986 S problem at idle, engine won't rev and shakes, battery disconnected

[Heiko]

Wow i would not have thought that fuel could keep the engine from reving past a certain RPM unless something was restricting the flow maybe.... (fuel level low - is the gauge working correctly???) Did you drain anything out of the tank? (Did it smell strange or looks strange?)
Anyhow glad its working...

[Gorthaur]

Originally Posted by Heiko

Wow i would not have thought that fuel could keep the engine from reving past a certain RPM unless something was restricting the flow maybe.... (fuel level low - is the gauge working correctly???) Did you drain anything out of the tank? (Did it smell strange or looks strange?)
Anyhow glad its working...

Hi Heiko. Did not drain anything before refuelling. Gauge has always worked fine in the past.

Anyway, I've read on W. D.'S 101 projects that for some electric related jobs he suggests to have at least half a tank of fuel (if not more) in order to prevent the car from "misbehaving" after the battery is reconnected. I haven't got the book here with me so I cannot be very precise but I'm sure everybody here has got it and can easily check it.

[Meir]

Good news man.
You see. We all learned a new lesson.
Another day at the 986 college (or kindergarten. You choose )

[Gorthaur]

Hey guys, sorry for posing this question in this topic but I think we should consider what I came through after disconnecting the battery (even though we actually don't know whether the problem was related to bad fuel or the cluster job).

I'm going to replace the window regulator in the next weeks. Am I supposed to disconnect the battery (since I'll have to disconnect the airbag as well)? Can I do the whole job without touching the battery?

As far as I know, I should not turn ignition on with the airbag disconnected in order to prevent the correspondent light to come on on the cluster, is this right?

Thanks for your help, cheers.

G.

[Heiko]

It shouldnt do anything not disconnecting it... BUT its one of those 'play it safe' guidelines as 9 times out of 10 everything will go ok and that 10th time something will go wrong and the darn thing deploys - I would disconnect the battery (just undo the negative and fold it aside)

[Meir]

Originally Posted by Gorthaur

Hey guys, sorry for posing this question in this topic but I think we should consider what I came through after disconnecting the battery (even though we actually don't know whether the problem was related to bad fuel or the cluster job).

I'm going to replace the window regulator in the next weeks. Am I supposed to disconnect the battery (since I'll have to disconnect the airbag as well)? Can I do the whole job without touching the battery?

As far as I know, I should not turn ignition on with the airbag disconnected in order to prevent the correspondent light to come on on the cluster, is this right?

Thanks for your help, cheers.

G.

i disconnect the battery almost every time i work on the car. never had issues.
if disconnecting the airbag (i.e. steering wheel, door panels, seats), wait at least 15 minutes between battery disconnect, to airbag disconnect.
the reason for that is, the airbag system includes capacitors that keep the system alive, even if the battery is damaged (like in an accident for example).
just make sure when you disconnect the battery, that the ignition is off. in fact, better if you keep the key in your pocket this time
in some cases, when the battery was disconnected for a long time, the RPM in idle are not stable at firs star up.
you need to drive the car for a wail, so the ECU and the MAF sensor can synchronize.

[Gorthaur]

Originally Posted by Meir

i disconnect the battery almost every time i work on the car. never had issues.
if disconnecting the airbag (i.e. steering wheel, door panels, seats), wait at least 15 minutes between battery disconnect, to airbag disconnect.
the reason for that is, the airbag system includes capacitors that keep the system alive, even if the battery is damaged (like in an accident for example).
just make sure when you disconnect the battery, that the ignition is off. in fact, better if you keep the key in your pocket this time
in some cases, when the battery was disconnected for a long time, the RPM in idle are not stable at firs star up.
you need to drive the car for a wail, so the ECU and the MAF sensor can synchronize.

Thanks Heiko. Good point.

Thanks Meir. The question is: my car features the optional alam. Will keeping the key in my pocket and disconnecting the battery activate the alarm?

[Meir]

MOST IMPORTANT!!!
if you are disconnecting the battery, make sure to put something in the frank latch.
i used a rag, to prevent the frank from locking.
now i just moved the emergency cable to the right air vent so it is more accessible.

[Meir]

Originally Posted by Gorthaur

Thanks Heiko. Good point.

Thanks Meir. The question is: my car features the optional alam. Will keeping the key in my pocket and disconnecting the battery activate the alarm?

i have the alarm as well. it doesn't' have a back up battery (at least in the US version), so no problem with that.

[Gorthaur]

Originally Posted by Meir

i have the alarm as well. it doesn't' have a back up battery (at least in the US version), so no problem with that.

I read somewhere the EU cars differ from the US cars right on that...

For "frank" do you mean the front trunk?

[Meir]

Originally Posted by Gorthaur

I read somewhere the EU cars differ from the US cars right on that...

For "frank" do you mean the front trunk?

front trunk = frank

as for the alarm.
disconnect the battery without the ignition key on. worst case the horn will go off. you can always reconnect the battery and disarm the alarm.
if that happens, you can do what you did last time.
please let us know how it worked for you, i worked on Porsche cars for 4 years, i don't recall any spacial behavior with the "European" style"alarm system.
if you got an aftermarket alarm system, that's a different story.