997 Slow Crank (worse when hot)

Hi all, I seem to have the symptoms of a bad alternator-battery cable. Seems to be a recurring problem on 997... Typical consequences are a slow crank getting worse when hot. It's not that bad, but it clearly doesn't sound good and if it gets worse over time, then I'll start having issues to start. According to what I read, the culprit is the cable harness connecting the battery to the alternator and starter motor. It's a $100ish part, but needs a lot of labour i.e. removing air-box, throttle-box, plenum, AOS tubes, etc... My battery voltage upon idle is approx 13.7V, which seems to be low - any opinions here? What is your battery voltage on idle? Any one experience this problem? Thanks! Edited 6September, 2017 by Frenchy987

Hi Mate, Had a similar issue with my 2004 996, where it would get progressively more difficult to start after multiple stop starts. No codes being thrown but found a crank angle sensor error in memory. Replaced it and the battery at the same time and it has almost entirely eliminated the issue. I can still reproduce the slow start but I have to stop start about 6 times in a row to induce it. Car never actually fails to start though. I usually run around 14v - thought that was normal. Cheers - Jim. Edited 6September, 2017 by Jim45

I had something similar on my 944 turbo. Replaced the starter, alternator regulator and battery in that order. Replacing the old starter felt like it helped as the brushes where worn but the issue came back. put a new regulator in and still the same. Put a new battery in and the issue went away.

Had the same issue with my 996. Once the engine was warm, say a 20 odd minute drive, stop to grab a coffee and hop back in to be greeted with a slow to no crank. Replaced the starter and cable you mention and everything was working as expected. I changed both as I didn't want to pull everything apart twice. I did this a a DIY, so it is doable, but your research is accurate with what is needed to be removed. Good Luck!

First thing I would do is give the battery a full charge overnight and then see how you go. With a few shortish drives the battery will not be fully charging (batteries don't like short trips). Also take the car to one of the battery places and get them to test it (load test and the like). It may just need a good charge or be on the way out.

The A/S cable was the first thing I replaced when I bought my 997.1 S. Replaced with the updated 997.2 cable. Very common problem and talked about a lot on many other Porsche Forums.

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Thanks Sammy - did you DIY? Or have it serviced? Any idea how much they charged you for that? Talked to a mechanic at NINEAUTO (P specialist) and apparently my charge voltage of about 13.7 V on idle is nominal. 12.2 V on the battery is also normal albeit a bit low. I'm gonna get it tested before I go any further.

just another data point for a 996 - I had a slow starter as well as a loud screeching noise occaisionally after start ( the bendix gear thing wasn't working 100% of the time) Replaced the starter - didn't bother with the cable (just wire brushed the connections) and it was fine after. New starter motor is super fast, and no issues starting each and every time now.

My 06 997 S sometimes does this ....slow cranking when its hot generally summer weather ,,, short 5 minute  trip say to the servo to fill her up can result in a slow cranking starter .... at the moment the problem is not constant ,,ie it may happen a couple of times a year   ,,,I do keep my car on a trickle charger to keep the battery at full voltage ...but still have had this issue from time to time the engine does always fires up ..................if the problem becomes more constant I will look at doing the cable upgrade for the moment I can live with it ....... .

Unless the cable is too small I cannot see how it would be the issue, the short trips would be. "Easy" way to check, test the output voltage at the alternator and the battery, if there is a noticeable diff then it could be the cable. As I said short trips is not good for the battery and modern cars are very electricity hungry with all their features, sensors/ computers.

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Adam, there is a known issue on 997 and maybe 996 that the crimped connector on that A/S cable gets a bit loose and corroded with time, causing a higher electric resistance. Resistance rises with temperature, which explains why cold starts are generally OK (although they can lack a bit of authority) whereas warm starts are much longer (slower cranking). Slower warm starts generally point to a bad cable or starter motor. I've also noticed some screeching... so maybe my starter motor is going...

This thread sheds some light on the issue .. https://rennlist.com/forums/997-forum/986396-997-1-c2s-hot-start-slow-crank-finally-resolved.html corrosion on current bolt Edited 7September, 2017 by Raven

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I did come across that one... Seems to be yet another cause, this one being located closer to the battery... ___________________________________________________________ Regarding the battery, I currently have a Bosch S5 575.035 with 680CCA (75AH) Enough or weak-ish? Edited 7September, 2017 by Frenchy987

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when i I get a chance u may have a look at that on my 997 could be a possible cause for my car

also fyi, i bought a starter from amazon US. https://www.amazon.com/gp/product/B00H3R9DTM/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1 seems to work fine, fit fine on my 996, check fitment for your 997. ended up being 196AUD shipped for a new starter.

That is a good thing to know cheers ,,,,,hate to think what my dealer wants for a starter

I had a very similar issue with my 04' 996 - hard to start when warm/hot but would fire right up when cold. Turned out to be the starter cable from the alternator to the starter it would get heat soaked and then not be able to pass current. It was misdiagnosed as a bad starter but seeming your starter is making noises its most likely the culprit. I'd change both the cable and the starter. There is a voltage drop test you can do to check the cable i.e. check the voltage that the alternator is putting out and then compare it to what the starter is receiving.

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Yes agree to all of that. I plan on changing out the cable and the starter, while I'm in there. Need to equip myself with a jack, jack stands, etc. first so it'll be in a few weeks' time.

What are the starter cables generally worth .......?

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$80 or $100~ + $600 in labour but if you're replacing the starter it would be a lot less as the cable is attached to the starter but is coming out anyway.

I would do the labour  myself ,,,good on the tools and have all the gear  ............I have a feeling mine is the current bolt as the issue has only happened a few times in 3 years ,,,,,will start there and work my way back to the engine ,,,process of elimination  ...

I had the dealership do mine, however having done more work on the engine now i'd be comfortable tackling that myself. The plenum was the most difficult part, once you pass that hurdle its relatively straight forward.

yeh it's a bit daunting doing your own work at first, the secret is a super long 1/2" drive extension. http://www.supercheapauto.com.au/Product/SCA-Extension-Bar-1-2-Drive-500mm/215989 This guy has been a lifesaver. A couple of good uni joints and adapters and stuff. duct tape to tape em all together so they dont get lost in your engine and it's all good.

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Thanks for the advice. Yep, I did read about the need of a long adapter. Yours is much cheaper, thanks for the idea of buying it from an auto parts shop! Still need a bit of tooling (E12, E14 sockets), a breaker bar, and some ramps/chokes. And a helper maybe But pretty keen to tackle this one myself.

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Bunnings sell a kinchrome E-socket set and a few breaker bars too they are usually cheaper than the auto parts places on a few things. You won't need any ramps or chocks for this particular job but they are handy to have for future ones.

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Thanks Dan. So that's a question I had; are you able to access & remove aero-drag plate, the cable nuts and thread the new cable in without raising the car? yup! $36 Was planning on getting that one indeed.

Good question, having only taken apart a 996 I can't see any reason for a 996/7 to be off the ground to replace the starter + cable - which is what you're doing right?

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Yes, I would be replacing: - A/S Cable (manual transmission), Part Nr: 997 607 019 03 - Starter motor , Part Nr: 996 604 103 00 Both parts circled in red.

No need for the car to be off the ground. 1. Remove airbox 2. Remove plenum 3. Remove starter 4. Remove cable (off alternator and re route etc.) 5. Reverse steps for installation

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Sorry for the long reply (DIYing some lasagna in parallel ) Do I need to remove the A/C compressor to make room, or not needed? Does the alternator need to be removed in order to access the harness's nut? I think there are some steps missing between 3 and 4: Underneath the car: removal of the aero-drag reduction plastic cover and removal of two 10mm nuts holding the cable. How hard is it to rethread the new cable?

Just ordered a lot of Porsche Parts! - Brand new starter motor: 996 604 103 00, Brand: 'Dansk' - Cable Harness: 997 607 019 03 - 6 Spark Plugs: 999 170 223 90, Bosch FGR5KQE0 - Polyrib Belt: 996 102 151 66 - Other misc parts (Window seals, air/oil/pollen filters for next year's maintenance) Anyone heard of 'Dansk' starter motors??

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Yes there are a few things missing that don't apply to the 996, You have to remove the alternator as the cable attaches to the back of it, as for the AC compressor this might be 997 specific as the 996 has the jumper box that either needs the AC compressor to be moved or you can heat the box and it pops off. The 997 doesn't have this box.

Early Xmas cringles - got some parts in the mail this morning (but no lollies)... A new starter motor, *the* cable, a new belt (I need to remove the belt for this job, so good opportunity to change it), spark plugs (next job) and a few other parts not pictured for other restorations (other jobs): Still waiting for a few tools, and show will be on...

if ur going to do plugs..  u might as well do the coils as well. also.. drivers rear plug/coil.. have fun also can i ask where you bought the gear from? pricing good? Edited 18September, 2017 by quasio

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Howdy, Yeah, not too sure about the coils, you might be right... I was thinking of doing them, but apparently if they don't look damaged, they don't require to be changed. But you've got a point, if they look damaged when I actually remove them, would be good to have a spare set or at least a few... Pricing-wise, well it's hard to get a cheap starter motor (including shipping). My full order breaks down to this: New cable: $147 Starter: $248 (not a Bosch) Belt: $34 Bosch plugs, oil filter, oil sump crush washer, air filter, pollen filter: $145 Window gaskets, L/R: $100 Shipping: $100 -> Total of $774 incl. shipping. Payment in GBP to design911.co.uk. Shipping was very fast (3-4 days). What are your thoughts?

yeh most of my stuff i get from design911 as well, exchange rate is good for the moment. US is getting a little cheaper again, and sometimes amazon can send parts over. but i do prefer design911, as the brands are a little more known. Other options are FCP euro, they have some lifetime guarantee thing now, unsure how it works if you're in Aus, but they'll replace anything, including consumables!  like worn brakes and stuff apparently. (haven't tried) Yeh u'll probably want to change the coils too, just coz once u've done the job, u dont really want to do it again, coz it's a pain in the A$$. Note the coils i got from design911 were a different shape to the originals, but they come with the new bolts, which are a torx head (8 spanner works) instead of the allen key bolt. seem to work fine.

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Cool, thanks for the tip... I doubt they would replace used brake pads and discs though... :-) Argh $h1te... maybe I will order a half dozen coils then...

FYI... either way, they're not cheap: 6 Coils (Beru) Design911: AUD $326 inclusive of shipping. FCP-Euro: AUD $350 inclusive of shipping. MasterParts: AUD $478 inclusive of shipping. RosePassion: AUD $436 exclusive of shipping. Edited 18September, 2017 by Francois frenglish

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Apparently.. they do!.. i know it's weird, but it specifically gives that as an example..

Hi Guys :-) Just an update on this job to keep you posted... To be honest - the first attempt - I failed - (sh*t in my pants actually and abandonned!). After having removed almost everything I had to remove, I was a bit surprised by how far the starter motor and the 'infamous' cable were located and how hard the access was. Scared of doing something wrong, such as dropping and losing a part or not being able to put everything back together properly, I stopped and reassembled. I was happy when the car started again afterwards, although I hadn't fixed anything. During the weeks, that followed, I kept remembering my failure and the slow crank problem was getting worse to the point as the car refused to start last saturday after a quick wash... I had spent quite a lot of money on the parts and tooling alone, so I prepared myself for a new attempt. This time, I knew what it looked like "in real" and not through an Internet DIY and what the difficulties were: distance to the parts, difficulty to access/manipulate and - in my case - the fear of screwing things up. On the following day (Sunday) night, I started the work and spent about 6 hours on it and was able to perform the dissassembly and replacement of the two parts: starter and cable. The following night, I spent another 2 hours finishing off (reattaching the Followed a few DIYs and details that I had been reading over and over in the past couple of weeks. In a nutshell: - E-brake engaged, gear engaged, disconnect the battery, raise the car (I used ramps), chock front wheels and make sure you are working safely (isolate battery cables, chock front wheels, I even placed concrete blocks under the car in case the ramps were to fail...). - From the engine bay: remove airbox, throttle body, plenum, AOS hoses, power-steering reservoir - Remove the alternator (nightmare... Note: Pelican parts DIY article has good tips for this) - Unbolt the A/C compressor, so it can be shifted aside (no need to remove it!!) - Disconnect old cable (to replace) from alternator and old starter motor (also to replace) - Remove the 2 safety nuts from the starter motor with a super long extension (universal joints and wobble extensions are priceless for this) - Remove the starter motor by shifting it out slowly, install the new one (a pain to get the screws back in...) - Remove the 2 clips holding the old cable (a nightmare, but stick to it - it is possible) and important so you can reattach the new one like it should be. - From underneath the car, remove the two rear-most aerodynamics plates about a half dozen nuts and about 8 torx screws - Locate the cable coming from the engine bay (more or less in the middle of the car), open the little "door" and disconnect (nut) the electrical connection. Important to do this before removing the other nuts. remove the other nuts along the cable all the way up to the bottom of the engine bay. - Replace the old cable with the new one. I firmly attached the new cable to the old with some tie-wraps and pulled the old one from underneath the car. This guided the new cable through. - Reattach the 2 infamous clips (most annoying/difficult part of the job), bolt the new cable and work backwards to reinstall everything back in. - Refill your power-steering reservoir with pentosin (CHF11s, replaced by CHF202 - both can be mixed btw), reconnect the battery, hope for the best and turn the key! A few pictures of the nightmare: Only the upper part of the starter motor can be seen in the back (notice the empty space on the left where the alternator was): Old started and (engine bay side of) old cable: A few parts, that might need to go back in :-) The shiny black tube contains the new cable. The 'unbelievable' clips are before and after the 90° angle: The rotated A/C compressor: And the result.... Before (hot start after a quick wash) - not the worse case: After (4th hot start with parking lights on): As a take-away, of course, I'm extremely happy with this operation. All went well and the problem is solved. Happy with the accomplishment, being relatively inexperienced in his field but keen to learn! I was sore for the couple of days following this epic! Happy to help anyone who needs this done as well!

Nice work on the fix..........yours was really bad didn,nt want to crank at all mine is nothing like that .......good work

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Cheers, mate. I was lucky enough to diagnose the correct problem and save $300 on a new battery, which wasn't the problem. Battery is perfectly OK.

for moment I can live with mine it only seems to do it ever know and then .............these sorts of threads are good in the way that owners get to the source of the problem if you took the car to a dealer who knows how many $thousands it would cost you ..glad it all worked out

Informative thread! I'm in the process of having my workshop change the cable, starter and bolt this week after they found a fair bit of corrosion!! Recently I've been experiencing a slow crank and as it turns out, not enough volts getting to my battery (only 6 months old). After 5 days of not driving last week (coupled with only a few short 10 min trips the week before) my battery was completely dead. Hoping this fixes the issue!

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It should, I had the same issue where the cable was preventing my battery from charging.

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Difference was night and day on mine, I'm pretty sure it will be the same for you. How much did they quote for the job, if I may ask??

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Hopefully that's the case! I'm getting a few other things done as well as a major service so all up will be quite a lot. 3k + inc major service

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Doesn't sound that bad if you're getting all of that. The starter and cable alone will take 4/5 hours at least on a 997 for a really quick mechanic. For me it's more like a 7-10 hour job [emoji23] Good luck, I'm sure you'll get a great car in return [emoji4][emoji106] Sent from my iPhone using Tapatalk

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Picked it up this morning and definitely noticeable when turning the key! Car feels fresher/tighter after new plugs, filters and oil change too. Placebo probably.. just like a sh!t, shower and shave the next morning after a big night - the hangover is still there but you do feel better!

I had a slow start issue on my 996.1 gt3. Decided to replace the starter only and now car turns over much better. Would suggest anyone with start issue to check battery, check power distribution cable (positive from battery to firewall entry) for corrosion  (mine had none).. then replace starter. I'd only replace the cable if problem persisted after that point or cable connectors were loose.

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Bear?  What haven't you been telling us?

some thread revival ....................I got a new starter and a new starter alt cable ,,,so I am going to spend the day tomorrow doing the removal and replacement of both,,, fingers crossed all goes well ..

You can do it - just be patient and be ready if you need a second day. As the power-steering reservoir needs to come off, you may need to top it up prior to restarting the car (unless you carefully empty it with a syringe before removing it and refill once replaced). Operating the power-steering pump empty will damage it! Best of luck mate!

Had my self a very productive day today quite a lot to remove , but got every thing removed with out any real issues ..........reinstalled the new start motor and the new starter alt cable along with AC ,,, That rear AC bolt is a pain in the back side ,,,,,will finish the rest of tomorrow fingers cross all ends well ............ ☀️

Sounds good! Hold on tight for the first ignition!

thought I would call it a day after the AC rear bolt had to use my iphone to see were it was and make sure the E socket was seated correctly on the bolt  ,,very time consuming that rear bolt  ,,,,,I remember you said the Alternator was a nightmare but mine came out pretty easy ............I downloaded a really detailed PDF from Rennlist that covers every little detail in depth and explains methods of removal and install of each component  ,,If any one wants a copy Pm me and I can email it to you ,,,it was a big help .. The pdf is 5.05 mb

Just came back from a spirited drive ......and the change has made a huge difference ,,,as I posted earlier on in this thread my car never really suffered from this issue badly ,it did always start ,,,,,,but what a difference this has mad to the cranking speed ,,,I would say it is almost double what I had ,,,,,before the car would crank about 4 or 5 times before she fired up ,,know it is one or two very quick cranks an its alive ,,,,,,,,,,,turn it off do it again and again no issue ,,,very happy with the result and well worth the effort ,,,I think I invested around 12 hour in this but I must say I was really taking my time being OCD about every thing ,,,,,as I mentioned above if anyone wants that Pdf file and it is a real big help just contact me ......off to do some more driving ....

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How long would your old Torana's starter motor taken to change? ? Nevertheless pleased it was worth the effort on the shakedown drive.

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How about all those new cars that turn the engine off instead of idleling (?) in traffic and then start again - all to save an eyedropper of petrol. Utter madness!!! A Torana's starter motor is easy to change - but a Peugeot 505 GTI ??? 1st - lower the front end & engine & g/box away from the body and then, blah blah blah. Perfect training for the easier 997 job listed above. Seriously - well done Raven & kudos for picking a hard first job as an apprentice mechanic. Good to know it can be done at home, if I ever need to do it.

To change a starter on my old Torana Hour tops ,,,yep a lot easier than the 997 ....Like any of these jobs the first time is always a learning curve and half the drama is working out how the components come out and go back in again ,,,eg the technique,, which way to pull this or turn this to get it in or out ,,,if you had to do it a second time ,the previous experience always helps .... If you had a dealer do this ,,,it would naturally cost a lot just due to the hours involved ...I think they would charge at least 8 hrs for this job.. For anyone who wants to do the change ,,just get the correct tools listed in this thread earlier and allow yourself 2 days to just take your time and not stress about it and be patient ... It really makes a big difference and the starting of the car is now like it been hanging around Lance Armstrong

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And that included having a couple of cold stubbies ?

Double satisfaction: - having done it yourself - much faster and authoritative cranking Well done!! Really glad that it worked out well for you.

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I know this is an old post, but I did some work on a friend's 997 and he had the same problem. It would start normally when cold (the first start of the day), but when the engine was fully warmed up after a long drive, the starter would turn over very slowly or not start at all. In his case, the cable was not the problem, but he had bought a new cable based on recommendations from the Rennlist forum. Don't assume anything till you diagnose it, I say. I noted the crimps on the original cable ends were fine, but he had bought it, so I installed it. A bit of a job to install. Sure enough, nothing changed. It still cranked “slow”. By the way, I performed a load test on the battery; it was fine. Also the proper way to diagnose this is to look for a voltage drop from the source (the battery) to the load (the starter) which should be a maximum of 0.5V in a 12V system, but since he had bought the cable, he wanted it installed. Since I already had the back of the engine out and reinstalled it for the cable install, I let them take it all apart again when I said it must be the starter. They installed a new starter and while they were doing so, I disassembled the old starter and this is what I found. Just look at the commutators. I later rebuilt the starter and installed a new brush plate assembly. Runs like new and he now has a spare. Porsche 997 Starter Rebuild Depends what the ambient temperature is. Alternators are temperature compensated. On newer cars, the ECU controls the charging system. Hot = lower charge voltages. Cold = higher charge voltages. And the charge end voltage depends on the type of battery, FLA, AGM or GEL. When I got my 991, I was alarmed when I saw 14.9V-15.0V on the Multi-Information-Display. At the time I did not know the factory installed battery is an AGM and at a temperature of 6C (welcome to Canada), that is fine. Here are two charts (AGM and GEL) from East Penn Battery. On a regular FLA battery, 14.4V @ 25C or 77F.

Got this issue on my 996 GT3 and I’m hoping someone can explain to me why the starter could still be the culprit. So far I have tested the battery, it doesn’t drop below 10.3v when cranking, so assuming all good. Next I replaced the Y cable, (yay fun job) and this made no difference. Next I have stripped the starter, everything looks like new, brushes were free and it runs nicely on the bench.. What am I missing?

Not sure if its the same on the 996... BUT i had an issue with my 997 TT. There was corrosion (Garage Queen - only 46K) on a terminal that went thru the firewall..... Was intermittent - thought it was battery, then the key/ignition switch, then the cable ..... Ended up cleaning the terminal - and started first go.... It runs from the +ve cable and sits on a terminal that goes through the firewall near the battery. I'll find a link..... Simon. Edit - from post #101 https://rennlist.com/forums/997-forum/986396-997-1-c2s-hot-start-slow-crank-finally-resolved-7.html

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Thanks Simon, I’ll have a look at this and see if the 996 is the same. Definitely seems more logical than the starter at this point

Just as another data point, I had a slow crank when hot on my 2004 996 and I was very surprised to find a new battery completely cured it.  I would have thought that if the battery was marginal that it would struggle more in the cold, but not in my case.  Reading all the doom and gloom on the internet made me think I'd need Y-cable etc etc but nope.  A lot of Porsche internet content is from UK and N-E USA where they get a really hard time with corrosion, most AU cars look basically brand new underneath in comparison. I do note however multiple AU responders in this thread who did find it to be the Y-cable.  But if the battery is in any way aged, maybe just change that first as it's cheap and a two minute job.  I got an AGM Bosch battery.

Two simple tests. 1) Fully charge the disconnected battery and then let it rest overnight. Using a real load tester, apply 1/2 the  CCA of the battery for 15 seconds and note the battery voltage. Usually in the upper 9V range and the voltage is based on temperature. The higher, the better and indicates a low internal resistance of the battery. 2) Perform a voltage drop test from the Positive terminal of the battery towards the starter. Good connections have no voltage drops. During a start, the load varies so you either need a storage scope or a quality DMM with Max and Min holds. To perform this test, you need to disable the ignition circuit...so pull a fuse.

Turned out to be the starter. Bolted a new one in yesterday and all my problems have gone away 😅