Car intermittently will not start up from ignition.

Hi All, ..... 2009 987.2 S manual. I have noticed lately that the car at times will not start with the key. I do the obvious, foot on the brake, turn the key...nothing I repeat a couple of times.....still nothing. I end up removing key, then re inserting and most times it will start straight away. It happens both when the engine is dead cold and when it is operating at normal temp. Hasn't stranded me at this stage, but just wondering if anyone else has come across it. Battery is fully charged and when car is garaged always on a trickle charger.

You mean crank no start or no crank at all?

It could be the clutch sensor switch above the petal. So the ECU doesn't know if it is depressed and the starter won't crank.

If this were the cause, I'd expect a "depress clutch to start engine" message in the instrument cluster. That's what happened on my 987.1 anyway....

No cranking at all ...lights on dash. just nothing when I turn the key.

I just found this on line, and seems like a reasonably easy job to replace. Especially If you are of a smaller frame, for getting up under the dash. (which I am not )Apart from the "Depress clutch to start" warning sign not coming up, I will give it a try and see what happens. Once done I will put the result up. Although the car doesn't get driven much and it really is just intermittent. Thank you for the replies. To be truthful I didn't realise there was such a switch so thanks Rschwerer.

I know there is an easy way to temporarily bypass this switch to test if it is the problem. Unfortunately I've not done it myself so I can't be sure of the procedure, but I think you just disconnect the wires and jump them together. This simulates the switch always on. It doesn't affect normal driving. There's another possibility that your problem is actually that your ignition swich is beginning to fail. It is fairly inexpensive and not difficult to replace. So if jumping the clutch switch doesn't fix it, then it's probably the ignition switch. I don't mean the key lock, it is a separate switch behind the lock..

I recently replaced my ignition switch due to intermittent (but never stranding) no response from turning the key. That fixed my seemingly similar issue. Indeed an easy swap. I have my old switch to see if there is a way to maintain it (clean the wiping electrical contact), but just haven’t gotten around to it yet.

I would also vote for "probably the ignition switch wearing out."

When this happened to me the first time, I was just thinking to myself, "WTH is going on here?!?!!" Come to find out, I grabbed my wife's keys, and was trying to start my 911 with her Cayman key. It didn't work But what I did find out that was interesting, the ignition switches aren't keyed. First time I had ever seen that in a car before.

Sounds like the starter is going bad. I have a 2007 Cayman and had to replace the starter in 2021 with 71K miles. Battery was fine, started intermittently, then would not start at all. It is not the clutch switch, because you would get a message on the dash. You will need some long 3/8" extensions to reach the starter mounting bolts from the rear bulkhead.

P.S. New Bosch aftermarket starter works just fine and less expensive.

I had the same problem with my ‘06 987.1 . Replaced ignition switch first- that didn’t fix it. Mechanical determined that the starter solenoid went bad, but solenoid is integral to starter., replaced starter- problem corrected. Now if i could just get the remote to consistently lock and unlock the vehicle I’d be happy as a clam.

I had the same issue on my 2009 987.2 @71K miles and replacing the ignition switch was the solution. Then a couple of years later @86K miles, I had intermittent starting issues and it turned out that my starter was bad. That was a pain to replace as it sits on top of the engine under the plenum. It's not tough to do, just a lot of things to remove and move out of the way.

Thanks all, lots of ideas to work on there. Starting to sound a bit like the ignition switch or starter motor could be the culprit. Especially as there was no notification on the dash for the "depress clutch to start" warning. Again thank you all, you have been very helpful.

I had the same issue happen yesterday. I have a PDK , so I am leaning toward what the others have noted above. YT video I found with a quick search.

exactly what happened to me years ago, intermittent starting, it was the clutch switch, quick easy fix.

The video linked above is an excellent resource, and I followed the first path that was more “contort your body and feel around more” which took maybe 10 minutes? At the end of the video he gave 2 options: 1) no key chain, and 2) replace your switch every 18 years. Well, this thread prompted me to pull my switch apart and see if there was a 3rd option of just cleaning things up. This is the ignition switch out of the car starting to be disassembled. This whole thing is multiple layers of parts being snapped together. The outer box has 10 small snaps around the perimeter holding the front cover to the back cover. I used 2 tools - a small screw driver to gently pry open, and then a spudger/trim tool to hold open as I worked other snaps loose. There are then 4 larger snaps holding the rear cover to the internals Once you get those snaps undone, you see the guts of the ignition switch and the back side of the internals showing the circuit board, which is attached via a small white electrical connector and 4 plastic clips on the sides removing the PCB shows the wiper contact interface With a detailed view of each: I marked the PCB just to get ohm readings and map the pins, but ultimately I don’t think that was a very useful exercise. Anyway, nothing obvious jumped out, and my best guess was some grit and oxidation. So I wiped off the contacts, gently polished with some 2000grit wet/dry sand paper (I’m sure there are better tools for this job), and reapplied some white lithium grease before snapping it all back together. I’m fairly confident this would, at minimum, make the switch more consistent if not completely consistent. It is a low priority for me, but I’ll likely be swapping it back into my car in a couple weeks just to verify the “fix”, but ultimately I’ll just keep the new one and if this one seems good sell it on to someone who doesn’t want to go through the above effort (which really isn’t much effort at all!). I hope that helps someone

The post above has been copied into a new DIY thread on cleaning the ignition switch. The post is very familiar to me - since I wrote something similar three decades ago for the BMW K-bike ignition switches, which started getting flaky at around 50,000 miles. Very nice step by step and wonderfully illustrated - congrats on the Technical Contribution Award! (and permanent paid membership..)

STANDARD MOTOR PRODUCTS​ US1034 (US-1034) Ignition Starter Switch $ 147.79​ $ 0.00​ 1​ $ 147.79​

Rock Auto

Thanks mate

I am expriencibg the same thing. It started by being intermittent at first and this week it doesn’t start at all. Just a click when I install the key to start the car. My Porsche mechanic told me that it could possibly be the power cable which apparently is common with our models or the engine starter. The battery has full charge. My car will enter the shop this week for diagnosis.

please let us know the result.

Also curious about the official diagnosis, but I’d put my money on the ignition switch.

as some earlier postings mentioned - it can also be the starter. its a known weak point after about 10 years.

Will follow up

Eye of the Tiger - Thanks for all the useful posts! Have a good day. I am back in KL... still with my 2011 987.2

07CS Intermittent start. Eliminated clutch interlock switch; bypassed permanently. Sometimes it would start on first attempt, sometimes 2nd or third attempt. All dash lights an sounds were normal. Battery positive lead checked good; zero looseness or corrosion. Removed and replaced starter.... all good now for last couple years.

And for those among us, including myself, that have bypassed clutch interlock switch, always inform anyone working on your car. I also tape a note on my steering wheel that says: "Clutch switch bypassed Do not remove this note"! This way anyone who gets behind the wheel knows. I also take a picture of note taped to steering wheel when I drop off. Ashame I don't trust anyone.

@WTFChuck - Yes, permanently bypassed with exactly the same remedy, just 2" of wire. And yes, I was going to replace. Have a new one in the box. Read on, not for the faint of heart: When my clutch switch failed, at the time, didn't even know about it I was ON the tracks of a very, very rough railroad crossing. So bad you almost need three feet to get across with a low slung manual, without scrapeing. 1 mph is to fast! Semi-rural area with horrific RR X's, I could not push it off! I WAS FREAKING OUT! No one around. I was sure a train would come before I could get help. F*** ME! I tried starting it 3 or 4 times before I tried to push it off. You know how that went. I looked arond, maybe something I could use to pry it off the tracks, no luck. About 3mins in, Freak Out now at 11. It took about 2 more minutes of frantically trying to start before it came to life. Approximately 5mins total, felt like 2 lifetimes, I kid you not! All the while, a video playing in my mind watching my Pcar get demolished. So no, I will not be installing clutch interlock switch. Just stick with what works for me. May catch up with me one day? However, if a shop damages my car because of this, it's on them. They will pay! As heartbreaking as that would be, I hopefully won't witness the event.

FYI, this happened shortly after my CPO expired. Tells you I always engage clutch when starting. That's how I was taught. Had no clue about said switch until failure. Go figure! Maybe now I'll change the switch. Put my jumper in glove box to insure switch longevity! Thanks @deilenberger , as you have a great point.

Now, that is one undeniable reason to not feel the need, nor want, to replace that clutch switch. Had me sweating reading it. A friend has a long standing fear of elevators. But that is due to being trapped on one for several hours, and as she says, “if you haven’t been there you have no idea what it feels like“. Keep what works for you.

@WTFChuck - True that! You don't know what you don't know, until you know! The experience was horrifyingly surreal!