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Diagnostic Help - No Electrics (at All)

Zingari

Well-known member
Joined
25 Oct 2009
Messages
14,372
Chums

Looking for some advice/confirmation on this one. Took the Silver Surfer out today :roll: and all going well. Actually 'sort of' as there is a hesitation issue on constant throttle at steady constant speeds but I'll come to the 'big one' first.

Parked it up after a leisurely drive alarmed etc and then came to get back in. Car started fine but I 'think' I heard something like a spark/fuse blowing/electric arc behind the lower dash towards passenger side. Wasn't sure so decided to turn off and restart.

I turned the ignition off and then went to crank up - nothing :eek: No power at all to anything electrical, even the alarm not functioning. So whilst I was sat there deciding at which point I called recovery to look a right knob in Alderley Edge village I had a fiddle about under the dash just checking connections etc before going on to fuses.

After about 5mins I reinserted the key with a bit of poking it around the barrel all the lights came on and good to go.

Once I got home I tried to replicate the incident and again I ended up with no electrics but not sure what I actually did. After a few mins put the key in and tried again and all normal. On both occasions the clock had stopped for the times I had no power.

So I'm thinking

1) its an earth/battery connection issue - checked that and looked all fine

2) its a clock issue given that power is routed through the clock and might need the connections cleaning?

3) its an ignition key plug (behind the barrel) issue - but not sure this would isolate all electrical power including those that still work with ignitioni off?

Any clues? The more I think about the noise I'm thinking it's in my head, not connected or the 25 bags in change in the glove box in case I find a 993 for sale :grin:

Issue 2:

In relation to the 'rough' running. Engine seems 'hesitant' at a constant speed - hunting/surging very slightly. Tick-over is no different to usual (964 lumpy as its always been) and acceleration in all gears/range is perfect. It's only at a constant speed I can feel something. I've just gone over to super unleaded in case it was crap supermarket fuel from last time.

I was thinking fuel filter but would expect issues at idle/acceleration? Major service is due so filter/plugs etc will be changed.
 
Not sure as all electrics go but, have you looked at the bulkhead plugs. On my old SC I recall a similar incident after fueling up turned out the plugs behind carpet on bulkhead had come apart. On mine think it had three round plugs that went through bulkhead near the where the steering shaft went through bulkhead. Might not be same on 964 but worth a look. Think the connections worked loose as carpet moved
Good luck it's frustrating when you get these issues
 
Geoff - Thanks but I dont think 964 have the issue you refer to :dont know:
 
Zingers, my old chum, I would go with the ignition switch behind the key barrel. This would be my number one suspect at it controls everything. My dad had the same problem as you describe with his many years ago and no one could track it down. It was only when I had a multimeter on the fuel pump and observed it as he started the car up, that I could see the power going on and off with waggling the key in the ignition. It would effect partial load only and occasionally no power at all. just to test, I'd start the car and hold the revs up a bit as you waggle the key to see it replicates the symptoms. Just think how many times that ignition switch has be used in the life of our cars!
All the best,
Chief
P.S, I'd change out the fuel filter whilst your at it. These seem to be left untouched for years! Cheap and easy to change....
 
Another vote for ignition switch.
For the rough running, see how she runs on only one distributor at a time. Is the O2 sensor old? Is the air flow meter flap operation smooth?
 
Ignition switch on the barrel is the only moving part in all this (apart from the starter turning) so my gut feel would be the barrel. Also, do you have an immobiliser? I've always had ignition problems (and electrics) with immobilisers, especially retro fitted ones.
Even my ET4 scooter only stars 50% of the time. Take key out, replace, turn over, and bingo - starts.
 
Thanks chaps I'm hankering on it being the ignition barrel. One for picking up during the service or next weekend when I get chance.

Looking at This DIY from Pelican means I can do the back without affecting key changes etc
 
OK chums whilst I was hoovering my belly button in anticpation of ordering the parts I've had a thought :?:

Would the ingition switch failure cause a total loss of electrical power? I'm thinking here that the clock is on a cirucit completely independent of the ignition (as is the alarm) so would it deprive all these of power as well :dont know:
 
Zingari said:
OK chums whilst I was hoovering my belly button in anticpation of ordering the parts I've had a thought :?:

Would the ingition switch failure cause a total loss of electrical power? I'm thinking here that the clock is on a cirucit completely independent of the ignition (as is the alarm) so would it deprive all these of power as well :dont know:

upstairs for thinking Mister Z! :thumbs:
 
You had the car running , thought something was wrong so turned off the car and it had no electrics at that point .. so ... that means the generator was running the electrics up untill you turned it off .. there was no battery connection.

You left it a while and it restarted , my thinking is something got hot maybe the noise you herd and when cooled down restarted.

Ignition switch ?? i dont think so , at least looking at the diagram i dont , fine if it wouldn,t start etc but no electrics at all ?? no interior light , no clock etc .. not controled by the ignition switch i think , i did a bit of digging and found a partial wiring diagram , cant say if its exact for your year but its a guide.

Theres a couple of connection points that might be the fault but my gut feeling is the battery leads .. do you have a green top battery isolator on your car ? if so remove it , can you use a jump lead on the earth side to give it another earth and reproduce the fault ?


http://www.porscherepair.us/porsche-964-911-carrera4-5/images/2136_17_110-pin-dme-porsche-944.jpg


On the battery it shows 6 leads comeing from the positive side .. do you have six or just a couple that run to a connection point ?

Battery is at K 50 btw

Kind of job i love to get stuck into but afraid you miles away from me and as im dieing with man flu atm cant look up any diagrams at work :(
 
Thanks Dermot. Whilst I'm thinking the ignition is a bit iffy being so old soe changing this can be treated as preventative maintenance, like you I'm leaning toward something from the direct source of power.

I've no battery isolator and I checked the leads which are nice and tight. The earth strap is fixed well to the vehicle body. I perhaps need to play about more in that area.

I did manage to 'replicate' the incident on the drive after getting home but not sure if that was ignition key related or another coincidental bad connection given that teh clock stopped again etc :dont know:
 
I think the ignition switch has shear off bolts ? if so might be a bitch to diy.

The clock seems to be the clue but could you check and make sure you have no interior lights as well when the fault happens.

There seems to be many places the battery +ve connects to so im struggleing to thinkl of anything other than that im afraid.

Have a good look at the positive side , see if you can follow the leads a bit to see if theres some sort of connection , its also possible to lift up the main fuse board to look for burnt wireing , couple of fixings to undo but do it with the battery disconnected :)
 
Now that the siver surfer has all these problems happy to take it off your hands for the market rate of 25 bags of sand to alleviate your pain :D
 
Gazc2 said:
Now that the siver surfer has all these problems happy to take it off your hands for the market rate of 25 bags of sand to alleviate your pain :D

It doesn't need to work to look good. Just polish it up and park it in your lounge and spend all evening just staring at its beauty.

Just don't drive it... Oh wait, it doesn't go ;-)
 
Zingari said:
Thanks Dermot. Whilst I'm thinking the ignition is a bit iffy being so old soe changing this can be treated as preventative maintenance, like you I'm leaning toward something from the direct source of power.

I've no battery isolator and I checked the leads which are nice and tight. The earth strap is fixed well to the vehicle body. I perhaps need to play about more in that area.

I did manage to 'replicate' the incident on the drive after getting home but not sure if that was ignition key related or another coincidental bad connection given that teh clock stopped again etc :dont know:

Just because the earth strap is tight to the body doesn't mean it's a good connection !
Undo it clean it de-rust it and reapply, do the same at both poles on the battery,
If you don't believe me ask Infrasilver, his was the Same, whilst on tour :thumb:

Edit to check it next time it fails attach a jump lead between - and a good earth
 

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