987.1 Intermittent starting issue

To start, my car is an 07, 2.7 Cayman with 55,000 miles on it. Major service was preformed by Porsche at 50,000 including new spark plugs , fluids and a new " Porsche " battery installed. I made certain of this. Here is the issue. The car could sit for days or an hour after driving and crank right up. The problem is after turning the car off and then trying to restart within 10-15 minute intervals it barely turns over. For instance, if you were to get gas and then stop at a store briefly, then try to restart, it really struggles to turn over almost like the battery is going dead or loosing a charge. But there are no other tell take signs of the battery being bad. If it wasn't going to hold a charge it would be dead after sitting for two days but it cranks right up in this situations. Another instance was today, first drive of the day, car starts right up, I drive it to a touch less car wash about 10 minutes away, turned it off while it was being cleaned then tried to start it and it was completely dead. I jumped it drove away made several stops after that with no issues ??? No TPMS acting up, no lights on the dash, nothing. Anyone else experience this anomaly ? It can't be the battery or alternator because if it was either of those it either wouldn't stay charged or receive voltage to be charged. My guess is the starter but that is just a guess and why is it only happening when turned on and off in short intervals? I'm baffled, I have about 6 months of an after market warranty left that I am going to file a claim under because I am not taking a chance of getting stranded. Any ideas? or anyone else ever have this sort of thing happen? PS this has been happening for months now, today was the first time it actually wouldn't start at all. Regards and thanks in advance, Brian Any advice is appreaciated. Sent from my iPhone using Tapatalk

You might have a bad cell and not generating enough cranking amps since you drove with components that might be drawing current. When's the last time you replaced your battery? Most batteries last 4-5 years on average but also depends on the region you live in. I would start there since it'll need to be replaced soon if you haven't already. Let me also add. Check your battery connections just to be sure that it isn't loose. Some technicians will pull the ground cable to avoid any shorts while in service.

Easy enough to get the battery tested and that should be your first step. I suspect a battery issue. Good luck.

I stated in the beginning of the post that the Battery was replaced with a new one from Porsche (OEM) at 50,000 miles. 6 months ago. When you say "bad cell" could you be more specific please? Sent from my iPhone using Tapatalk

How would you suggest testing the battery . Dealer wants $150 to do a Battery test. ? Sent from my iPhone using Tapatalk

The Battery is virtually brand new Porsche OEM. 6 months old, I know parts can go bad but this has been happening for months and progressively getting worse. ? Sent from my iPhone using Tapatalk

I'll be following this thread, I have the same symptoms and my battery is less than a year old. I'm thinking wires, but then again I live on the Wet Coast

How old is your battery and have you had it tested?

Less than a year, and no I haven't had it tested. It only happens when I've been driving the car for a while, then take a brief break (e.g. fill 'er up). The battery seems to be dying after a hard drive... it's weird.

Yep, same exact symptoms with my car. First thing is to rule out the battery . (my gut tells me that is not the issue) then I'm going to firmly request the dealer resolve whatever this phantom problem is. I am thinking wiring or perhaps the starter or a solenoid. Out of curiosity what year is your car ? Its reassuring to know that there is another Cayman owner having the same issue for the simple fact that if it comes down to it this should help us when dealing with Porsche as it is now confirmed as not being an individual occurrence. I will keep the thread updated. I hope to have this resolved prior to the new year.

This is not an unknown issue and has nothing to do with your battery . Change your temp sensor, the temp sensor misreads and thinks the engine is cold and fuels for a cold start even though the engine is hot. This effectively causes a "flood" of fuel and it won't start. After a few cranks it'll pick up and fire. I had this issue and I've already posted about it if you check my previous posts you'll see it. I changed my sensor and cleaned the fuel system with a Forte treatment and I've NEVER had it happen again.

Thank you Chris, I will check your prior posts, perhaps you have detailed all of this there. A couple quick question, is the job easily done? or require the car to go into the shop? I can preform simple routine maintenance but that's about it and where would one purchase a temp. Sensor for our cars?

The temp sensor is at the cabin end of the engine and can be accessed from beneath the car. I had the shop do mine as you lose a fair bit of coolant. The sensor is only about £15 as I remember and it took my local Indy about 45 minutes to switch it out. I think you have to be very quick or you'll dump all your coolant and there's 19 litres of it!! Clearly the system will need bleeding to prevent air locks and hot spots in later use.

I got my sensor from my OPC parts dept.

I will clearly need the dealer to preform this. I searched your prior posts but could not find anything in regards to this topic? What is the title of the thread? I would like to have some ammo to take to the dealer when I present this solution as they thought it was a Bad Battery as well prior to inspection, that's when they quoted me $150 US for a Battery test?. I have an after market warranty that I will file a claim against. Are there other tell tale signs that the temp. Sensor has gone bad or should they be able to tell by some form of testing? Is this a known issue documented with Porsche or just among this community? Thanks again!

OPC? Dealer?

Yeah your dealer (OPC - Official Porsche Centre in England)

I was told about on a UK forum. Mine used to do it every time I stopped for petrol but only ever after the engine was hot, it was driving me crazy and it was a little embarrassing to boot, Porsche not starting in a busy petrol station is not a good look!! I researched it in the UK forums, found the solution and had it confirmed by a couple of others and went for it. As I said, I've never had a repeat if the situation.

Search for topic "starting problem" started by SJO. You'll see that he had the same issue and resolved it the same way.

Thanks Chris, your awesome! Very helpful as this too was driving me crazy, as you have experienced first hand. I will try to find the additional posts. What did the total cost of repair amount too. I am guessing by the time for repair/labor and cost of parts around $200 US ? Happy Holidays, Brian

View attachment 27520 There you go, photo of the invoice. Have a great Christmas and a smashing New Year.

I'm not sure you have a temperature sensor problem, based on what I know. The sensor problem is heat related also but the car will crank over normally without starting because of the sensor mis directing the amount of fuel etc. to feed the engine. Your problem, as I understood it was that the car cranks very slowly as though the battery is all but dead. Two distinctly different problems I believe.......but I've been wrong before.:cheers:

When I suffered the sensor issue slower cranking was a symptom, initially I thought it was a crank position sensor issue but it turned out not to be the case.

very good information. Cayminister, good luck and post back with your findings.

Thanks Cheech, At this point I am sticking with temp. sensor. I will research further over the next couple days but this seems to fit the symptoms precisely. I am an engineer by trade so I am determined to resolve issues that prevent things from operating as they should. In Hindsight I should have been an automotive Engineer... I also live in the Birthplace of Henry Ford and drive a a German car. Go figure. ?

Yep, sounds familiar, just had mine done last month, I also had another sensor malfunctioning that was triggered off by this £20 sensor. If you go to a garage that has the correct diagnostic equipment (I went to a Porsche Indy garage), when they hook up to your cars computer, they will find abnormally low temp readings from your sensor, mine dropped out at -39 Centigrade, (no wonder she was giving me hell!). In the end my Oil level/temp sensor was also playing games, but that all cleared up with a new water temp sensor. I'd get the cars computer readings checked out to confirm, and I'd also get the old faults cleared off. I should add that the cars dashboard did not indicate that there were faults, i.e CEL's, but on examination it had stored three seperate faults, and they all read exactly the same fault and temperature. Cheers Rob

Which Indy do you use Rob, I'm assuming you're UK based?

My temp gauge is fine too, but the car has exhibited the same issues you mentioned. With 50k miles on her things will wear out, I'll buy a new sensor and install it myself (this will likely take a while due to work/life commitments). Let us know if the sensor swap solves the problem.. Thanks, Jeff

Will do Jeff, thanks for the posts.

It is, thanks. Hope this solves my related problem too. Scott

So will the coolant flush and bleed benefit me in any other way than the peace of mind that the motor now has had a new coolant flush/fill?

Not to burst your buble but you may want to read the entire thread. I am guessing you have not given your conclusion. The car starts with a cold engine every time, without hesitation. The problem is a bad coolant temp. Sensor. Many have had the same issue with their Caymans, with the same symptoms and solved it with this $24 dollar part.

I now need to revive this thread- After having the temp. Sensor replaced the car now starts fine when the engine is hot. But does not between short start stop intervals and once needed a jump just the other day. In spite of starting every morning no matter what the temp no problem. Here is a typical example. After driving 5-10 miles, stoping for lets say a half an hour, car starts right back up, then if I drive down the block, stop the car for 5 minutes and try to start it again, the car barely turns over. Once after getting gas the other day, the car started right back up, I then immediately drove into a touch less car wash, started it up again (no problem) stopped at the store(5 feet away) came out the car cranked once then clickedy click ( battery dead) the horn double chirped and headlights flashed when I tried to turn the ignition over ? I jumped it, drove away and all was fine until today. In summation the problem seems to occur after the engine is hot then in between very short start stop driving intervals. Any ideas? Temp sensor is new, battery is a 6 month old new from Porsche battery .

Hello Caymanister, Just because you have a new battery don't assume that the battery is good, you should get it checked. Also, your electric symptoms could be caused by a loose ground cable.. .

My 968 did this. Exact same symptoms. My problem was, in large part, a bit of corrosion between the negative battery clamp and the wire attached to it. There was too much resistance between the wire and the battery post to allow enough current to get the starter to turn over fast enough. Replacement of the battery clamp (that part that connects to the battery post) completely solved this problem.

I also have a 06 CS with the same issue... to make sure it was the sensor I hooked it up to one of our diagnostic tools to check the live stream but I found that the temperature of the coolant was not low?!? In fact it was reaching 93 degrees Celsius while running idle in one spot and the temperature outside was only 61 degrees Fahrenheit . Could the temperature sensor still be at fault???

Yes you are correct. Please read the first pages of this thread you will find that the temp sensor can cause this problem. I had mine replaced and it fixed the issue with slow cranking while the engine is hot or after spirited drives.

Hi all, I’ve just purchased an 07 Boxster S and seem to be having this same issue. I swapped the coolant sensor out but still after a long drive, if I immediately start the car again after stopping it’s slow to crank and doesn’t start. A couple of tries and it’s ok. It always starts first time from cold so clearly it’s a sensor issue somewhere. Anything else I can try? I’ve checked for errors via the obd port and there’s nothing at all. It also stalled once when idling after a long drive, but not since.

Just one more thing to add, it feels like an electrical issue perhaps. As it sounds like the starter is struggling to turn, but the battery itself was new from Porsche 2 years ago (now I have the proper paperwork this is the issue they were trying to solve, clearly it didn't, or did temporarily). Also the intermittent nature of it, possibly a bad ground or something? If anybody has had the same issue and solved it another way please let me know.