Another battery drain and cold starting problem thread...UPDATE
08-10-2006, 02:44 PM
#1
Pro
Thread Starter
Another battery drain and cold starting problem thread...UPDATE
Hey All
In other threads I have been talking about my possible cold start problem and/or a possible battery drain issue but wanted to post some specifics regarding my problem(s) since it is still recurring even after a recent battery replacement which I thought solved the problem...
BACKGROUND:
--- bought car early last month and it always started right up first key turn
--- drove car 1800 miles from NJ to TX...no starting probs the whole trip
--- arrived TX and let car sit for a few days...car struggled to start but would finally run after a few key turns
--- let sit again for a few days and car would not start...it would crank but would not run...jump start it (yikes) and it finally starts
--- then replace 3yo interstate battery with a new red top optima last friday evening and car starts right up first key turn, drove car over the weekend and it started fine
--- then last nite (4 days later) go to start and no luck...car turns over but doesnt start...put battery on trickle charger and after lite goes green still doesnt start...then try to use charger "quick start" feature and still does not start...it does crank but doesnt start...
--- FYI...car passed PPI with no issues, but is overdue for a major service...wrench also mentioned it could use new caps/rotors
Initial DIAGNOSE/SOLVE process:
1) Replace DME relay with new one to eliminate that possible problem and to also have a spare (new relay will be here tomoorow)
2) Fully recharge formerly new optima red top battery (or take back to sears and try to exchange for a new one)
3) Follow posted method(s) for checking battery drain to isolate possible problem (getting new digital multimetter today)
4) Install new battery ground and a battery disconnect switch and keep disconnected when not in use...any recommendations???
5) Replace Caps and Rotors
Anything else I need to address???
Thanks for all the help
Bill
In other threads I have been talking about my possible cold start problem and/or a possible battery drain issue but wanted to post some specifics regarding my problem(s) since it is still recurring even after a recent battery replacement which I thought solved the problem...
BACKGROUND:
--- bought car early last month and it always started right up first key turn
--- drove car 1800 miles from NJ to TX...no starting probs the whole trip
--- arrived TX and let car sit for a few days...car struggled to start but would finally run after a few key turns
--- let sit again for a few days and car would not start...it would crank but would not run...jump start it (yikes) and it finally starts
--- then replace 3yo interstate battery with a new red top optima last friday evening and car starts right up first key turn, drove car over the weekend and it started fine
--- then last nite (4 days later) go to start and no luck...car turns over but doesnt start...put battery on trickle charger and after lite goes green still doesnt start...then try to use charger "quick start" feature and still does not start...it does crank but doesnt start...
--- FYI...car passed PPI with no issues, but is overdue for a major service...wrench also mentioned it could use new caps/rotors
Initial DIAGNOSE/SOLVE process:
1) Replace DME relay with new one to eliminate that possible problem and to also have a spare (new relay will be here tomoorow)
2) Fully recharge formerly new optima red top battery (or take back to sears and try to exchange for a new one)
3) Follow posted method(s) for checking battery drain to isolate possible problem (getting new digital multimetter today)
4) Install new battery ground and a battery disconnect switch and keep disconnected when not in use...any recommendations???
5) Replace Caps and Rotors
Anything else I need to address???
Thanks for all the help
Bill
Last edited by boze_man; 08-12-2006 at 09:06 PM.
08-12-2006, 09:02 PM
#3
Pro
Thread Starter
UPDATE:
1) charged battery and replaced DME replay...car started...so eliminate that issue
2) went thru process to trace a drain as per tech article: http://tech.rennlist.com/911/pdf/add...rainadrian.PDF
started with 2.1A w/trunk open and trunk lite on...I then disconnected trunk lite and played with interior lites etc...voila...what it turned out to be was the front trunk switch under the latch...it must be defective as it would get stuck open and draw current even with the latch closed...I have disconnected for the time being and now at .024A...hoorah i have attached pic of trunk switch...
3) then I went thru the fuses as well...pulling fuse 12 (clock etc) reduced it to .011A so must be that cabriolet warning lite that Jason mentioned below...
4) new multimeter would not read voltage for some reason...WTF...so will have to take back and exchange for a non defective one...my analog one would but hard to see subtle changes as i tried Adrian's voltage test at bottom of the article linked above...i couldnt tell using the analog meter if i was getting any voltage increase...so maybe my battery is not 100% after drain or maybe my alternator is going bad??? which maybe relates to my cold start jangle, chatter noise....
Now how do i check out the alternator??? anyone??? 
Thanks to all who have helped...
1) charged battery and replaced DME replay...car started...so eliminate that issue
2) went thru process to trace a drain as per tech article: http://tech.rennlist.com/911/pdf/add...rainadrian.PDF
started with 2.1A w/trunk open and trunk lite on...I then disconnected trunk lite and played with interior lites etc...voila...what it turned out to be was the front trunk switch under the latch...it must be defective as it would get stuck open and draw current even with the latch closed...I have disconnected for the time being and now at .024A...hoorah i have attached pic of trunk switch...
3) then I went thru the fuses as well...pulling fuse 12 (clock etc) reduced it to .011A so must be that cabriolet warning lite that Jason mentioned below...
Originally Posted by JasonAndreas
How much is your current drain and were you able to pinpoint it to fuse #?
One thing you can do to reduce the current drain by 10mA (which gives you an extra ~5 days) is to remove the cabriolet warning light bulb on the back of the clock. If you have a cabriolet you can get a similar reduction but it requires soldering a connection/wire from the relay to the bulb and cutting a trace on the PCB.
One thing you can do to reduce the current drain by 10mA (which gives you an extra ~5 days) is to remove the cabriolet warning light bulb on the back of the clock. If you have a cabriolet you can get a similar reduction but it requires soldering a connection/wire from the relay to the bulb and cutting a trace on the PCB.
Originally Posted by warmfuzzies
That WAV file sounds like the main fan/alternator to me, scrapping on the housing. it doesn't sound like the chain tensioners, I'd expect more jingles...if that makes any sense, if teh tensioner is loos then as the cam rotates it should have periods of looseness and tightness, it should therefore change pitch, I don't believe this one does.
my two cents.
Kevin/
my two cents.
Kevin/
Thanks to all who have helped...
08-13-2006, 12:51 AM
#5
Burning Brakes
if the car is turning over but not starting, it''s probably not the battery
08-13-2006, 02:55 PM
#6
Nordschleife Master
Its unlikely that you have a 2.1A battery drain and a bad alt . I bet that the battery and alt are fine and that now that you have tracked down the battery drain , everythings going to be fine . But then again its easy to pop a diode if the battery is disconnected while the alts spinning .
"which maybe relates to my cold start jangle, chatter noise...."
If you pull the alt belt so that the alt never spins on start up , will the noise go away ?
"which maybe relates to my cold start jangle, chatter noise...."
If you pull the alt belt so that the alt never spins on start up , will the noise go away ?
08-13-2006, 10:37 PM
#7
Technical Specialist
Rennlist
Lifetime Member
Rennlist
Lifetime Member
Another thing that is important is HOW you check for ma draw. Per Porsche, you need to fire the engine up, turn it off, and wait at least 20 minutes for the 964 CCU to stop working. Ensure that everything that might draw power is switched off, which includes the latch on the front hood (put a screwdriver in it to flip the latch or undo the wire to it). Now, here's the important part....you can't just disconnect the negative ground wire to the battery and then put a meter on it. You need to put the meter on it before disconnecting the cable. This allows you to see any drain while it's still enabled from the engine running - think relay that lets go when power is interrupted to it.
I have a drain of 350 ma when tested that way. If I disconnect the negative battery wire first, then hook up the meter, I get around 40ma (which is still a problem, but not as big an issue as 350ma drain). In my case, the CCU or one of it's components is acting up. The important point is that by measuring the ma draw as recommended by Porsche, I could easily spot the significant power drain, explaining why my battery was going flat pretty quickly.
I have a drain of 350 ma when tested that way. If I disconnect the negative battery wire first, then hook up the meter, I get around 40ma (which is still a problem, but not as big an issue as 350ma drain). In my case, the CCU or one of it's components is acting up. The important point is that by measuring the ma draw as recommended by Porsche, I could easily spot the significant power drain, explaining why my battery was going flat pretty quickly.
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08-14-2006, 01:35 AM
#8
Addict
Rennlist Member
Rennlist Member
I've had a drain for 3 years that finally got tracked down. The relay for the power windows was bad and drawing current even when off. Of course, it would be too easy if it happened all the time, so it only would be a problem when it wasn't being diagnosed (until finally...)
