So this morning my wife comes in and informs me her Cayenne wont start as she scooped up my Jag XK key and exited the building.... ok...
I went out and turned it tried to start it, very weak turning over.
Grabbed the charger and it said battery was below 20%.
Got it charged up, bought a new battery (not installed yet - another story).
Then I tried to start it again, stronger turnover, but sputtering and not starting.
I pushed the throttle to the floor during the next sputtering attempt, took a few tries but it did finally start.
Ran very rough but it ran, revved the engine from idle to 3-4k a few times.
White smoke and very very strong smell of gasoline for a few minutes.
Drove the vehicle about a block or so and back, white smoke seems to have resolved as well as the strong gasoline odor.
So with that background and the following vehicle information, here come my questions.
1996 Porsche Cayenne S (Titanium Edit), 105,000 miles
Would a low battery cause a problem with the computer engine mgmt system (ECU) causing a problem with messed up fuel air?
Could this have been a stuck injector?
I really dont want to send my wife on her way with the car if there is a good chance it will strand her, but it seems to run and start fine now.
I attached a photo of the white billowing smoke from the exhausts.
I haven't replaced the battery as I had to order the special XZN Triple Square sockets as none of my local shops carry those sockets.
Still considering changing the battery as there must be some reason it was near dead this morning, it sure seemed to charge right up to full according my battery charger.
Would a failing alternator or battery result in some sort of error code or other indication in the dummy lights?

 

Hello F15DOC,
I just posted the same issue "Initial Hard to Start and Valve Noise". I experienced similar issues last Sunday. Interesting, the 2006 Cayenne Titanium is my wife's car . Measured about 10 volts across the terminals under the hood. I installed a new battery last night. The car started fine, but a knocking noise was still present. I ran the car in idle for 20 - 30 mins this morning and the knocking went away. Also, PSM light came one, but went away after driving for a few minutes. Hopefully, changing out the battery will resolve your issue. I've heard the Cayenne don't run very well with weak batteries.

 

I just checked with my voltmeter, 14.05 volts at idle...

 

Test with the car not running. At idle the alternator is spinning

 

My point for posting the idling voltage is to state the alternator does seem to be producing electricity for recharge. The battery is back to 100% so voltage when off is 12.5V

 

Lots of short trips will drain the battery down for sure.

I bought a house 5-10 minutes away from work and there was a culmination of new circumstances that lead to needing a charger once a week.
Courtesy lights set to 90-seconds, butt-warmers both left on, driving to and from work in the dark, super short drives (compared to what was usually 1hr each way) and probably the biggest battery drain, leaving the car unlocked in the garage.
As I understand, the Canbus and Most networks remain ready to go a lot longer when the car is not locked.
In any case, alternator puts out the voltage, and I've replaced the battery on two occasions. I've decided to live with it.

 

Wow, Ok, this is the first I'm hearing of the extra battery drain due to elongated system readiness while unlocked in the garage (musta missed that in my manual)

I have a 958 & work from home. So there are many times when the CTT will sit for 3-4 days without use, & scattered usage onward.

Should I be locking it always??
TIA,

Hope you guys knock out the white smoke & battery issues!
=Steve

 

My commute is less than 10 minutes. I lock the door always, lights shut off when the car is off, seat warmers as necessary, and my battery is 7 years old with 80k miles on it. Have never needed a jump or recharge.

 

When locked, the alarm system activates and draws power. I never lock my cars when they're in the garage.
When I put my motorcycle away in the fall, it'll start right up in the spring without ever being put on a charger. If I set the alarm which also has a microwave perimeter sensor (just like the one in the Cayenne's interior), it'll run the battery FLAT in 5 days.

 

Taking this OT a bit, but hang out in your cayenne after coming to a stop and shutting it off. When not locked, you can hear electronic things working and cycling for a very long time. For me, over 45 minutes (ferry ride.) Then, do the same but this time turn off the interior detection and then lock the doors. Within about a minute it's dead silent.

This is what I have found on an 04 turbo. ymmv I suppose.

 

You either have some kind of weird draw, or you have a bad battery. My car can sit for month with the doors locked, and fire right up.

 

Has anyone let theirs sit for a month without being locked,... and had it fire right up?

Mine seems to be fine so far, after 1 years ownership, with it always unlocked in the garage (typically at most one week before driving it),... and I have had no battery problems, BUT I do not want to continue this behavior if it is hurting my battery.

And since it usually DOES matter which vintage Cayenne we're talking about / comparing,.... mine is a 958 CTT.

TIA,
=Steve

 

I used my motorcycle as an example for alarm power draw...of course a large battery will last longer.
Simple fact is, ALL alarm systems will have a constant 24/7 power drain on a battery. If someone has a marginal battery, setting the alarm isn't going to help matters.

As far as not locking the doors, I can see interior lights and side mirror lights staying on for a bit longer. I highly doubt Porsche designed a vehicle that's going to simply waste power for 45 minutes because someone didn't lock the doors.
If I had items whirring and clicking away for 45 minutes, I'd be fixing the problem. Only thing I've ever heard after shutting down the car is a faint whir from the amp fan...and that's only for a minute or two if I've had the stereo cranked.

 

This is so much fun.

We need two volunteers. 1 to test with their car locked,... hmmm, lets say for 3 months.
Next do the same, but leave it unlocked.

Thanks!!

 

One of these days I'll do an amp draw test just for fun.