Hi - this has been discussed to length here. I also have slow starter motor when engine is warm.

I will start with the cheapest/easiest and then work my way forward. This is my prio list from what I read from you fellow 997-owners. I try to do it from cost/effort perspective starting with the easy and cheap:

1. Replace earth cord on engine
2. New battery (measure with volt meter first)
2. Replace Starter cable
3. Crank sensor replacement
4. Replace Starter motor
5. Distribution box/pin/bolt replacement (PITA to replace from what I read)
6. Replace whole battery cable harness front-back (expensive and very time consuming to replace from what I heard)

Any thoughts? Could be good if you can help me to fine-tune this list to get a proper list of order for all. Any thoughts?

 

I'll give you my experience, each is a little different based on several factors.

1. Replace earth cord on engine - I didn't know about this one. I'm assuming that is easy and inexpensive.
2. New battery (measure with volt meter first) - My battery was new already. If yours is aged it can't hurt anyway. I didn't think though issues with starting after engine warm had anything to do with the battery. It didn't with mine at least.
2. Replace Starter cable - Not easy with Tiptronic from what I could tell. I wasn't in the mood to remove my AC compressor which I'm pretty sure I would have done since I would be learning along the way.
3. Crank sensor replacement - I never considered this. Did you find history of this causing starting issues when warm?
4. Replace Starter motor - I did this, easy and cheap. Got a great new started on ebay for $125 with no core. I think I got one another Rennlister suggested. It fixed my issue. I did this change out because it seemed easier than the starter harness.
5. Distribution box/pin/bolt replacement (PITA to replace from what I read) - I didn't replace mine but I cleaned the PIN and it was easy. This did help with the crank a little.
6. Replace whole battery cable harness front-back (expensive and very time consuming to replace from what I heard) - This is what my dealer told me they would have to do for $2200!!

I didn't change your order but you can adjust if you think my info helps.

 

WhipE350 helped me debug mine as well. I first checked my battery and found that was fine. I then cleaned my distributor pin. It was corroded but cleaning it only had a small voltage improvement. I finally discovered my primary issue was parasitic drain from the new LaPower bluetooth module I recently installed. I tapped the aux power in the footwell which only shuts off when you lock the doors (I left mine unlocked in the garage). Once I figured that out the problem diminished greatly.

However my starter/alternator cable will need to be replaced at some point in the future. I get a stumble start when hot. My indy tested the voltage drop between the alternator and the battery and thats the dead giveaway if its your cable or your starter. Mine had over a .5v drop.

 

Unfortunately, #6 is the most likely candidate if it starts fine when cold, but slow after a short trip or when warm. Cold starting is harder on both the battery and starter as it's harder to push the cold oil around so neither of those is likely the issue if it starts fine when cold.

 

Recently went through his as well. My battery tested normal. We decided to check the voltage at the battery and then at the starter for any drop-off. No real voltage change observable. I had a new starter installed... problem gone. Cranks instantly, hot or cold.

 

BTW - im not sure why you would replace the entire cable (re #6). My understanding its the cable from the transmission to the starter+alternator is the offending one. Its cheap but a pain to install given you have to snake it up the back of the engine and remove the alternator, starter, AC compressor, AOS and bottom panels to get at it. My indy said the alternator can be a pain to remove the bolt holding the pulley but heat and a couple taps with a mallet (not too hard or you can break the mount) usually did the trick to break it free. One recommended removing the AOS, which is a pain but gives you more room to work. The other said he just worked around it, which is also a pain.

My indy quoted 4hrs labor, or you can tackle it yourself for $85. https://www.sonnenporscheoemparts.co...MtNmwtaDYtZ2Fz

 

Mine starts slowish also when cold. So I dont think its the cable. I have read miles about this on the forum and i would say the solutions are all over the place. Seems there is unfortunately many things that can cause it. I will anyhow go for some of the maintenance items as my car is a 2007 and things need replacing sooner or later anyway. When its cheap and ieasy I might as well do it. First I need to get a new battery for my Multimeter though

 

The issue generally is the starter alternator cable if your suffering hot start issues eg slow cranking when the engine is at temp ,,,many threads about this problem ,,,,if you are replacing the cable do the starter also why you have it all apart and access to it ...The starter can also be effected if the problem has been going on for a long period time ...........the link below is a good thread on this topic ..

https://rennlist.com/forums/997-foru...placement.html