Electrical gremlins - Alternator-starter cable?

Basalt_Yellow_997 · 20 Jul 2016

Hey Y'all. Hope you can assist..

2005 C2

Recently, I had the famous slow cranking issue (as well as some other electrical based problems)

After a while I also got a grinding noise from the starter and decided to change the starter

All seemed well following change... Fast cranking and healthy sounding.

However.

With the recent heat, it's starting to slow crank when hot / restarting and a few other gremlins have surfaced or resurfaced:

- spoiler hasn't gone down automatically (no light in dash, ie it wasn't me that put it up in first place)

- i have a warning light from washer fluid that seemed to disappear after installation of starter motor, that is now basically permanently on

- i have issues with my right rear Dectane LED, with check tail light warning and the light intermittently wont work (left has been fine up to now)

I experienced the spoiler and washer fluid issues before the new starter. Suddenly they resurface.

Could this all be attributed to this crap connecting cable that isn't fit for purpose? Any experience with this issue?

Voltage at alternator (or at battery when running) and battery (when not running) all seems healthy to me. Alternator is relatively new. Battery is around 5 years old.

I hear / read that the cable can corrode, but wouldn't my garage have spotted something when installing the starter? Starter went in late March / early April

Thoughts welcome..

DucatiRob · 20 Jul 2016

Can you check the battery voltage?

5 year old battery is probably at it's limits, possibly bad earth or battery cable which is a known weak point!

Basalt_Yellow_997 · 20 Jul 2016

DucatiRob said:
Can you check the battery voltage?

5 year old battery is probably at it's limits, possibly bad earth or battery cable which is a known weak point!

Yup..

Tbh just after engine off I was getting quite a high voltage through my battery like 14v. This residual alternator energy? :S

But then it settled down to 12.6 ish. I don't have a proper multimeter just a little toy thing. However my mechanic checked bat health recently and it checked out OK.

I guess its quite a small bosch battery (it doesn't fill the space). Maybe it's time for a new one

Anyone know how I can test the cable to determine for sure?

Checkmate · 21 Jul 2016

Basalt_Yellow_997 said:
Hey Y'all. Hope you can assist Thoughts welcome..

Hi

I would start from alternator-starter harnesses. I've done mine just recently and all lazy starter and electrical wired problems gone! Very Happy

On photo ( sorry for bad quality) you'll see what happen to the starter end in my car. I've picked up new one online and labour Cost me £150 with the guy that I know for years and can trust.

Anyway good luck Thumb

infrasilver · 21 Jul 2016

Check the negative to body battery earth cable, they can look fine with a visual inspection but are corroded inside the sheathing at the bulkhead sometimes only being held in place by a couple of copper strands.

Captain Lockheed · 21 Jul 2016

Speaking as a long term Mercedes driver, the first thing i do is check earths.
As an engineer, i remember reading an article in the 80's about how cars will depend on their electrics.
My experience with the 997 shows that it places a high load in the electrical system.
I don't think the OE battery is up to the job, but if you replace it you compromise the warranty.
I would clean and check earths.

Basalt_Yellow_997 · 21 Jul 2016

Thanks all for contributions

I will check earth's and get it crossed off the list

I guess my screen wash sensor and Dectane resistors might just both be gone. The rear lights do feel like they are literally cooking in 25+ degrees conditions so a resistor may have gone kaput

I'm really hoping it's not this bitch cable ðŸ˜¥

deMort · 21 Jul 2016

Its not only the starter lead .. the power distributor pole corrodes , theres a repair kit for it as its been modified from standard ( it was a crap design ) ...

http://www.suncoastparts.com/mm5/gr...yman carrera 987 997 911 battery terminal.jpg

So that needs checking.

You replaced the starter so i assume it was looked at when it was replaced .. they tend to take a long time to overheat and build up resistance so perhaps not that.

To check for any of these fault you need a voltmeter on the alternator cable , then on the battery and see how much voltage you have lost .. more than 0.6 of a volt and you have resistance somewhere .

The other faults are i feel seperate issues .

Not a cab is it ? if so check under the passenger seat for water , rear cu getting damp can cause spoiler issues.

Washer is either sensor or its empty !

Battery charge when running and at idle should be about 13.4 volts.

rear lights .. water ingress .. well known to cause faults on OE units

Basalt_Yellow_997 · 21 Jul 2016

Demort said:
Its not only the starter lead .. the power distributor pole corrodes , theres a repair kit for it as its been modified from standard ( it was a crap design ) ...

http://www.suncoastparts.com/mm5/gr...yman carrera 987 997 911 battery terminal.jpg

So that needs checking.

You replaced the starter so i assume it was looked at when it was replaced .. they tend to take a long time to overheat and build up resistance so perhaps not that.

To check for any of these fault you need a voltmeter on the alternator cable , then on the battery and see how much voltage you have lost .. more than 0.6 of a volt and you have resistance somewhere .

The other faults are i feel seperate issues .

Not a cab is it ? if so check under the passenger seat for water , rear cu getting damp can cause spoiler issues.

Washer is either sensor or its empty !

Battery charge when running and at idle should be about 13.4 volts.

rear lights .. water ingress .. well known to cause faults on OE units

Thanks for that. I'll take on board.

It's not a cab. Kinda feel like the spoiler is some kind of eleccy gremlin. Or attributable to heat, possibly..?

We filled the reservoir. You're probably right. Bad sensor.

Rear tail light I'm *hoping* is just the resistor as led / aftermarket lights tend to need a few of them in a tight, hot space.. Obvious problems ensue

I'm gonna ask my garage if they noticed anything when fitting the starter motor. Will report back

deMort · 21 Jul 2016

Im afraid im not expert on aftermarket items .. but if they use resistors then heat would indeed be an issue.

Look under the passenger seat anyways .. ive seen water bottles get stuck and split there before .. probably something else but its an easy check.

Roadcaptain! · 21 Jul 2016

I recently put up with this for approx 2 months. Slow cranking and wouldn't start when hot. I had the starter motor and cable changed and hey ho....problem solved.

Basalt_Yellow_997 · 22 Jul 2016

I did a battery check today.

"battery unstable "

Question is now.. Is this the CAUSE of the problem or a result of it? ðŸ¤”

Might I get a new battery and ***** it up due to some other ongoing problems?

I have to admit she was cranking fine today. Three quick spasmic ticks and she fired. Even after a very short trip in the heat.

Would it be best to simply change my battery and keep the fingers crossed?

Checkmate · 22 Jul 2016

Basalt_Yellow_997 said:
I did a battery check today.

"battery unstable "

Question is now.. Is this the CAUSE of the problem or a result of it? ðŸ¤”

Might I get a new battery and ***** it up due to some other ongoing problems?

I have to admit she was cranking fine today. Three quick spasmic ticks and she fired. Even after a very short trip in the heat.

Would it be best to simply change my battery and keep the fingers crossed?

I've done the same mate, bought good powerful Bosh battery and yes it help a little for few weeks. Than because of this cable I nearly demaged new battery as cable didn't transfer full charge from alternator.

Battery £80
Harnesses and labour £240

- your choice, but you have no idea what smile will come on your face when your car will start cranking like new!

Basalt_Yellow_997 · 22 Jul 2016

Checkmate said:
Basalt_Yellow_997 said:

I did a battery check today.

"battery unstable "

Question is now.. Is this the CAUSE of the problem or a result of it? ðŸ¤”

Might I get a new battery and ***** it up due to some other ongoing problems?

I have to admit she was cranking fine today. Three quick spasmic ticks and she fired. Even after a very short trip in the heat.

Would it be best to simply change my battery and keep the fingers crossed?

Click to expand...

I've done the same mate, bought good powerful Bosh battery and yes it help a little for few weeks. Than because of this cable I nearly demaged new battery as cable didn't transfer full charge from alternator.

Battery £80
Harnesses and labour £240

- your choice, but you have no idea what smile will come on your face when your car will start cranking like new!

Thing is, she IS cranking sweetly.. Most of the time.

It's just hot restarts and hot weather in general that seems to upset the car more.

Is the cable a heat-sensitive thing?

Checkmate · 22 Jul 2016

Basalt_Yellow_997 said:
Checkmate said:

Basalt_Yellow_997 said:

I did a battery check today.

"battery unstable "

Question is now.. Is this the CAUSE of the problem or a result of it? ðŸ¤”

Might I get a new battery and ***** it up due to some other ongoing problems?

I have to admit she was cranking fine today. Three quick spasmic ticks and she fired. Even after a very short trip in the heat.

Would it be best to simply change my battery and keep the fingers crossed?

Click to expand...

I've done the same mate, bought good powerful Bosh battery and yes it help a little for few weeks. Than because of this cable I nearly demaged new battery as cable didn't transfer full charge from alternator.

Battery £80
Harnesses and labour £240

- your choice, but you have no idea what smile will come on your face when your car will start cranking like new!

Click to expand...

Thing is, she IS cranking sweetly.. Most of the time.

It's just hot restarts and hot weather in general that seems to upset the car more.

Is the cable a heat-sensitive thing?

Metal it self expanding when is hot, my one was exactly the same, when hot I was preying before turn key in ignition to avoid ambaresment when cold- no problem

I'm not engineer but I think when is hot than steel connector expand end doesn't "hold" copper wires properly? Not sure mate, someone said it losing resistance - whatever that's mean ...

Electrical gremlins - Alternator-starter cable?

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