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infrasilver
Fast & Furious
Fast & Furious


Joined: 04 Oct 2010
Posts: 8002
Location: East Midlands

2001 Porsche 996 Targa

PostPosted: Wed Jan 09, 2019 10:51 pm    Post subject: Latest Fault!! Volt gauge fluctuating - A/C display flashing Reply with quote

So the last couple of months have been a PITA regarding buying parts and fixing my 996. I'm sure a lot of this is down to it not being used as much as I used to over Winter.

The first thing that happened was a failed coil pack so I bought a full set to fit along with a set of spark plugs.

A major service.

A strip down and rebuild of the O/S headlight as the indicator stopped working and a headlight reflector came loose.

My Geo needed setting after needing a couple of new front coffin arms due to a ball joint failing its MOT.

The emissions also caused problems with the MOT but I have a work around but still had to order a new vent pipe which still needs to be fitted.

My drivers door mirror motor stopped working so I bought another motor to fix that.

My O/S door was intermittently stopping the window dropping so I had to buy a new door latch.

The car became hesitant, I think a new MAF has now cleared this.

I started the car up on Monday and I got a whirring noise from the engine and after spraying a little WD-40 behind the idler pulleys it seemed these are on their way out. For this I have bought 3 new bearings to fit rather than shell out the full £70 each for the new pulleys as they went quiet after a bit of WD.

So now to today, I noticed when I was idling in the car the cars A/C unit started flashing on and off in unison with the voltage gauge on the dash rising and falling. It was rising to around 15v for a split second and dropping back to its normal position Rolling Eyes

Any Ideas what I now need to order, any usual reasons this would happen, I was thinking maybe voltage regulator but I've never had one go so I'm unsure of the symptoms Question
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kurlykris
Watkins Glen


Joined: 30 Jun 2014
Posts: 2241
Location: Warwickshire


PostPosted: Wed Jan 09, 2019 10:56 pm    Post subject: Reply with quote

Yep, voltage regulator on the alternator Sad

Have you got a code reader, you can see the voltage output on the one I have.

I think you are right, more use on a regular basis is the key to happy motoring, my 996.1 is up for MOT in March...........1000 miles driven in the last 12 months Sad
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infrasilver
Fast & Furious
Fast & Furious


Joined: 04 Oct 2010
Posts: 8002
Location: East Midlands

2001 Porsche 996 Targa

PostPosted: Wed Jan 09, 2019 11:07 pm    Post subject: Reply with quote

kurlykris wrote:
Yep, voltage regulator on the alternator Sad

Have you got a code reader, you can see the voltage output on the one I have.

I think you are right, more use on a regular basis is the key to happy motoring, my 996.1 is up for MOT in March...........1000 miles driven in the last 12 months Sad


OK thanks, I'll be plugging into it tomorrow anyway so will be going through everything. It only did it once today but I did notice my A/C unit flashing last week but didn't notice the gauge at the time. I thought nothing else of it until today, unsure with it being intermittent that it will show up as a fault?

I'll do the regulator at the same time as the idler pulley bearings I have planned to do.

I did check how many miles I have done in 2018 and I was shocked that I have probably done about 8000, I thought it was a lot less but I guess most of that was in the Summer and its only getting used sporadically at the moment in this damp cold climate, even though it's kept in the garage.
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Last edited by infrasilver on Thu Jan 10, 2019 12:29 am; edited 1 time in total
 
  
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kurlykris
Watkins Glen


Joined: 30 Jun 2014
Posts: 2241
Location: Warwickshire


PostPosted: Wed Jan 09, 2019 11:16 pm    Post subject: Reply with quote

Trying to catch an intermittent electrical fault is a PITA, it`s what I do for a living Laughing

Depends on the scan time of your code reader/pc if will actually see it or not, hence why the mention of the Pico scope in your other thread, you would see it easily with one of those Grin

My Boxster gets most of the "fun miles", I actually did 4000 in that last year Sad

My poor old Merc has to cope with 50,000 a year........................things need to change I think, Porsche for a daily driver I think Grin
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2006 Boxster S sport chrono
2010 Mercedes E350 AMG Sport

 
  
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infrasilver
Fast & Furious
Fast & Furious


Joined: 04 Oct 2010
Posts: 8002
Location: East Midlands

2001 Porsche 996 Targa

PostPosted: Sat Jan 12, 2019 7:12 pm    Post subject: Reply with quote

I have run the car today for a short while and I think my display and gauge fluctuating may be connected with my driving hesitation issue shown in my other thread.

The alternator regulator arrived today so I'll need to get this fitted to hopefully clear this problem.

This is what is happening to my dash and I also can hear the A/C fan dropping in time with this.


Open Youtube Page


And yes my LCD display does need replacing but i haven't get around to doing that particular job yet. Rolling Eyes
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Last edited by infrasilver on Sat Jan 12, 2019 7:32 pm; edited 1 time in total
 
  
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kurlykris
Watkins Glen


Joined: 30 Jun 2014
Posts: 2241
Location: Warwickshire


PostPosted: Sat Jan 12, 2019 7:30 pm    Post subject: Reply with quote

Wow, that is running rough on tickover, overcharging too, anything over 14.4V will boil the battery in a short period of time nooo
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2006 Boxster S sport chrono
2010 Mercedes E350 AMG Sport

 
  
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infrasilver
Fast & Furious
Fast & Furious


Joined: 04 Oct 2010
Posts: 8002
Location: East Midlands

2001 Porsche 996 Targa

PostPosted: Sat Jan 12, 2019 7:39 pm    Post subject: Reply with quote

kurlykris wrote:
Wow, that is running rough on tickover, overcharging too, anything over 14.4V will boil the battery in a short period of time nooo


Luckily its only intermittent but tonight it did it more than ever before, it does seem to coincide with the engine hesitating too?? I'll swap that regulator over ASAP and fingers crossed....
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kurlykris
Watkins Glen


Joined: 30 Jun 2014
Posts: 2241
Location: Warwickshire


PostPosted: Sat Jan 12, 2019 7:43 pm    Post subject: Reply with quote

Are you going to be working on it tomorrow ? I can pop up with my code reader and whatnot as I was supposed to on Thursday Thumb
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2010 Mercedes E350 AMG Sport

 
  
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infrasilver
Fast & Furious
Fast & Furious


Joined: 04 Oct 2010
Posts: 8002
Location: East Midlands

2001 Porsche 996 Targa

PostPosted: Sat Jan 12, 2019 7:51 pm    Post subject: Reply with quote

I probably won't know until tomorrow, I had been commandeered to go out for the day and I was planning on taking the 996 but I don't want to cook the electrics now.
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kurlykris
Watkins Glen


Joined: 30 Jun 2014
Posts: 2241
Location: Warwickshire


PostPosted: Sat Jan 12, 2019 8:06 pm    Post subject: Reply with quote

Yes, best not to drive it until the Voltage surge is sorted so as not to fry anything expensive. Drop me a text if you`re going to be working on it and I can pop up Thumb
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infrasilver
Fast & Furious
Fast & Furious


Joined: 04 Oct 2010
Posts: 8002
Location: East Midlands

2001 Porsche 996 Targa

PostPosted: Sat Jan 12, 2019 8:07 pm    Post subject: Reply with quote

I'll let you know in the morning. Thumb
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thecarfixer
Silverstone


Joined: 03 Nov 2016
Posts: 134



PostPosted: Sat Jan 12, 2019 9:03 pm    Post subject: Reply with quote

That voltage reg is toast. Possibly diode(s) too as there's loads of fluctuation so you're probably hitting everything with AC.

I wouldn't run that until fixed!
 
  
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infrasilver
Fast & Furious
Fast & Furious


Joined: 04 Oct 2010
Posts: 8002
Location: East Midlands

2001 Porsche 996 Targa

PostPosted: Sat Jan 12, 2019 9:20 pm    Post subject: Reply with quote

infrasilver wrote:
Could the pump be affected by the power spikes? The car ran fine tonight until the A/C unit started flashing, the engine stutters and the fans (interior and engine cooling bay) also fluctuate all in turn?


deMort wrote:
You have an electrical surgeing fault so it seems .. very strange but easy to prove .. remove the wiring from the alternator .. tape the hell out of the main power lead as you are in a world of pain if that shorts out .

Then run the car .. it wil be on the battery only .. if the fault persists then its not the alternator .

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infrasilver
Fast & Furious
Fast & Furious


Joined: 04 Oct 2010
Posts: 8002
Location: East Midlands

2001 Porsche 996 Targa

PostPosted: Sat Jan 12, 2019 9:22 pm    Post subject: Reply with quote

thecarfixer wrote:
That voltage reg is toast. Possibly diode(s) too as there's loads of fluctuation so you're probably hitting everything with AC.

I wouldn't run that until fixed!


Going to swap the regulator over first thing, I hope it's just that?
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thecarfixer
Silverstone


Joined: 03 Nov 2016
Posts: 134



PostPosted: Sat Jan 12, 2019 9:44 pm    Post subject: Reply with quote

infrasilver wrote:


Going to swap the regulator over first thing, I hope it's just that?


I'm not sure if the diode pack is separate.. Best way to check if a diode is failed is look at the output waveform (it shouldn't really be a very bumpy waveform if the diodes are working!) from the alternator.

https://www.picoauto.com/library/automotive-guided-tests/alternator-ac-ripple-diode-test/

Last edited by thecarfixer on Sat Jan 12, 2019 9:46 pm; edited 1 time in total
 
  
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kurlykris
Watkins Glen


Joined: 30 Jun 2014
Posts: 2241
Location: Warwickshire


PostPosted: Sat Jan 12, 2019 10:13 pm    Post subject: Reply with quote

thecarfixer wrote:
That voltage reg is toast. Possibly diode(s) too as there's loads of fluctuation so you're probably hitting everything with AC.

I wouldn't run that until fixed!


Yes, looking at the video it does look like the rectifier is possibly fubared too, you need to test what AC ripple is coming out of the alternator, should be below 100mv AC. It might just be the voltage regulator though and the control units are protesting on overvoltage.

Multimeter on AC setting, black lead to chassis, red lead on B+ alternator post is best, but battery + Post will show most of the ripple, but dampened by the battery, less than 100mv but 50mv is normal.

I`m thinking more and more that this is your rough running issue Chris Thumb
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2006 Boxster S sport chrono
2010 Mercedes E350 AMG Sport

 
  
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deMort
Zolder


Joined: 21 Mar 2015
Posts: 5723
Location: Brighton


PostPosted: Sun Jan 13, 2019 7:37 pm    Post subject: Reply with quote

infrasilver wrote:
infrasilver wrote:
Could the pump be affected by the power spikes? The car ran fine tonight until the A/C unit started flashing, the engine stutters and the fans (interior and engine cooling bay) also fluctuate all in turn?


deMort wrote:
You have an electrical surgeing fault so it seems .. very strange but easy to prove .. remove the wiring from the alternator .. tape the hell out of the main power lead as you are in a world of pain if that shorts out .

Then run the car .. it wil be on the battery only .. if the fault persists then its not the alternator .


very difficult for me to say .. ive not seen anything like this before so i have no real guidance ..

i still think .. you have a battery so a surgeing alternator charge rate if that is what it is would not drop the voltage below battery lvl and as such would have no bearing on the hesitation fault .

If it was a voltage fault then why are there not fault codes for pretty much every control unit .. they all need a set voltage and will generate a code if its too low .

You also have comunication between control units .. again no codes so im afraid im not convinced its the alternator .

I would be more inclined to think a battery lead or an earth lead if we are tying this hesitation fault into the a/c fault .

just replaceing the voltage reg doesnt prove its an alternator . diode pack for a start is what im thinking , this wont be replaced .. hence a disconnect of the alternator would actually prove its that or not .

Over all .. i have no answers im afraid so you would logically start by ruleing out an alternator fault then move on .

Hopefully im wrong and this is the fault though .
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infrasilver
Fast & Furious
Fast & Furious


Joined: 04 Oct 2010
Posts: 8002
Location: East Midlands

2001 Porsche 996 Targa

PostPosted: Sun Jan 13, 2019 8:38 pm    Post subject: Reply with quote

I was also thinking positive and negative leads and while I have the alternator off for the regulator I will also be cleaning and checking all the leads, I'm also going to change the bearings in the idler pulleys too while the belt is off, a lot of work to do tomorrow. I did once have an battery earth lead break/corrode and this caused the car not to start, once I fixed (bodged) the lead I was able to drive it although it didn't run well but did get me back to the hotel that night where I did a better fix.

As this seems to be intermittent its not going to be easy to pinpoint, the only thing is it does seem to be getting worse so hopefully it does this when I get the car back to my garage and not fry anything on the 3 mile drive.
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infrasilver
Fast & Furious
Fast & Furious


Joined: 04 Oct 2010
Posts: 8002
Location: East Midlands

2001 Porsche 996 Targa

PostPosted: Mon Jan 14, 2019 9:36 pm    Post subject: Reply with quote

I managed to get the new regulator fitted to the alternator today and initially I was worried about driving the car beforehand, I didn't get any power surging but the gauge was reading around 14.5 volts, maybe a little high but as it didn't surge I was happy it wasn't doing any further damage. I didn't get chance at the time to put the meter on it but I would have expected just under 16 volts going by what I found below.

When I pulled the regulator the brushes were quite worn but I'm unsure as to what point these become totally worn out.



I refitted the alternator and started the engine, I think it is better but I didn't have a chance to test drive it. I did let it run up to temperature and was seeing just under 14v on the dash and 15.07 on my meter.





So when the fans kicked in I had all the lights on full including mains and fogs also had the A/C and heated rear window running too.

It dropped to around 14.5 on my meter and just over 13v on the dash. I had no fluctuating of the lights or the engine stuttering. I'm crossing my fingers that this is cured but as we know things are never that simple.

I did also pull all the positive and negative leads and connections and cleaned them all up, they were all in good condition already and I can't see any corrosion of any of the connections or cables.

One question, where are the diodes located ar they in the regulator or another part of the alternator, just thinking ahead if this didn't cure the voltage surging problem?
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kurlykris
Watkins Glen


Joined: 30 Jun 2014
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Location: Warwickshire


PostPosted: Mon Jan 14, 2019 9:57 pm    Post subject: Reply with quote

Depends on the type of alternator Chris, looking at what you have there I would say it is a combined voltage regulator/rectifier(diode) unit, were there any other black plastic modules in the alternator after you took the rear cover off ?
Do you have a photo of the back of your alternator ?
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