Whine from engine when cold

[zcacogp]

Interesting comments, thanks chaps.

Nick - it's not that loud. It just whines a bit. OK, a reasonable bit. Interestingly, since I've sorted out the earth strap connection in the boot (see here: http://www.porscheclubgbforum.com/tm.asp?m=665683&mpage=1&key=ò£½™ ) it seems to have quietened down a fair chunk. This would suggest that it is related to electrical load and charging load ...

Bertelli,

Helpful, thanks. I'd suggest (and here I don't know the details of the charging system of a 944) that the load on the alternator is related to the electrical resistance it is presented with between the terminals. If the battery is charged then the resistance to charging is high and the current is low, hence the load on the alternator is low. If the voltage of the battery drops then the resistance to charging drops and the current goes up, meaning the alternator needs to work harder to maintain that 14.4v between the terminals. Yes, the battery should recover very quickly after starting, but when cold it takes longer and that, coupled with colder belts and greater electrical load generally (using lights, heaters, demisters, fans etc) means the load on the alternator is greater ...

At least, I think that's the argument. Whether it explains the noise made by my car remains to be seen. []

As an aside, fixing that earth strap problem has made things better all 'round; the car starts better and idles significantly more smoothly, and I'm sure it pulls better in the mid-range. I suspect that that dodgy connection caused the coil to be starved of energy and hence the sparks at the plugs to be less than they should have been.


Oli,

 

[eddieedmo]

if you think aux belt slip is causing noise just sprinkle talc on belts when engine running and if slip is a problem noise will decrease/change due to extra grip from talc.

Nick []

 

[peanut]

ORIGINAL: zcacogp

Interesting comments, thanks chaps.

Nick - it's not that loud. It just whines a bit. OK, a reasonable bit. Interestingly, since I've sorted out the earth strap connection in the boot (see here: http://www.porscheclubgbforum.com/tm.asp?m=665683&mpage=1&key=ò£½™ ) it seems to have quietened down a fair chunk. This would suggest that it is related to electrical load and charging load ...


Oli,

thats exactly what Bert suggested.[] I wasn't aware that electrical overloading could cause such a noticable noise on a car.
The boot earthing point is also for the fuel pump I believe .The most important earthing points are under the dash next to the fuse/relay tray but they are a bitch to get to.

Hows your old girl going these days Oli ? I'm really struggling to keep on top of maintenance with mine.
My whine recedes when the engine gets warm so I assumed it was somehow temperature related .

 

[zcacogp]

Nick,

The boot earthing point for the battery earth strap is only that; there is nothing other than the earth strap. (It's a fairly sizable earth too; a boss welded into the bodywork, with a hefty M8 - or maybe M10 - thread in it. The other earths may be similar - I haven't looked at them closely.) I imagine that the fuel pump also earths in the boot area, but elsewhere.

The car is OK, thanks. Sadly she is suffering slightly from lack of use; my job changed last April and she is no longer driven 40-odd miles three times a week. Being back to a 2-mile trip there-and-back, once a week, is not good for her; she doesn't run as well and is generally sulkier as a result. The usual good run over Christmas (London to Shropshire to Southampton to London to Derby and back to London) has done her a power of good and cleared some cobwebs out tho'. And improving that battery earth strap connection has helped more than I would have imagined - quite a number of niggling annoyances have been cured in the process, which is very satisfying (and has made her a LOT nicer to drive!)

Keep us posted with progress with yours. I very much look forward to news (and photos!)


Oli.

 

[peanut]

glad to hear she's still running well. They run so much better when run regularly. Mine now has a flat battery which means until I can brave the storm outside the door and run the charger out she's not even going to get her weekly warm up on the drive.

The earthing point I was referring to is the central one on the rear valance below the No plate light behind the carpet. It is also the eathing point for the rear lights I think. Poor earths are probably one of the most common source of problems on our cars .

I have been searching everywhere for all the parts needed to restore my car to mechanical magnificense and its proving a lot tougher and more expensive than expected. I have to confess I have been sneaking admiring glances at a few tasty Jaguar Mk2's and some gorgeous Mercedes 280SL []


ps. do you spend Christmas in your car ?[]

 

[zcacogp]

ORIGINAL: peanut
I have to confess I have been sneaking admiring glances at a few tasty Jaguar Mk2's and some gorgeous Mercedes 280SL []

Naughty Nick! After everyone has been offering advice, help and encouragement on getting your S2 back on the road you can't go and be unfaithful with a Jag or Merc! []

ORIGINAL: peanut
ps. do you spend Christmas in your car ?[]

No. But sometimes I wish I could ...


Oli.

 

[peanut]

ORIGINAL: zcacogp



Naughty Nick! After everyone has been offering advice, help and encouragement on getting your S2 back on the road you can't go and be unfaithful with a Jag or Merc! []


Oli.

I know but I'm really freakin out about the amount of work involved and the cost and whether the parts will fit and whether the garage will try and fleece me or damage the car etc. It was so much easier when I did my own spannering []

Wish I had a garage.[&o]

 

[zcacogp]

... and an old Merc or Mk2 Jag wouldn't present you with at least as big a maintenance headache?

If you can't trust the garage then you shouldn't be going to them. The parts, if they are the right ones, will fit.

Why can you no longer do your own spannering? You are welcome to come and use my car repair facilities, although you may find the side of a residential street in East London to be a smidge inhospitable (although that didn't stop me changing the water pump there on my S2 last December. It took a certain sense of humour to lie in a stream in the gutter in freezing conditions, but the job needed to be done.)

Stop being such a big girl's blouse! []


Oli.

 

[sulzeruk]

Ship it up to me in Scotland Nick. Would only be a couple of hundred quid. Get the train up and have a couple of days in Scotland and then drive home! I probably have most of the parts that you need and will be cheaper than anyone else labourwise!
Alasdair

 

[nick9one1]

ORIGINAL: mr brightside

ORIGINAL: zcacogp

ORIGINAL: bert gear

in winter the Altinator is working harder with all the demand on battery till it has replaced what it takes to start, hense more noise

Bert,

Really? Thanks! So it really could be nothing to worry about ...


Oli.

If Bert is right, you will hear the whine return or strengthen in amplitude when you flash the full beam or something. Assuming i've interpreted his post correctly, that is, and that he is attributing the whining to an increase in alternator output current.

I'm not one to normally disagree but it depends if the while sounds 'mechanical' or not.

The physical resistance/speed of the alternator doesn't change if more current is drawn from it. - there are no gears or connected parts inside, just a magnet and bearings that spins at the same relative speed as the engine. - So if the noise changes with speed it could be the bearings.

I would have thought this kind of noise is quite distinct from an electrical humm?

You can try the screwdiver trick which works very well!
Take a long screwdriver and while the engine is 'whining' carefully place the pointed and against a part of the engine (alternator) and the handle against your ear. You will hear the equivalent of placing your ear directly on the part the screwdriver is touching.
I would go round alternator, power steering, a/c, engine block, until you have narrowed down the part that makes the most noise.
If its not obvious keep going round until the noise disappears and see which one sounds different.

 

[peanut]

ORIGINAL: sulzeruk

Ship it up to me in Scotland Nick. Would only be a couple of hundred quid. Get the train up and have a couple of days in Scotland and then drive home! I probably have most of the parts that you need and will be cheaper than anyone else labourwise!
Alasdair

boy you don't know how tempting that sounds Alasdair ![]especially the snow and cold brrrrr [] thanks for the offer but it would cost me £hundreds to put my Dad in a care home otherwise it would be quite an adventure.

I could probably manage most of this work myself even with my bad back but my neighbours would never stand for it. They even frown upon me checking my oil and water ........ There isn't a garage to be had within 10 miles at any money.... but I do know a farmer with a barn ????? mmm might be a solution after all.

What I think I'll do is put her through an MOT and make an assessment of all the work needed before I do anything. If it needs cills and brake and fuel pipes and rear discs etc it could become a non viable project

 

[Gavin944s2]

I had a cosworth 2.5 evo 190 merc some years ago, when it developed a bit of a misfire & a stutter after a service , i tried all the local know alls before i found a enthusiast 190 cosworth lover up in Scotland , by Loch Lomond.
The spring trip & dining out on fryed mars bars []was just what i needed, to put my cosy in good hands for a proper set up. The money i saved having it done right & the peace of mind was worth every penny, not to mention the superb local hospitality. []

 

[pauljmcnulty]

What I think I'll do is put her through an MOT and make an assessment of all the work needed before I do anything. If it needs cills and brake and fuel pipes and rear discs etc it could become a non viable project

Have you got a specialist within easy reach? Or even a day-trip out?

I've found it's essential to get someone who both understands the car, and your requirements from it, to do any work if, like me, you don't or can't DIY. Saving money by knowing my annual mileage, for instance knowing a set of brake pads will see me another year where a higher-mileage car would need them replacing, whilst being able to totally trust that they won't compromise on safety, is the only way I'd ever consider running an old performance car on my very limited budget. I wish I could do the work myself, but with arthritis, no garage and very few tools it's not an option, so I have to factor in the specialist's charges every time something needs attention.

An MOT will only tell you what one person thinks about your car that day; he might well be in a bad mood, or see a "Porsche driver" with a wallet stuffed with £50s from his recent bonus. You'll not get a really honest opinion about what needs doing beyond what you know yourself, and no idea about proper costs. [8|]

 

[zcacogp]

ORIGINAL: pauljmcnulty
... arthritis ...

Crumbs. Really? I'm sorry to hear that Paul. I had you down as far, far too young to suffer from such things.

I can understand how that would affect your willingness to work on cars. I dislocated my shoulder in the summer and tore a tendon in it at the same time. If someone told me that limited movement in my shoulder would make the whole of the rest of me feel old I wouldn't have believed them. I will admit to having avoided car maintenance slightly since then ...


Oli.

 

[peanut]

sorry paul i didn't get a notification of your reply. I forget that this forum doesn't notify by default .


I have done all the work on my cars and bikes for over 35 years but in the past 10 years its been more cost effective to pay a garage do the work.
Now that I have semi-retired I have plenty of free time and the necessary finance but I do not have anywhere to do the work and I've also become so decrepid at the tender age of 60 that every little job becomes a major expedition.

I'm more than able to assess the car given sufficient information, what i cannot do is get underneath to check the chassis and brake and fuel lines and transmission, suspension and steering ,emissions, etc . An MOT is a very cheap and cost effective test and report . Whilst its up on the ramp I will go round and check everything underneath and take some HD video/stills etc.

Hopefully by tomorrow night I'll be able to make a decision on what to do and know the full extent and cost of the work involved.

 

[pauljmcnulty]

ORIGINAL: zcacogp

ORIGINAL: pauljmcnulty
... arthritis ...

Crumbs. Really? I'm sorry to hear that Paul. I had you down as far, far too young to suffer from such things.

Oli.

You say the nicest things! []

I'm actually older than I look, not 23 as most people think. []