting breathing what the AOS does...? Quote Link to comment Share on other sites More sharing options...
map Posted June 16, 2023 Report Share Posted June 16, 2023 21 minutes ago, Menoporsche said: Needs a vent somewhere or it will cause a vacuum. Not sure if it is supposed to be at the cap though. 14 minutes ago, ½cwt said: Shouldn't be through the filler cap. Isn't assisting breathing what the AOS does...? Fuel tank has a breather - to my knowledge the fuel cap should be “sealed” - think of the air rush when you take the cap off a nearly empty tank. Vaguely remember someone having problems like this which were eased if not cured with a cap change as mentioned previously. AOS is a different subsystem - Air Oil Separator - nothing to do with fuelling. The AOS takes excess air pressure which carries oil mist from the engine’s internals. This air/oil mist flows into a chamber which separates most of the oil from the pressurised airflow. The oil is returned to the oil system and the air is fed into the intake plenum. That air - with some oil residue - is then put through the combustion process. When the AOS fails you get the tell tale smoke signals - you can also find some oil in the plenum. Quote Link to comment Share on other sites More sharing options...
½cwt Posted June 16, 2023 Report Share Posted June 16, 2023 34 minutes ago, map said: Fuel tank has a breather - to my knowledge the fuel cap should be “sealed” - think of the air rush when you take the cap off a nearly empty tank. Vaguely remember someone having problems like this which were eased if not cured with a cap change as mentioned previously. AOS is a different subsystem - Air Oil Separator - nothing to do with fuelling. The AOS takes excess air pressure which carries oil mist from the engine’s internals. This air/oil mist flows into a chamber which separates most of the oil from the pressurised airflow. The oil is returned to the oil system and the air is fed into the intake plenum. That air - with some oil residue - is then put through the combustion process. When the AOS fails you get the tell tale smoke signals - you can also find some oil in the plenum. Sorry, mis-interpreted oil filler for fuel filler... Quote Link to comment Share on other sites More sharing options...
Rav Posted June 16, 2023 Author Report Share Posted June 16, 2023 I have ordered a new fuel filler cap from Design 911. I will report back with updates. Quote Link to comment Share on other sites More sharing options...
the baron Posted June 17, 2023 Report Share Posted June 17, 2023 (edited) I had this issue with my 996, turned out to be fuel filler vent, I bought the part from my OPC, this could be why your smelling petrol too and could cause your starting issues maybe, here’s a video on how to swap. It took me about an hour to swap,out Edited June 17, 2023 by the baron Quote Link to comment Share on other sites More sharing options...
Rav Posted June 29, 2023 Author Report Share Posted June 29, 2023 Thanks @the baron. I bought a new fuel filler cap and fitted this. The harmonica type sounds is still there, but much less obvious. The next part to change will be the fuel filler vent. I am chasing issues. Quote Link to comment Share on other sites More sharing options...
The Caped Crusader Posted June 30, 2023 Report Share Posted June 30, 2023 I watched your video and immediately thought that the fuel cap was very loose when you unscrewed it. Also, when you re tighten at the end of the video, I don't hear any clicks. Mine (987) clicks upon re-tightening. Quote Link to comment Share on other sites More sharing options...
Menoporsche Posted June 30, 2023 Report Share Posted June 30, 2023 Holy Broken Ratchet Mechanism! 1 Quote Link to comment Share on other sites More sharing options...
Rav Posted July 4, 2023 Author Report Share Posted July 4, 2023 Pay day came, so i bought a new Fuel tank bleeder valve from Design 911. I will fit it when it arrives and let you know if my issues are resolved..... Quote Link to comment Share on other sites More sharing options...
the baron Posted July 8, 2023 Report Share Posted July 8, 2023 On 7/4/2023 at 9:25 PM, Rav said: Pay day came, so i bought a new Fuel tank bleeder valve from Design 911. I will fit it when it arrives and let you know if my issues are resolved..... I did this on my 996, PITA job allow about 2hrs happy to help if you want to scoot over one evening. It’s all very doable, the video I posted above is what I used to do mine 1 Quote Link to comment Share on other sites More sharing options...
the baron Posted July 8, 2023 Report Share Posted July 8, 2023 On 6/30/2023 at 10:59 AM, The Caped Crusader said: I watched your video and immediately thought that the fuel cap was very loose when you unscrewed it. Also, when you re tighten at the end of the video, I don't hear any clicks. Mine (987) clicks upon re-tightening. The 986 caps just tighten to a stop no clicks Quote Link to comment Share on other sites More sharing options...
Rav Posted July 13, 2023 Author Report Share Posted July 13, 2023 I managed to sneak out between meetings today, whilst working from home and changed the fuel tank bleeder valve. Thanks @the baron for the link to the video which i followed and managed to get done in a couple of hours due to only having 30min slots. I have not tried the car yet. I will keep you all updated. 1 Quote Link to comment Share on other sites More sharing options...
Rav Posted July 14, 2023 Author Report Share Posted July 14, 2023 and after all that. The car still is making humming noises.... A lot less, but its still present. Oddly, I feel that the car is running better - breathing better, more agile. Is this possible? I have also noticed a new oil leak. Is it time for a Tesla model S? Quote Link to comment Share on other sites More sharing options...
½cwt Posted July 14, 2023 Report Share Posted July 14, 2023 You're not having much fun... May be a damage hose not just a particular device? Where is the oil leak from? The only common one is a rear main seal so from the back of the engine. Tesla 😱 Quote Link to comment Share on other sites More sharing options...
Menoporsche Posted July 14, 2023 Report Share Posted July 14, 2023 1 hour ago, Rav said: Is it time for a Tesla model S? Very fast, very reliable, after the hyperspeed novelty cools - no fun whatsoever. 1 Quote Link to comment Share on other sites More sharing options...
The Caped Crusader Posted July 14, 2023 Report Share Posted July 14, 2023 4 hours ago, Rav said: and after all that. The car still is making humming noises.... A lot less, but its still present. Oddly, I feel that the car is running better - breathing better, more agile. Is this possible? I have also noticed a new oil leak. Is it time for a Tesla model S? I think it's time to bite the bullet and take it to a trusted independent for a diagnosis. 1 Quote Link to comment Share on other sites More sharing options...
Rav Posted July 29, 2023 Author Report Share Posted July 29, 2023 Thanks for the continued support friends. I took the care to LAP911 in Highworth. Luke checked over the car. He heard the harmonica sound. He suggested a new fuel filter and fuel pump, but also advised that it might be a small valve at the bottom of the filler neck. £350 inc vat to fix. I might just live with it. The oil leak was a quick fix, some tensioner washer. While there, I was also told that I need new brake discs and pads, Spark plug tubes, brake lines, Front suspension springs and shocks. I plan to get these done over the autumn. Quote Link to comment Share on other sites More sharing options...
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