tgavem

Resurecting a problem that has been discussed here before and was also discussed in the new Panorama magazine

If you have an early 997 and it is having difficulty starting - especially when warm - then the problem is likely the cable running to the starter & alternator. Heat and hot days make it worse. You will notice that sometimes right after running it is can be harder to start, then after it had been sitting for days.

Here is the likely problem-

The early cars (997.1) had a cable which was too small and cars will not start well eventhough the battery is fine (just now new). It is one of those pesky electrical problems because jumpstarting the car will work so it can be deceptive.

It can be as much as 8 hours of labor according to Porsche to install the new cable, but the part can be found online for around $80 and an INDY can install for about $500. Not a small job at all.

fskof

If you search there is a DIY posted with pics on how to do this job. Its not a easy job but it can be done.

kdurg

This has not been my experience at all. The car has suffered from the slow start when hot problem even AFTER replacing the alternator/starter cable. The original cable looked perfectly fine when I removed it prior to putting in a new one. There was no corrosion on the connector points and the crimp was in tact.

It was only after removing the starter itself and replacing with a new one was the problem totally eliminated. The teeth on the starter shaft were significantly worn down, combined with a lazy starter motor when hot and it would not turn the flywheel.

I urge anyone dealing with this problem to investigate the condition of their starter before incurring the added labor expense of replacing the wire harness.

dw.metro

I don't know if this is coincidental but when I changed my battery, the difficult restarting when the engine was warm seemed to go away. Anyone experience this?

AceOfAces

I had this problem about a month ago and it progressively got worse towards the end of the summer. My 997 would start up fine in the cold but when the engine was warm it would struggle to turn on. Doing some research all signs pointed to a corroded cable since we measured the voltage output from the alternator to be fine.

At the mechanics and running some tests, we decided to change the battery (was on it's 7th year) and give it a try since he says a battery going will give weird symptoms. Now everything is much better and she starts like a charm even when the engines hot.

wwest

HEAT temporarily weakends the permanant magnets in the starter motor resulting in a higher current draw from the battery and thus more voltage drop in the cable.

USMC_DS1

Had my p-dealer check the wiring harness on my CPO'd '08 C2S this summer due to slow turn over. They confirmed that my car has the newer type harness and that all voltages checked out. Conclusion... the slow turn over is normal. Hmmm. FWIW, the 2.5 yrs old battery is connected to a trickle charger every day. Looks like another DIY project I'll need to undertake... investigate the starter motor as a potential root cause.

chris.hanle

I imagine a fresh and new battery can overcome some of the cable/starter short comings, at least for a little while.

PelicanParts.com

Starter, ground cable & 12v lead can all cause similar issues if failing for whatever reason. A failing starter can slowly die over a period of time as well as die in an instant. Tricky things to diagnose. Our Starter Article provides some helpful hints for those that want to trouble shoot on their own/DIY.

Mark/Pelican Parts

CamsPorsche

Thanks for the informative thread everyone.

My 997 has been showing these signs for a month or two now and today it barely turned over even when warm. I'll have to test the battery and alternator cable leading to the battery to make sure there's no issue before committing to a new starter motor vs. cable replacement cost.

I'll update the thread as soon as I know more...

Chaos

The cable replacement fixed mine instantly...

Papa Fittig

While suffering from this issue, charging the battery would help temporarily. I am sure that a new battery will make life better for a while, however unlikely the battery is the root cause, as it would manifest itself on cold starts as well.

Anyway, the cable replacement completely fixed my issue and BTW the old cable looked like new with no signs of any corrosion, but the issue was gone.

boolala

Check the voltage drop between the alternator and battery with the car running. It should be no more than 0.5 volts. Don't know the exact number at the battery but it should probably exceed 13 v (running). If not the cable is defective and needs to be replaced.

fskof

All 997.1 (2005-2008) will have this problem. Porsche upgraded the cable for the 997.2. The replacement cable for the 997.1 is the new upgraded version so you will never have this problen again in the future.



I also read somewhere that a faulty Alternator - starter cable can damage the starter. Is this true?

wc11

Cable was too small a gauge so it suffered current limiting.
New cable solves the problem.