3 amp current drain

[924nutter]

Hi Guys. This is proving a difficult one to trace. My 996 turbo cab has a 3 amp drain on the battery when everything is off. In the dark there are no lights on anywhere to be seen.
These may be red herrings but about 2 years ago I had a new tracker fitted but the technician did not remove the old one
2nd red herring about 5 months ago my speakers were emitting a low volume high pitched noise that stopped when I changed modes to radio, and upon investigation a little while later the cd cartridge in the Becker multichanger would not eject. I had a deeper look today and removed the multichanger. I could not get the electrical plug out of the unit but the fibre optic cable unplugged easily. Inside the unit there is one flashing led which flashes randomly and suggests there is power to the unit. I checked fuse D9 which is the sound system fuse and it is ok D8 is the radio fuse and the radio works so that is ok as well.
Disconnecting the battery and reconnecting it made no difference. I put the ammeter between the positive lead and the positive terminal on the battery and it showed a draw of a nominal 3 amps. That is much too much I would expect a draw of 0.1 to 0.2 amps. Anyone had a similar problem?

 

[Richard_Hamilton]

Try disconnecting the alternator and measuring the drain again. If it drops significantly it is probably the diode pack, which can be changed.

Strictly speaking, you should measure the drain with the car locked, after a period of 61 minutes. However, I agree the drain does sound too high under the circumstances.

See here https://www.porscheclubgb.com/forum/tm.aspx?m=964797

 

[Gordon Attar]

Further to Richard's suggestion.

Had quite a few drains over the years. Old trackers are a prime candidate. Usually have to involve the the specialists to solve who usually need to keep the car.

 

[C2dweller]

You are looking for about 0.25A. It will take a few minutes to drop to that An everything has to be locked with alarm on - so be sure to latch the bonnet catch.

Most common problem we see is PCM unit and AMP, but methodically go through fuse box removing and refitting.

Good luck.

 

[924nutter]

Thanks guys. well its not the alternator diode pack; with great respect to Richard I doubted it was, because when the engine is running the voltmeter shows 13.8 volts.
I don't usually lock the car because it is in a secure garage and it has a tracker. I am inclined to think the redundant tracker might be the culprit if leaving it locked overnigh does not perform some kind of system reset.
I had my alternator replaced at Hillcrest Specialist Cars for a total that was less than the price of a my buying an alternator and fitting it.

Hillcrest have a local starter and alternator specialist in Burghfeild and he keeps 996 alternators on the shelf. I encountered one snag that I need help with on the refit. Somehow the field current lead was tangled with a white nylon pipe and it came away from its location when I pulled the alternator out. The pipe is white and about 5mm o.d. possibly four, and goes towards the centre of the engine at its open end. The other end joins a similar pipe at some kind of tee piece. Any ideas?

 

[Geoff_Fields]

Vacuum pipe from tandem pump?

 

[924nutter]

Now you mention it, it is probably a vacuum pipe because of its wall thickness, so thanks for that, but where does the open end go? I'm a bit new on 996t

 

[Geoff_Fields]

PM me your email address and I'll send you a pdf file of vac pipes from Porsche PET

 

[Richard_Hamilton]

I think you'll find the 996T doesn't have a tandem pump. Possibly a vacuum pipe going to the throttle body.

By the way, I wasn't suggesting locking the car might reset the rogue tracker. I was saying that you have to lock the sar to be able to measure the drain correctly, as shown in the document I linked to.

 

[Geoff_Fields]

I think you'll find the 996T doesn't have a tandem pump. Possibly a vacuum pipe going to the throttle body.

According to PET it does

 

[Richard_Hamilton]

According to PET it does

Maybe I'm being special, but I'm darned if I can find it. Do you have the illustration number?

 

[Geoff_Fields]

996t 108-05

 

[Richard_Hamilton]

996t 108-05

That's the secondary air injection pump, for emissions. Not a vacuum pump.

The tandem pump was introduced on the M97 engine, driven from the end of the camshaft, and provided vacuum for the brake servo.

 

[Geoff_Fields]

I bow to your superior knowledge Richard. I assumed that all Mezger engines were the same and so based my original reply on my 997GT3. I guess what's important is for the OP to get his pipe reinstated in the correct place.

 

[924nutter]

Geoff997 I pm'd you so if you have sent the pdf files I did not get them

 

[924nutter]

Geofff997 actually I have found the pet files on jasmines site and the can be enlarged so no need but thanks for the offer
Now what is the pump next to the alternator, is it power steering air con? It seems I need to get this out of the way to see what's what
I have to ay that I am not a happy bunny about the way the alternator was replaced unless I was unlucky. None of the how to videos mention this pipe. it is just an undo pull forward and disconnect. I am reaching the grrrrr stage now

 

[Geoff_Fields]

No PM received but glad you found the files. Best wait for Richard's reply regarding your question.

 

[924nutter]

I appreciate the locking the car will not reset any tracker Richard, my hope was that I would reset any spurious signals. When I first bought the car it would go 5 maybe six weeks when it was parked less than five feet from my front door. It has always been good in this respect.
I will photo the area now that I have found the memorable place that I put the charger for the camera battery.
Oh BTW I have a Ctek that indicates that the battery is ok.

 

[wibble]

Now what is the pump next to the alternator, is it power steering air con?

My guess would be air pump left under header tank and power steering pump to right of alternator.
It might be easier to pull the airbox/throttle to gain space?

 

[924nutter]

In P.E.T. Illustration 108-05 the pipe in question is part no 900 918 005 40 position 26. I presume the 900 918 005 40 refers to the basic nylon pipe and it is supplied in lengths of 140 mm, 190 mm 245 mm and 300 mm

I connects to part number 928 573 729 03 position 30, and is tricky to locate unless you remove the throttle body and look for two black nylon pipes. By gently easing these pipes upward I was able to locate the open end of 928 573 729 03. I am going to have to super-glue the pipe into the fitting because when I try to manipulate the pipe which is very rigid because of its age it pulls out of the fitting. I made a hook to ease it out from behind the maze of pipes, it was either that or cut a couple of cables ties to route the pipe correctly which looked equally awkward to replace, but I will have it all buttoned up sometime over the weekend. Thanks for all your posts