Weird whistle and ignition switch delay..

So - I have two issues at once, and for a change, they're not related to each other at all (I think..) - Weird whistle noise - I believe from the engine area. I haven't tracked down what's causing it (has anyone had this and tracked it down..) It mostly happens when the car has been driven some distance and then shut off. Most noticeable when I stop it in the garage. It sounds like the noise used in WW-II movies for a falling bomb. Falling bomb sound effect | Sound Effects | Royalty Free | HookSounds I also noticed last night, I can faintly hear it (I'm a big deaf) just when the engine is running - but then it's a constant whistle noise. My WAG - one of the damn accordion-plastic hoses under the hood has decided its time has come, and it's probably on the intake side downstream from the throttle body. Anyone? - Ignition lock, progressive failure. I have been having issues with the replacement Chinese AliExpress headunit not shutting off immediately with the key out. Formerly it always shut down when the key was removed from the ignition. First, it took 30 seconds, then around 3 minutes, and last night 13 minutes - 20 seconds. I also don't always get cranking when I turn the key to start, or sometimes the cranking is delayed. And the click noise (key getting locked in the ignition switch) is late to happen on key removal and happens only when the key is fully inserted on key insertion. I did some research on the ignition lock assembly, and it's really a glorified "start" button. The thing would work with an uncut key as long as the immobilizer recognized the RFID chip in the key. It doesn't actually have tumblers or sliding physical locking going on involving a cut key. What it does is - when the key is inserted the immobilizer looks for a recognized key (reads the chip) and if it finds one it releases a locking solenoid that's used to keep the key barrel from turning and locks the key in the lock. That's why the ignition lock assembly needs no programming, and no rekeying of the cylinder when it's replaced. That puzzled me for a bit (reading swap-out reports here and on other websites) - but it makes sense when you think about Porsche wanting to retain tradition with their awkward left-side "racing" key traditional layout. I suspect it's a German thing. So - has anyone had these failures? Somehow I suspect the car will be taking a trip to Provost Motorsports, neither of these sounds like fun jobs (the ignition lock is apparently well protected by obstacles placed in the path of its removal, and the hose experience - well - my back won't stand up to working in the engine compartment for very long at all..) and Max at Provost is a good guy.. so have to make a phone call...

I would guess the whistling is from a vacuum leak. Maybe try a length of rubber hose to pinpoint, one end in your ear, the other poking around the engine bay. Those plastic lines that lead to the AOS are very fragile, that would be my starting point. For the other problem, I'd bet on the need to replace the ignition switch. I haven't done it, but I've read that it is pretty easy to replace. Good luck!

I have an appointment at Provost with Max to replace the switch on August 16th. I just hope the old one holds up until then (or I'd be relegated to driving the Cayenne..) I also talked with Max about the whistle - I realized about when this started up was around when I replaced the fuel cap.. I mentioned this to Max he said to try putting the old one back on. I'll be doing that tomorrow. He's had them whistling along with the dropping bomb noise. The one I bought (via eBay) looked just like the original, but I'm guessing it perhaps has a partly restricted vent for the fuel tank, so the continuous whistle I hear when is the continuous vacuum the fuel pump and the leak detection system pull on the fuel tank, and the dropping bomb noise is caused by the relief of the remaining vacuum in the tank when the two systems shut down. Gotta love a mechanic who helps you avoid needing his services! I'll give the old cap a try tomorrow, I just replaced it because the tether broke, and the replacement I got was less than the cost of the tether and the push-pin from Porsche . Oh well - the new tether can still be used, so if it was being caused by the new cap, I still come out ahead.

That's interesting - I would have thought if the fuel cap was leaking pressure, a CEL would be thrown. I'll be interested to see how this plays out.

Gosh, Don - You've had quite a few headaches lately! Hope things smooth out. 1) Whistle - Makes sense per fuel cap! I bet that's the culprit. [EDIT: The cap may not be able to be reused and I intentionally ordered a new cap just for the tether.] Thankfully, the cap is very inexpensive. Sounds like a pressure situation that's venting out and whistling. But both the cap and fuel tank is in front and that's not from the engine bay. If that doesn't work, I'd want to watch the engine run (inspection bay) with sound. 2) Whatever you do, especially as you've been doing a ton of tinkering with the radio recently, I'd strongly suggest you do a serious battery recharge first as that's free of charge -- and then see if that effects the delay times. Hang in there and let us know how you get on.

Seth, and @racergreg - 1 - I looked at the new and old caps - identical down to the casting marks on the plastic and codes embossed into the plastic. But I can't see how to get the tether off the cap.. I didn't spend a lot of time though. As far as the location, I usually hear it in my garage - with the windows up - and I'm a bit deaf in my left ear and not great in the right, so location was strictly a guess. 2 - I'd agree but I have taken the car out on long enough drives that the battery should be fine. I've measured the standing voltage on it and it's been > 12.5V and usually a bit above 12.6V which is 100% charged. I don't think that's the issue.. but research continues. It was actually too darn hot to play with it today - a bit above 96F, feel-like temp of 106F. Cooled down to 87F along the ocean, but no place to play with the car there.

Hey Don, 1) Come to think of it, I'm no pretty sure I had had ordered a replacement cap altogether -- as my original cap had a torn tether. So I doubt it's replaceable. [I've already edited my previous response.] Again. replacements are inexpensive and may be a super-quick way to check. 2) I doubt the battery is the issue, but the vintage VW file cabinet in my brain had something to do with a slow ignition and not getting enough juice to really turn the starter. I sometimes see something similar in our more modern Vespas...where I have to step on the kickstarter a few times just to move the engine a bit -- which decreases the internal friction -- and then it starts electrically. Again, I doubt any of this is the issue, but it's inexpensive stuff to try. Hope you're keeping cool down on the shore as best as you can. (Meanwhile, I'm guessing you can't wait for the summer tourists to go home!!! LOL.)

1 - We'll find out. I swapped the old one back in (no tether, but not an issue - we don't pump our own gas in NJ. And the guys that do just figured they'd let it dangle down the fender. They were clueless about the hook on the gas-door..) 2 - I don't believe this is battery caused. I've checked the battery voltage a number of times, and it's in the 90-100% charged range. It was 83F this morning on Ocean Ave (which strangely - runs along the ocean..) and 97F a few blocks inland. Usually late afternoon we get a wind reversal where the inland has heated up enough to cause an upward flow, drawing air in from the cooler air over the ocean. So the wind becomes from the east or south-east and temps drop for a mile or so inland.

Not the fuel cap.. ughhhh... that means going deeper. That means Max at Provost will make more money. I have an appointment for the ignition switch, have to see if he can do any quick diagnostics while I'm there.

Don, it’s been awhile, but if I remember correctly I replaced a fuel cap on a previous 996 and ran into the same issue with the tether. I used a pair of diagonal cutters and nipped off the end at the cap, slid the new cap onto the tether and using a small butane lighter, softened the end of the plastic tether then wet my finger, gritted my teeth and squeezed and rolled it into a little round ball which was greater than the diameter of the hole it was inserted into. Worked like it was designed for that.

Strangely - the whistle disappeared. It seemed to coincide with a fresh tank of fuel.. I'm still above half a tank, we'll see what happens as the level goes down. As for the ignition switch mystery - this continues. My granddaughter (visiting, 4 years old) was sitting in the car and she tried the window switches. MUCH to my surprise - the windows moved.. No key in the ignition for over 12 hours, but some circuit is on that shouldn't be. I can only attribute that to the switch which may also be part of the weird behavior of shutdown on the Chinese headunit (not shutting down on key removal.) I have an appointment to get the switch replaced on 8/16 - we'll see how it behaves after that..