My Porsche 911 996 Carrera is broken AGAIN… can you help?!
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- Опубліковано 11 тра 2024
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HELP, dear friends of 9WERKS TV! My 1998 Porsche 911 is still cutting out and struggling to start and I just CANNOT get to the bottom of what is causing it!
The 996 is going back to my friends at Wrightune shortly for diagnosis but so far we're all at a loss as to what the issue could be. If you've any ideas, let me know in the comments below!
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Hey friends! Just a quick note to say I’m pretty blown away by all the helpful comments offering advice. THIS IS SO MEGA! Thank you for taking the time to give a sh*t and reply. Feeling pretty stoked that such nice people watch this channel. A sincere thank you. ☘️
We all feel for you. I think most of us carlovers have experienced similar periods of true despair ( I know I have😏).
Regarding the idle control valve...the same part is fitted to bmw z3s which can be purchased really cheaply....i replaced mine for about £20
Just watched this update Lee, sorry to see you're also having 996 maladies. My gut feeling with this is that it's related to fuel pressure, especially as it's exasperated by heat. My first checks would be checking the fuel pressure from the pump both hot and cold. I'd like to see the pressure directly after the pump and then the pressure being held at the fuel rail. My money is on either a failing fuel pump or a failing fuel pressure regulator.
I hope you manage to get to the bottom of the problem soon!
Hi Lee, Make sure you check the alarm module. It can be known in our old 996's to do all sorts of funny things. Had problem with my 996. Would not start intermittently. Different shops checked different things and couldn't find anything. Then started to cut out whilst driving...Anyway changed alarm module after lots of reading myself as that has sorted the problem. This was changed at Manthey after they too couldn't figure it out. I insisted on just trying a change of module and that did the trick. The problem is its under the seat and over time it can get moisuture and things affect the electronics. I can't say for sure if that's your problem of course, however just have this in the back of your mind just in case it is
jonny on the late brake show (youtube channel) just did this to a 986 and fixed a bunch of startup and window and trunk/boot opening issues. after that i would try ignition coils and plugs, test the fuel pump, and clean the injectors. fuel pressure regulator and fuel filter also. many cars will do a safety shut down if they detect low fuel pressure.
Yes alarm module problems can cause all sorts of issues and particularly when you can't find something else or very intermittent then it's likely to be the culprit. Mine kept having a failure indicator light coming up. Anyway worked for me
The potting agent that the solid state electronics are held in degrades over time and then you start to get issues.
Leave it with the mechanic for two weeks and let them use it every day.
Sorry to see this Lee. These things are sent to test us…and it sounds like youve been thoroughly tested! Hope you find a resolution soon and fall back in love with Little Irish once again
This is screaming fuel pump. Your mechanic is can scope it with an oscilloscope, it will have a perfect sawtooth wave form if it's good. You should also have fuel pressure tested after shutting off to rule out the fuel pressure regulator.
My thought too. Haven’t had this happen in my 996, but exactly this happened in a previous car I owned. Good luck sorting it!
That was my first thought, but a fuel pump would be relatively unaffected by temperature I would think. The gas stays pretty cold in the tank.
My guess is fuel pressure regulator. Time to go back to basics on troubleshooting. Fuel, air, spark. If spark is fine, air supply is correct, then problem is fuel related. On my 968, FPR went bad and knew because of hard starting and when I took it off, found fuel in vacuum side. Replaced and no problems since.
While diagnosing the fuel pump. Check for cracks in the fuel pump pickup tube.
Have you vacuum tested while white. Possibly crack in the intake or hard intake gaskets
Time to replace the fuel pump, fuel filter, and injector service. Might be good to update the DME Relay too.
I had a similar fault with my 996 and it was the fuel charcoal canister
I would check resistance and voltage on the throttle body, also check coils, you could have coil braking down, always start from basics and not throw $$ and parts at it, could be anything simple. This is what O would do.
Check fuel filter, fuel pressure, fuel pump
Check live data on injectors, could hve one dirty, or one intermittent not working properly, Trow a redline bottle in it
Check coils for resistance, they tend to break down with heat and give you intermittent shut offs, had this happen to a bmw 740il that I used to own back in the 2005, changed all coils ,done deal.
Check throttle body for resistance and voltage
You have replaced all the rest. Just my 2 cents👍🏽
Agreed on coils and heat.
Bad coils would cause misfire and erratic idle, especially when warm.
I had very similar issued on a 986 once. Whilst the idle control unit was working, it was operating just out of tolerance, which was ok when cold put wasn’t performing correctly a temperature. Might be worth checking the output signals when the car is warm.
The warm starting problem is usually-always the Y-cable. The Y-cable is very well known problem both in 996 and 997. But never encounered it shutting down in traffic lights. What it did with me was that occasionally when warm it did not want to start, like low voltage, empty battery. But you try a few times then it is like ok again. Since I renewed it - no problems. Perhaps your's sound more like fuel/air/idle problem. MAF? Don't buy "Porsche" (by Bosch). Buy the exactly same "Bosch". It is like 40% cheaper but exactly the same. You can also buy MAF cleaning kit. Never touch the hot wire/foil with fingers.
What does your voltage give while driving? Should be about 14 V when charge cycle on. Off cycle can be less, but should be above 12 anyway.
I have the 1998.1 C2 but I dont remember if you can read fuel pressure from that generation OBD? My 1997 Audi S8 did that shutting down in traffic lights and it was the shift pump in the fuel tank that was working only when it wanted - until it decided to retire completely - and my OOOO left me standing at a Porsche Center :))) when I was getting spares for my baby. Old cars!
One more thing came to my mind. The AOS little tubes into the plenum overflows sometimes. Last time I had my engine out the plenum had a little lake of oil in it which then lead to changing the AOS. But I think the basic problem was that I kept the oil at max level (due to the stupid IMSB stories). Now I keep it at at least 1/2 by the gauge which still keeps the IMS well submerged.
My car is at 130 000 km = 81 000 miles. If I remember correct yours has quite a bit more so it could be any electric sensor, wire, earthing. Induction air would be my first guess in this case - but I think MAF is the source.
Battery and or charging system issue. Note in your video @2:16 the voltage dropping when it dies.
My 997 had a similar problem some years ago. When the engine was hot (I.e. it ran for several hours), it was very hard to start again. The positive cable of the battery was renewed and since the the problem was solved.
was thinking this when I watched the video, but, when I had a Cayman 987 s - it mostly related to hot start issues rather than the car dying on me?
@@Ussyb10 that is true; the car did not die on me. I tried to help with solving Lee’ s problem by sharing my experience, as everyone in the comments has 😃
My 986 suffered from not starting again if I stopped for a short time with the engine hot. Had lots of work done including the fuel pump. In the end it was bad fuel. I would get the fuel tank completely emptied and then put in fresh high octane fuel.
Yeah as 997 owners i agree with this
Have you looked into the EVAP purge valve. I had this exact issue and only when the car was warm.
I'd say it's the idle control valve that needs cleaning! You can clearly see in the clip that the old one is not closing properly. I had the same issue on my 964, ICV seemed to be working but after cleaning it the problem went away.
Could it be the fuel Evap system malfunctioning?
I agree with those above that said to check your fuel pump and fuel pressures. In the air, cool cars this kind of behavior has happened to me several times. I first checked the auto control valve like you did. It turned out to be a bad. dME relay. I don’t know the exact particulars, but that relay has a significant impact on ECU performance, fuel pump performance, ignition performance. There’s a company named focus nine technology that makes solid-state relays with test lights on them for many 911s. Off the top of my head I do not know if they make one for the 996 luckily I have not had this challenge with my 996 turbo yet. Having two air cooled cars, I learned a long time ago that I always carry a spare. DME relay. A friend of mine has bought two 944 turbos that were supposedly not running, only to bring them home and change the DME relay and realize they ran fine. If you want to test this, it might be worth trying to find someone that has a working relay in a car that’s good, I just swapped the relay to see if it makes a difference.
The DME relay controls the fuel pump entirely. If it completely fails you will have crank but no start.
You will find the problem. Don't give up. I know it's frustrating but the car is worth it. Happy Motoring!
Sorry for your troubles hope you get it sorted.
Grim! Feel for you...
Sounds fuel related to me pump could be getting hot and sticking. I think it’s back to basics when it happens check there’s a spark or fuel getting to the engine
I actually had the exact same problems on my 98 996, watching the symptoms in the video almost gave me some sort of awful flashback!
In my case, i replaced the MAF (the MAF was actually giving zero readings) and the battery around the same time. It has been running for about a year now with no hickups.
If the problem was to persist, i would probably try swapping out the Y-cable, like many here have mentioned.
Batteries can be a bit tricky to test without a proper load testing setup, so it might initially seem just fine, but still have dead/dying cells.
I have also heard stories of people recieving brand new MAF sensors that have been DOA, so it might be worth another try.
I wish you the best of luck with your electrical gremlins!
check 180 amp wiring on alternator for melting
I wonder if hooking up fuel pressure gauge before replacing pump
also ignition switch would be a good place to start
I wish I lived closer to you
unfortunately I moved to Florida 20 years ago
system voltage is huge also make engine ground is good very important
ive even seen the one way valve on the fuel pump cause similar issues.
good luck
Replacing the cabel from the battery to the engine helped in my case when my 996 (99) had similar issues a few years back.
Not sure if your 996 has one and, but could possibly be the DME relay if it has one.
Sounds like you need to start live data logging to check spark / fuelling etc. Obviously now is the time to do it when it's most problematic. My first thoughts were piston rings or scoring, but if its so intermittent it must be electrical. Relay related to fuel maybe?
Did you not have the oil filler replaced in the last 18m? Your video helped me with the same problem and that caused me to lose revs. Because it seems to be heat related is there an issue that exposes a leak when hot? Perhaps worth having a look.
Lee, sounds like a fuel issue to me. Check the FP relay first, make sure there's no dry joints. If the relay is OK, replace the fuel filter (if not already done so). If that doesn't solve your problem then replace the pump.
The Y cable(and associated power cables) would be my 1st check. Did you notice the volts dropping on the dash.when it was playing up? Quick check is monitor volts when tuning lights(a load) on and off. If it's dropping below 13.5 v, engine bay power cables need checking.
We would be happy to look at the fuel system for you and provide some options if it is the fuel system. Protec Fuel Systems have been a supplier to Porsche Motorsport for over 14 years.
VACUUM LEAK!!!! Always blame the easy stuff first... if you car does not start, dont get a new engine, check the battery lol. Apply this to ur car and youll save a lot of money and headaches. Honestly, electronics just dont fail like people think they do. They work almost always without fail.... Just a thought. Sorry if u mentioned it in the vid as I am wiriting this while watching
Hi, I am sorry to hear the issue and I hope you find a fix soon. Whilst I don’t own a 996, I have a 997 Gen 1 which uses a similar design engine. I believe I had a similar problem before and the issue went away after I replaced the Oil pressure sensor. I am not a mechanic but I hope this will help your 996 to get back in shape. Thanks
I’m no mechanic but I had the same problem with my ‘03 996 … it was the battery cable going over the rear wheel arch to the motor. It would intermittently cut out only when the car got hot. The heat (here in Australia) would overwhelm the cable and the power to the motor would drop out ….the cable is fairly inexpensive and often gets over looked. Good luck
Hi Lee, This sounds like classic DME relay symptoms to me. Order one of those and change it over. If that doesn't cure the issue keep it as a spare in the glovebox coz sooner or later it will be the issue that gets you stuck mate. they're only around £40 or so
Check the fuel regenerative valve, similar symptoms and replaced a ton before finding that solution.
My Early build dies this as well but 90 % of the time just catches itself before actually dying. So it bobbles between 500 and 1000 then settles down after about 4 bobbles. I’m guessing it’s the tune. It just needs more fuel. Take it to a tuner and have them read fuel tables if possible.
Intermittent issues suck. Sorry to hear. I hope you’re able to get it resolved. These old cars need our patience when things go downhill.
Like many others, had fuel pump issues on other cars - mine was an Audi 200 quattro Avant - which exhibited almost exactly the symptoms you’re suffering. The pump is within the tank and fuels variable quality eventually kills these pumps. My guess is the pump is at the end of its life. Not the most pleasant job to remove and replace but ultimately an easy fix. Best of luck Lee!
Sounds like an electrical ignition system issue or fuel pump to me Lee, could be the fuel pump relay - reminds me of the dreaded DME from my 944 days! Best of luck with it 👍🏻
Oh, how I know your pain ! A whole year we were chasing symptoms VERY similar to what you describe: from cold, running well for 30 minutes or more (if cold outside), then dying. Leave it for a few minutes and it would start again. 10 minutes later, dead again. I spare you the whole history of chasing electrical and fuel possible faults, as at the end it was the lambda sensor in the catalyst section that was causing „limp mode“ and then „recover please mode“. New sensor removed issues for now more than 10,000 km with NO stop, at all (and better mpg). Caveat: this was on my 964. May help, though.
Lee, I have a 1999 996 and have had the exact same issues with my car and have changed all the parts you have, still have the same problem. I think I have got to the bottom of my issue which might be the same as yours. It could be either the fuel pump or fuel sender. My car cuts out at lights when hot and has erratic idle etc, it gets increasing worse when the car has low petrol, but never happens when the fuel tank is above 3/4 full, which is obviously helping the pressure of the fuel. It’s going in to have this done on the 28th May so will let you know if this cures he problem, like you I am losing confidence in the car and I don’t like driving it anymore.
I wish ....for just test driving a few days.. you could installed fuel pressure gauge mounted by front windshield (outside side). I did it to my 1980 camaro...It helped me watching nonstop fuel pressure for few days of driving hard and normal. That was my problem. I also have 2003 Porsche 911 ..175000 miles ...no problem with inside the engine yet.. Buying best gas and changing (by myself) Mobil 1 oil like crazy every 3000 miles just to be safe,
Hey there! Assume it’s fixed now as saw you today on the M40 Stratford direction!! Couldn’t believe it (that was me in the white Tesla Y btw) …also a fellow 996 owner though;)
Great to see you
Cheers 👋
Long shot but have you checked the earthing strap Lee or possibly fuel pump?
I have 2004 boxster S. I’m in the U.S. I have similar issue which becomes very apparent when I travel to coastal city(high humidity) in hot weather. When coming to a stop at a stop light when I push the clutch in the engine will stop unless I hold the revs up to 1000 or greater. It is less of a problem in my home city which can be just a hot but with much lower humidity. The problem started when the car was about 15 yrs. Old. I typically used 89 octane (mid-grade) but decided to use some 92 octane just see if it had ann effect. The stalling-shut down problem stopped. Strange but obviously fuel related but I don’t know in what way. I just purchased a new one from amazon for $21, appears to identical to OEM. I’ll see when it arrives.
Oh no.... I know how this feels when a project just doesnt feel right anymore. Get this sorted please... and let us know what was the issue. It seems to be not that uncommon...
I like your little irisch content!
I did see this happen to me in a 991.1 C2S where the engine cut out randomly, but starting it up again it was fine. However this only lasted for one tank of fuel lol, so im putting it down to th E5 Shell Vpower I put in was not great at the petrol station. Filled it again from the same place a couple weeks later and it was fine. Never put E10 in though.
How does the fuel pump sound when it primes cold vs warm? If you fill up with new cold gas on a warm engine does the problem get a little better. Do you have a mechanics stethoscope? If you do, throw it on the fuel pressure regulator and listen, do you hear a difference warm to cold, does it sound like something surging? If yes to all this maybe think about getting a pressure tester on the fuel rail and see if you need a new pump or regulator. Otherwise you’re testing continuity on hot vs cold wire harnesses for all the usual sensor suspects
Just a quick thought, if you feel it is temperature related, then try retesting the ISV etc in a hotter environment? Nick Mrs Sibs hair drier perhaps and blast it whilst Andy does the multimeter? The kitchen table will be much cooler than an engine bay, so might not show up the fault. Good luck mate.
Fuel vent system I guess. Hot temp = lots of vapor. No ventilation, is no fuel to feed the fuel system. Hope this helps
I was about to comment this! Be interesting to see if when the problem occurs if you open the fuel cap does it go aeay
Thank you, I'm having some similar issues if not exactly the same, and I know there's a problem with my bleeder. So crossing a couple of fingers more now that replacing it will sort things. 🙂
Stuff like this is annoying!! Get a cheap scanner and check for any pending codes as soon as the engine shuts off, not the stored codes as they’ll set the check engine light on (if that’s on?)... Also test the relays, primarily fuel pump. Leave the carpet cover off or loose and see if any get hot after driving around.
Looks like you got all the advice already 👌🏻
If the crank position sensor looked like it did coming off it might be worth while looking at its plug and cable too.
Could it be a bad fuel pump? Or the wiring harness/connector to the idle control valve?
Not on a Porsche but a bad battery gave me similar symptoms once. Almost like the coils were dropping out, but no fault codes.
Fuel ? what do you run it on, if supermarket cheep stuff I would try Shell ultimate, makes all the difference, I now even put in my diesel daily and have noticed a change. Ps I dont work for Shell by the way ! What about coil packs, are they by there sell by date, other than that the ignition barrel / wiring, somthing moving especialy if its doing in as you pull up.
Cook packs new this year, I tend to fill up at Shell - loyalty card takes a bashing!
I would search electrical indeed. Improper grounding a cause all kind of weird things. Fuel pump for instance needs proper ground to operate correctly. Go around with an Ohm meter and look for slight higher resistances. Between metal parts.
I know on aircooled cars when the fuel pump starts to go it behaves exactly like you are describing is happening to you. Maybe want to replace that. Those things can act intermittently for a longtime before they finally quit. Best of luck.
Could potentially be the fuel sending unit and pump. I had a similar problem and replacing those cured it.
Been there done that; DME relay 100%
The positive cable junction block at the starter on top of the engine, toward the front, is notorious for internal corrosion. It can cause many many issues, especially when hot. I replaced mine based on the symptoms of dying when hot and slow to start when hot… along with draining battery. Low voltage can cause a lot of strange behavior.
If you’ve never replaced the positive cable, you should do so regardless of your current issues. Best case scenario it solves them all. Most likely it will help you narrow things down.
Hey Lee! could it be the fuel pump? a few have mentioned fuel, I know these can fail and fairly easy to sort
Is it a fuel vapour lock of some sort, or ignition system?
Feel for you Lee, hope someone helps you get to the bottom of this, little Irish will be back to full health soon enough.
Maybe the feulpump? I had that with my Gti when it started getting hot in the summer. Took us years to get to the problem.
Sounds like it could be a fuel related problem, maybe fuel pump or connections. Good luck sorting it out, don't give up. All the best.
What is your throttle body like? Similar to yours my gen 2 was stalling in traffic or at junctions, erratic idle, hard to start when warm, etc, but not throwing any codes. I tried a few things and I dont know why but ended up removing my throttle body and cleaned the grime from behind the butterfly. There must have been enough there to choke it up at idle and make it either hunt or die. Cleaned it up and it was like new brand again and the problem never came back. Worth doing as a quick and free DIY job so you know it is right
I had similar issues with my 986. Turned out te be a defective brakebooster. This creates a vacuum leak. I had no engine light but same issues. Apparently this is a known issue and a retrofit is available to prevent the brake booster leaking.
Do you have a lightweight flywheel? If so, this might be the cause. The ECU might not be able to work as fast when revs are going down more quickly. That's at least something ive heard about. This might be a thing to check..
Yes have a SMF, it’s been fitted for about 80k miles, never any issues previously and I covered 70k of those.
@@9WERKSTV Hmm well that most likely doest come from it then... But the symptoms you have made me think it could be the reason... Fingers crossed, that you find the cause of the problem asap to enjoy the nice weather - at least its nice here in Germany at the moment ;)
Timing chain stretched. Or camshaft sensor or worn timing chain guides. So for my guess timing information sent to does not meet the expected timing readings.
I had similar symptoms and replaced crank sensor, turned out to be a the fuel pump was dying
Our 914 would die in hot weather when the engine was good and warm. It was a vapor lock. The solution was to move some part of the fuel system to a cooler location. When the car died it would not start until the engine had cooled down, so the symptom is not precisely like yours. Good luck.
Evap system purge valve have you tried disconnecting it sorted my 986. I was chasing the issue for over 12months.
I heard of someone else having this issue and iirc it was the high pressure fuel pump that needed replacing.
Did you change the power cable to the starter motor when you put a new starter in? these can be known to corrode, I am clutching at straws here but could be causing electrical problem. John Vdub at the pub
I’d go back and check the MAF. Just cos it’s new might be dodgy. Assume no smoke? So not a/o sep. what does the 996 have in terms of EGR? Cat sensors or exhaust sensor related given its worse in the heat.
Lee, I really feel for you. I think it might have something to do with the fuel pump. I can see you are frustrated, especially when you have spent so much time and money without a result. I hope you find the solution asap!
Hi Lee, have you changed the DME relay?
In tank fuel pump. I've replaced loads, I change them along with the crank sensor as a matter of course on 986 and 996s.
Would be good to know fuel pressures when it dies.. dud pump? Pump relay? Does the ecu enable you to log that information
Same with my 996 but not as bad as your one Lee
Possibly the engine bay purge fan not functioning, causing fuel evaporation when hot?
I hope the eventual answer is straightforward and inexpensive Lee.
Watching your video with the heat in mind and the fact its cranking and cutting out and what i would say as not lot ignition off ie instantly.... Its air or fuel starvation... My gut is telling me FUEL STARVATION... Cant really be sure why but just the way it died ? And struggling to start ... Ecu does have control over fuel injectors and maybe fuel pump ? .... Air i think easier to disnose and not cut out as quickly... So either fuel pump , lift pump or injectors or what controls them electronically... Just my gut from your videos... I think i would take the ecu plunge repair as cheapest rule in or out 🤞🤞🤞 🙏🙏🙏 fingers crossed buddy i feel your pain
Sorry to hear that Lee. Porsche ownership can be a PITA
Does it ever happen if your tank is three quarters full or more with fuel? Just sounds familiar mine dropped revs when about a quarter full and I think as someone else commented it might be fuel pump or fuel sender related
Hello Lee, I was wondering if you have any faultcodes from the ECU, from you recent post I think you had no fault codes right? Temperature sensitive problems often lead back electronics. It is just a thought, but if the ECU fails, causing the car to stall, it can also not write faultcodes to the ECU. Is it possible to keep a record of the OBD output for some time? Keep a dongle plugged in while using the car?
I heard that there is a Y cable to the alternator that can cause similar symptoms. Not sure if this affects the 996.1
Surprised it wasn't the crank position sensor - had the exact same symptoms on my '98 996, that solved it completely.
EDIT: Someone else mentioned the alarm module... I actually had my immobilizer rebuilt around the same time (water damaged from a clogged drain left by a previous owner). May be worth investigating. Lives under the driver's seat on LHD cars.
Fuel pump / fuel pressure would be my guess but swapping the alarm module as posted elsewhere would be an easy test.
I had the same problem with 30 degrees plus. But it seems 95 E10 petrol related even with one time purchase. Full throttle it will start again. Always take 98 E5 Lee.
Yeah e10 causes my car to misfire
Hello everyone! Since we are on the topic of 996 problems, has anyone ever run into bank 2 on the passenger side running rich and causing the exhaust tip on the driver side to blacking up all the time? I feel no lack in power or drivability but haven’t be able to get to the bottom of it. Hoping somewhere here has maybe seen the same thing. Absolutely love this channel and all the amazing people here who help figure all the little bits out! Cheers from the USA! Thank you Lee!
Hi, you should check your O2 sensor in the exhaust for that bank. The 996.1 has one per side and the 996.2 has 2 per side. If you have a bad O2 sensor the ECU compensates by running Rich to prevent engine damage.
Is it running rich or is that your assumption from the exhaust tip blacking up? Reason I ask is more commonly this is bore scoring.
1. I see you testing equipment, but I don’t see you testing equipment that is hot. What would have a significant delta between hot and cold function?
2. Electrical is pretty binary when it fails: *except*… when something else is expanding due to heat, it could be creating an unintended junction with something electrical, creating a temporary short/junction.
Good luck, Lee!
Have you checked battery wires that all cables are fit snug?
Replace the crank sensor again, part could be faulty… it still points to this issue… if not fuel pump/evaporator good luck 🤞
Time to rename it. That will solve it.
I use a mechanic , to work on my 996, who has been working on Porsches since the 80’s. Dealers, including Porsche, send puzzling cars, like yours, to him to work out and fix. Been using him for 15 years plus. If you would like the details then let me know
Go back to the fuel process. Air lock? I don’t think pump from what you say. Fuel filter? Someone mentioned the evap? No idea but I’m thinking cats, cat sensors etc. and always make sure battery is full full.
Se if its possible to log the fuel pressure when the issue happens.