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Zingari
Donnington
Donnington


Joined: 25 Oct 2009
Posts: 12804
Location: Cheshire

1993 Porsche 964 Anniversary

PostPosted: Sun Mar 20, 2016 7:57 pm    Post subject: Diagnostic Help - No Electrics (at All) Reply with quote

Chums

Looking for some advice/confirmation on this one. Took the Silver Surfer out today Rolling Eyes 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 Surprised 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.
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Alfa Romeo’s 4C is everything a Italian sports-car should be: it’s gorgeous to the point of pornography, distinctive enough that nobody will ever mistake it for a Porsche, handles like it’s on rails and steers like a kart.
 
  
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grbspeedster
Montreal


Joined: 11 Nov 2007
Posts: 586
Location: Rugby


PostPosted: Sun Mar 20, 2016 8:20 pm    Post subject: Reply with quote

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
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Geoff
996 X50 turbo cab
 
  
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Zingari
Donnington
Donnington


Joined: 25 Oct 2009
Posts: 12804
Location: Cheshire

1993 Porsche 964 Anniversary

PostPosted: Sun Mar 20, 2016 8:22 pm    Post subject: Reply with quote

Geoff - Thanks but I dont think 964 have the issue you refer to Dont know
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Alfa Romeo’s 4C is everything a Italian sports-car should be: it’s gorgeous to the point of pornography, distinctive enough that nobody will ever mistake it for a Porsche, handles like it’s on rails and steers like a kart.
 
  
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Chief
Magny-Cours


Joined: 16 Sep 2010
Posts: 2725
Location: The Middle lands


PostPosted: Sun Mar 20, 2016 8:26 pm    Post subject: Reply with quote

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....
 
  
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ras62
Hockenheim


Joined: 20 Jan 2012
Posts: 640
Location: Cheshire


PostPosted: Sun Mar 20, 2016 10:14 pm    Post subject: Reply with quote

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?
 
  
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Alex
Le Mans
Le Mans


Joined: 06 Mar 2014
Posts: 16369
Location: The Ribble Valley, Lancashire

2000 Porsche 996 Carrera 4

PostPosted: Sun Mar 20, 2016 10:30 pm    Post subject: Reply with quote

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.
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2000 Manual 996 C4 Arctic Silver Convertible


 
  
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Zingari
Donnington
Donnington


Joined: 25 Oct 2009
Posts: 12804
Location: Cheshire

1993 Porsche 964 Anniversary

PostPosted: Sun Mar 20, 2016 10:40 pm    Post subject: Reply with quote

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
_________________
Alfa Romeo’s 4C is everything a Italian sports-car should be: it’s gorgeous to the point of pornography, distinctive enough that nobody will ever mistake it for a Porsche, handles like it’s on rails and steers like a kart.
 
  
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Zingari
Donnington
Donnington


Joined: 25 Oct 2009
Posts: 12804
Location: Cheshire

1993 Porsche 964 Anniversary

PostPosted: Mon Mar 21, 2016 5:16 pm    Post subject: Reply with quote

OK chums whilst I was hoovering my belly button in anticpation of ordering the parts I've had a thought Question

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
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Alfa Romeo’s 4C is everything a Italian sports-car should be: it’s gorgeous to the point of pornography, distinctive enough that nobody will ever mistake it for a Porsche, handles like it’s on rails and steers like a kart.
 
  
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Jcx
Estoril


Joined: 15 Aug 2013
Posts: 3874


2010 Porsche 997 Turbo

PostPosted: Mon Mar 21, 2016 5:37 pm    Post subject: Reply with quote

Zingari wrote:
OK chums whilst I was hoovering my belly button in anticpation of ordering the parts I've had a thought Question

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! thumbsup
 
  
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deMort
Long Beach


Joined: 21 Mar 2015
Posts: 6803
Location: Brighton


PostPosted: Mon Mar 21, 2016 6:47 pm    Post subject: Reply with quote

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 Sad
 
  
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Zingari
Donnington
Donnington


Joined: 25 Oct 2009
Posts: 12804
Location: Cheshire

1993 Porsche 964 Anniversary

PostPosted: Mon Mar 21, 2016 7:18 pm    Post subject: Reply with quote

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
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Alfa Romeo’s 4C is everything a Italian sports-car should be: it’s gorgeous to the point of pornography, distinctive enough that nobody will ever mistake it for a Porsche, handles like it’s on rails and steers like a kart.
 
  
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deMort
Long Beach


Joined: 21 Mar 2015
Posts: 6803
Location: Brighton


PostPosted: Mon Mar 21, 2016 7:29 pm    Post subject: Reply with quote

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 Smile
 
  
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Gazc2
Kyalami


Joined: 08 Nov 2003
Posts: 1929
Location: Perthshire


PostPosted: Mon Mar 21, 2016 8:31 pm    Post subject: Reply with quote

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 Very Happy
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2007 997 Turbo & 924s in progress
1990 964 C2
1989 3.2 targa
1987 3.2 Cab
1986 3.3 Turbo
1986 944 2.5 (later fitted with a 2.7 after wife went scuba diving in a flood and popped a piston through the block)
 
  
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Jcx
Estoril


Joined: 15 Aug 2013
Posts: 3874


2010 Porsche 997 Turbo

PostPosted: Mon Mar 21, 2016 8:54 pm    Post subject: Reply with quote

Gazc2 wrote:
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 Very Happy


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 Wink
 
  
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Waz
Estoril


Joined: 14 May 2011
Posts: 3504
Location: Sutton coldfield


PostPosted: Mon Mar 21, 2016 9:07 pm    Post subject: Reply with quote

Zingari wrote:
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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2004 3.6 996 C4S cab in The fast black
Cayenne turbo S in matching black 600bhp
 
  
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Zingari
Donnington
Donnington


Joined: 25 Oct 2009
Posts: 12804
Location: Cheshire

1993 Porsche 964 Anniversary

PostPosted: Wed Apr 06, 2016 6:53 pm    Post subject: Reply with quote

Before I clear some space in my lounge to mount the Silver Surfer on a onyx plinth as an ornament I've had the issue again PC

Drove it back from the service at my Indy and all was well. Parked on the drive and a few hours later car unlocked via alarm fob, ignition on (all lights) and then when I went to engage the starter motor I heard the solenoid click..............then nothing. All went dead and total power off.

Tried fiddling with the key no joy (ruled this out). Few minutes later all lights on, go to turn over, solenoid clicks then nothing - dead again PC Left a few mins repeated and then started no problem.

I've since then tried to replicate the problem but cant. Starts every time, starter cranks perfectly and 12.4v on standing battery.

I've been reading up in Streather's book and there is a 'suggestion' poor connectivity to the starter motor can cause 'all sorts of electrical issues' and wonder if the demand by the starter on the battery (via the earth strap(s)) is causing a circuit break somehow Dont know

I'm now leaning toward the battery/starter connectors so just ordered a new earth strap what

Sound about the right way to go Dont know
_________________
Alfa Romeo’s 4C is everything a Italian sports-car should be: it’s gorgeous to the point of pornography, distinctive enough that nobody will ever mistake it for a Porsche, handles like it’s on rails and steers like a kart.
 
  
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deMort
Long Beach


Joined: 21 Mar 2015
Posts: 6803
Location: Brighton


PostPosted: Wed Apr 06, 2016 7:13 pm    Post subject: Reply with quote

Well ... hmmm .. you have an engine earth strap which could well be faulty .. But .. you have a battery earth strap that would still give electric power to everything else , something is dropping the entire battery connection to everything .. after re reading posts , im still back at what on the wireing diagram shows some sort of + ve connection point that several wires come off from that feed everything , its got to be at that point i think.

The starter draws a huge amount of current so thats breaking the connection thats faulty , its just so randome is the problem .. need it to pack up , easy fix then lol

tell you what .. take a long drive to Sussex and ill drag out a voltmeter and have a look for you Smile
 
  
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Zingari
Donnington
Donnington


Joined: 25 Oct 2009
Posts: 12804
Location: Cheshire

1993 Porsche 964 Anniversary

PostPosted: Wed Apr 06, 2016 10:19 pm    Post subject: Reply with quote

Demort wrote:
.. after re reading posts , im still back at what on the wireing diagram shows some sort of + ve connection point that several wires come off from that feed everything , its got to be at that point i think.


Any ideas where this 'connection point' will be as it appears the positive wires run underneath the spare wheel and then up behind the fuel tank and I wouold expect them to go to the motherboard of the fusebox Dont know
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Alfa Romeo’s 4C is everything a Italian sports-car should be: it’s gorgeous to the point of pornography, distinctive enough that nobody will ever mistake it for a Porsche, handles like it’s on rails and steers like a kart.
 
  
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ras62
Hockenheim


Joined: 20 Jan 2012
Posts: 640
Location: Cheshire


PostPosted: Thu Apr 07, 2016 8:29 am    Post subject: Reply with quote

Positive runs straight to the starter iirc which isn't easy access. It's a common point for bad connection so worth undoing and applying copperslip on re tightening. One important point. Disconnect the battery + terminal before doing the job. A short to earth is easy to do in that tight space and will make quite a bang.
 
  
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deMort
Long Beach


Joined: 21 Mar 2015
Posts: 6803
Location: Brighton


PostPosted: Thu Apr 07, 2016 7:02 pm    Post subject: Reply with quote

Ive been looking at the wireing diagram i posted on my first post to figure out this problem , at K 50 it shows the battery and the feed wires .. off hand i dont know location but we have a 964 in atm so ill have a look tomorrow.

Im expecting though that it will be in the fuse board , the board can be pulled up to inspect underneath .. hell of a lot of wires though and do it with battery disconected if you want to look.
 
  
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