Which Battery

[Steve Brookes]

Colin, while pulling fuse 11 while the car is standing should be OK, the same fuse is also for the clock. Since the clock also has a number of warning lights in it, I think you will have to put the fuse back when driving it. Apparently the interior lights can be unplugged from the loom which might be a better option. I'm currently trying to find out where the plug is and will let you know if I find it.

Andy, thanks, it's good to hear that someone else thinks I might be on the right lines...as you say it's a circuit that is always live and depends on the relay to break it. I've already tried removing all the switches and the drain remained. Hopefully, the 50+ quid for a new relay will solve the problem!

 

[ras62]

Steve this thread may help, its from the 3.2 car but I presume the 964 is the same. 9th post down shows the elec schematic.

http://forums.pelicanparts.com/porsche-911-technical-forum/344722-my-electric-windows-work-without-key-ignition.html

Rob

 

[Steve Brookes]

Thanks Rob. That thread helps piece things together about the courtesy operation of the power windows. The only difference being that the 964 has one relay that combines both the courtesy function and the power to the windows. At the moment I'm scratching my head as to whether it's the relay that is the problem or if it's the interior lights that are getting an earth and causing the relay to stay powered. With my limited circuit testing skills I think I'm going to bite the bullet and get a new relay first so that I can remove that from the equation (it's the original relay as it's dated 1990) and then see what drains I have when pulling fuses, etc.

As always, nothing is simple with 964 electrics.....the aftermarket alarm fitted by the PO is plumbed into the power window circuit! [8|]

 

[ras62]

If you want to try mine to eliminate the relay drop me a mail, I'm only 10 minutes away.

 

[vitesse]

Steve,
James at Only9 at Weaverham usually has spare relays-last time I was there I aid £10 for a virtually new Fuel pump relay which as you know is common across the range.he is also prepared to "deal" if one buys several items.

 

[MarkK]

I have a standard battery in our C4 a MOLL brand that the Porsche centre fitted,i have just got them to wire up the ciggy lighter so i can charge through that to keep the battery topped up when the car is not in use.It struggled to start the other day after not being used and i wondered if it had a drain,but they have had the car in a workshop corner all week and kept an eye on it and it has held charge a treat,but at least i can keep it topped up more easily now.
Sorry if this is going slightly off thread but do other people have the "system adaption" with rear demister and foglights on( through the diagnostics port i think) on their cars done to get it to tick over stronger even when it has when warmed up?On mine if i disconnect the battery to charge it,it forgets this adaption and it has to be done again[],Porsche Leicester know about it,and Specialist cars Malton aswell,but does anyone else on here need to redo theirs when fitting a new battery or after reconnecting after charging??????(Just wondering if its a 1990 specific thing)[8|]

 

[Steve Brookes]

Mark, from what I've picked from reading posts over the years (on Rennlist in particular) C4s need adaption each time you disconnect the battery. It seems to be less of a problem with C2s. The latter will adapt better after a battery disconnect if fired up from cold and allowed to idle for several minutes with lots of electrical load - headlights on and fans blowing at high speed.

 

[Steve Brookes]

*Update on my battery drain problem*

After leaving the car for a week with the power window relay unplugged the battery was appeared to be in perfect health. So, today I put a new relay in that I had collected from Porsche yesterday (thanks Rob and Colin for your suggestions but I'd already ordered the new one before I saw your posts). With the new relay in the measured current drain was minimal at only 0.03 A (with the old relay I was sometimes seeing a drain of 0.4 A). That same 0.4 A drain is only seen with the new relay when a door is open and the interior lights are in the off position i.e. further evidence that the old relay was not shutting off power to the windows when the doors were locked.

Just to be sure I'd solved the problem, I checked the drain again with the old relay plugged in and that checked out OK too! Typical! [8|] At this stage my guess is that the old relay is OK when it's cold and then starts acting up when it warms up. I guess only time will tell on this one.

 

[NeilW]

Mark, no I've never had to do that with my '90 C4. The battery has been unplugged on numerous occasions both my myself and the bodyshop and the car runs/idles no differently. Do you know what is the adaptation compensating for?

 

[mcgc0]

Something I was wondering too... full load engine idle maybe(?)

 

[gregmarshall]

I have to say, my power window relay acts up - sometimes it chatters on and off even with the car completely off. If you try and operate the windows they stop-start. I've never been able to track the fault down....

 

[Steve Brookes]

ORIGINAL: gregmarshall

I have to say, my power window relay acts up - sometimes it chatters on and off even with the car completely off. If you try and operate the windows they stop-start. I've never been able to track the fault down....

With ignition off and doors closed the relay should cut the power to the windows. With a door open the door switch provides an earth to the relay so that the windows can be operated. So if yours is chattering (with ignition off and doors closed), my guess is that the relay is iffy or you've got a problem with a door switch.

 

[colin129]

ORIGINAL: Steve Brookes

ORIGINAL: gregmarshall

I have to say, my power window relay acts up - sometimes it chatters on and off even with the car completely off. If you try and operate the windows they stop-start. I've never been able to track the fault down....

With ignition off and doors closed the relay should cut the power to the windows. With a door open the door switch provides an earth to the relay so that the windows can be operated. So if yours is chattering (with ignition off and doors closed), my guess is that the relay is iffy or you've got a problem with a door switch.

Having recharged my battery (from completely empty, with no issues, which I have had to do on numerous occasions), I pulled fuse 11 after a Sunday blast to try to isolate the problem.

I noticed a clicking noise from the door after having locked the car up. It only happened about 4 or 5 times. When I unlocked & locked the doors again, I go the same 4 or 5 clicks. I'm was in 2 minds whether to pull the electric window fuse aswell, but that wouldn't be isolating the problem.

If the battery still empties after 4 days, like before, I'll try pulling the widow fuse instead next time.

 

[Steve Brookes]

Hi Colin, you will find out what it is much quicker if you get a multimeter and do some measurements. You can get them for about a tenner. All you need to do is undo the earth lead from the battery and use it to measure the current between the lead and the negative post on the battery. Happy to give you some pointers if you've not used one before?

First you take a baseline reading with the doors closed and then methodically pull a fuse and measure the current until you find the fuse that is associated to the drain. Ideally you want to read a current of 0.03 amps or less but that depends on what you've got wired to the bonnet switch - I now get 0.07 amps if the bonnet is open but it drops to 0.03 amps if someone holds in the switch while I measure the current.

There are some red herrings to watch out for when doing the measurements. For instance, I found that as soon as I took a reading I would get a high current draw (over 1 amp) which would drop after about 20 seconds. This was caused by the interior lights coming on and then dimming. This happened even though the doors were closed. It was caused by the courtesy relay inside the roof lining, seen here:

So I took it out:

I could then do the measurements much quicker when it wasn't interfering.

 

[Steve Brookes]

ORIGINAL: colin129


I noticed a clicking noise from the door after having locked the car up. It only happened about 4 or 5 times. When I unlocked & locked the doors again, I go the same 4 or 5 clicks. I'm was in 2 minds whether to pull the electric window fuse aswell, but that wouldn't be isolating the problem.

Just had another thought about this. Check to see if one of your window switches is stuck in the up position. If so this could lead to a clicking sound indicating that the window relay is active. It shouldn't be with the doors closed. But if it is, this would indicate that either the relay is iffy or that one of the door closure switches is earthing, leading to the relay being activated.

 

[AVI_8]

Try this for restoring a car battery.

The battery in my porsche is fine but I did this on my BMW battery which is much larger and more costly, it only cost £5 quid and though I was sceptical I thought I'd give it a try and it worked.

All you need is magnesium sulphate (Epson salt) available from a large boots outlet or online.

Here's the utube link .....

http://www.youtube.com/watch?v=X5POnMo3_EE

This won't work if the battery plates are damaged or a dead cell but for a few quid it's worth a try, alledgedly it will give a few years life to your battery ..... I thought mine was dead but now works fine ..... You may have to discharge ... recharge it a couple of times or not, I did it anyway just as an experimental process, I'm no chemist but there's a chemical reason why a battery fails and this seems to temporarily reverse the process....

Regards

 

[colin129]

So my battery went dead again, despite removing the No 11 fuse, although it seemed to last maybe a day longer.

I tried it on the conditioner, which has brought it back from the dead on many an occasion, but it seemed to be a step too far this time, it wouldn't fully charge. I thought I'd try it in the car anyway and something strange happened.

When I turned on the ignition I had bright lights, then clicks, then the lights went dim, then bright again, clicks and dim again. A few whines from the alarm siren, more whimpers really I suppose, although it could have been something else at the back as I turned it off with the key & I should still hear this whimpering sound from the back.

Obviously, its one recharge too many for the battery, it's toast now, but I'm loath to buy a battery, just for it to discharge & I still don't know where the current is leaking away from.

Anyway, new battery & a cut off switch is the first step, & once I'm running again, book in to get it sorted out.

 

[colin129]

For those of you buying a new battery, having ordered what I thought was the correct battery for my car (courtesy of Eurocarparts) and being awfully pleased with the price I paid for a Bosch battery with an 80Ah charging rate, I fine that it is 4cm wider than the current incumbent so it won't fit.

Despite it being listed as a replacement, it is designated '110', which means very big. We need batteries designated '100' to fit in the tight area available. This size of battery isn't quite as meaty either.

Real pain as I was looking forward to driving my car this weekend, I'll just have to use it twice as much next weekend instead...[8D]