MH_UK

Hope I can get some advice / comments from you helpful folks;

1)Battery....I just got back from three weeks travelling to find my battery flat as a pancake . I searched the archives and see lots of comments about how the porker's have a lot of electrics to keep going, but Im afraid I just don't buy it...My BMW 530 also sat idle for the same length of time and that started staight away....so whats the drain ???

2 Hopefully this one is nothing serious.....I have noticed a sort of buzzing vibration noise when I am in 3rd / 4th at fairly low revs...now in a normal car I would call the sensation something close to "pinking" which would signify simply that I need more revs....BUT....I scared myself by browsing the helpful archives ( I should have known better <img src="graemlins/c.gif" border="0" alt="[ouch]" /> ).....There are a lot of posts about this being indicative of DMF problems. The posts also tell you to listen for rattles from the transmission at idle....well, at idle with the clutch depressed, nothing, but as I lift my foot of the clutch I start to hear a mild rattle.....do I have anything to worry about

thanks in advance

M

Wachuko

1. Battery - normal. Car needs to be use. Two weeks without use and they go dead (some last more). Get a battery charger (the ones that plug into the lighter and keep the battery charge).

2. Humm... could be the clutch throw-out bearing

Bill Wagner

M:

About the transmission noise...it's unlikely (possible, but unlikely) that it's the DMF. You should have a LUK in yours. The symptoms you describe don't really seem like any of the symptoms I've heard about regarding DMF failure. I suppose it depends on how loud they are. As you release the clutch you will get driveline noise from any car. Unless the noise is loud I wouldn't worry about it, but all these terms are subjective.

If you have access to another 964 (Porsche club, friends, dealership, whatever) try another out and see if you hear the same sounds. Most of the people I've known who have had the DMF fail have reported pretty obvious symptoms...not subtle at all.

<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

Ade - C4 91

Hi M,

1. They really do this. Mine does. It often had to do with something not turning off (read archives from Adrian) like the boot light or the Alarm system.

2. I agree with Bill, you will have a LUK flywheel in your 93, so it's unlikely (but not impossible) that it's DMF failure. A DMF gone bad sounds like a bucket of bolts and you may not get warning that its going (I didn't get much notice when my C4 DMF failed and the gear change was still fine for the few minutes that I still drove it).

IF the noise is comming from pressing the clutch, You might suspect a failing throw out bearing, damaged Bearing fork, noisy master or slave clutch cylinder (seals) or could simply be the clutch pedal itself being a bit noisy.

A buzzing sound at 2000-3000 or so may just be an exhaust baffle plate loose - often the bolts holding them on rust and break.

Good luck.

Ade

Adrian

Dear M,
3 weeks no start is not a good idea with a 964. Especially with aftermarket alarms such as you have to have in the UK. If you have a backup battery installed the charge for this will do you in.
To dtermine if you actually have a current drain you need to connect a multimeter in series with the battery and the 964 and see what it says. This is for UK only by the way guys assuming an aftermarket alarm fitted. Figures are approximate.
More than 90ma means you have a current drain.
30-90ma means you have an aftermarket alarm fitted and 90ma means you have a charging backup battery.
8-20ma is normal.
200ma and above means one of your lamps is burning brighly. Most likely the hood/trunk/boot lid lamp. Best thing to do with this is disconnect it.

The buzzing sound is much more difficult. I think I know what you mean and this is quite normal. What it is and Americans will probably not experience this, it is the plastic bumpers vibrating. When you are at low rpms and low speed the engine labours anyway. The bumpers on the ROW 964s are hard mounted. They buzz.
If the buzzing is internal you need to get it fixed but I do not think it is. Well not yet anyway.
Ciao,
Adrian
911C4

MH_UK

Hey Guys...thanks a LOT....I think I scared myself after reading the archives, particulary regarding the DMF. Incidentally I dont know if it is the later unit, by using the actual vin number of the car it looks at though it is actually a 91 build even though it was not registered in the UK until 93.

As for the battery, I understand, I guess I just think that the drain shouldnt be that much, even with my aftermarket alarm fitted, as I said I cant understand how my BMW, that has all the bells and whistles doesnt seem to have the same drain.

Anyway...thanks I will seek out an appropriate charger and relax regarding the DMF

Those damn archives
<img src="graemlins/c.gif" border="0" alt="[ouch]" /> <img src="graemlins/c.gif" border="0" alt="[ouch]" />

Adrian

Dear M,
You should have also read in the archives on how to properly identify your model year. The 10th digit. First year of registration is irrelevant and can be quite expensive actually. If you have a 91 MY the 10th digit will be M and this model year does not have the LUK fitted at the factory. If you have a P series or 93 MY and it is a C2 you will most likely have the LUK. A C4 P series will not.
Keep an eye on the buzzing sound because the story is very different when talking 91 and 93 model years. Mind you a DMF failure is more clunky than buzzy. You will also tend to shudder a lot. On elast thing. A BMW is a BMW. A Porsche is a Porsche. They are very different. Comparing things will not bring you any piece of mind. One is a limo the other a true sports car. 964s love to kill batteries especially if the battery is not of the correct capacity,
Ciao,
Adrian
911C4

MH_UK

Thanks Adrian.....I will re-check the codes this evening when I get home.

Adrian

Dear M,
I have edited my post. I made a failure. P series is 1993 MY. Suffering from brain fade. Need a holiday.
Ciao,
Adrian
911C4

MH_UK

Adrian....I just checked, and as I suspected I am an "M" so as you point out this is the 91 model year.

Should I go back to worrying or should I take the original advised coures of action and just relax ??

M

Adrian

Just relax and enjoy the experience.
Ciao,
Adrian
911C4