Ladedruck error codes

[Stirling]

The light on my ladedruck button is flashing. Three blinks, short pause, another three blinks, long pause.

Anyone know what this means, and what other codes can also be displayed through a flashing ladedruck?

[Stirling]

Found the answer here:
http://www.m5board.com/vbulletin/alpinaboard-com-bmw-alpina-discussion/328145-e34-b10-bi-turbo-won-t-boost-above-1-1-bar.html#post4128833

Blink codes Discription

3 1 boost pressure too low
3 2 boost pressure too high
3 3 pressure sensor in control unit defective
4 1 tension/voltage on the throttle potentiometer is defective/too low
4 2 tension/voltage on the throttle switch is to high - higher than 4,3V

[Stirling]

I finally got to the bottom of this. The error lights were indicating a problem with the boost pressure control module, which is one of the four computers under the cover on the passenger side of the car under the hood, near the firewall.

It is the third module, the one with the hose running into it.

Cost for a new one from Alpina: $3100 US!

Fortunately Porsche used the same module in the 944 Turbo and Turbo S, part numbers 951.618.113.02 and 951.618.113.09 - either will work. These are available on eBay and I got one for about $250. I swapped the eprom with the one from my Alpina and voila, error message gone!

Members of the German forum alpina-forum.de were invaluable in troubleshooting this problem. You can read the full discussion here:

http://www.alpina-forum.de/forum/showthread.php?t=11623

[quattro20v]

Hi Stirling:

Glad you got that sorted, is your car driving normally now? I recall you had a boost problem before.

I've been chasing a similar problem, engine won't boost above 1.0 bar.

When you said you replaced it with a Porsche part, do you mean the whole ECU or the pressure sensor inside the ECU?

[Stirling]

I meant the ECU. The pressure sensor is supposed to be identical too I think, but the ECU I got had a different pressure sensor (maybe the previous owner changed it?). But I previously also purchased the proper pressure sensor.

I think your problem is different. I came across what you're describing on the M5board forum. Yours might be related to the instrument cluster actually.

Is the EML light on?

Is the red LED beside the Ladedruck dial lit up?

[quattro20v]

I thought mine was related to the instrument cluster too, when I saw that post on the M5board, I recall they refer to it as the "clocks" and that there was an electrical fault preventing boost.

The EML light is not on and the red LED on the ladedruck dial lights up with ignition on, but goes out after starting.

[Stirling]

So the Ladedruck light goes out and stays out for the duration of your drive?

Have you tried temporarily swapping the cluster with one from any old E34 anyway, just to be sure?

How long have you had this issue? Did it start all of a sudden? Is it intermittent?

[quattro20v]

Its been a while, but I'm pretty sure the LED light goes out when driving. I've had this issue for about 2 years now and the problem started with a hesitation under throttle, was intermittent and got worse over time. It won't boost at all and hits a wall as soon as boost comes on, at 1.0 bar, it shuts down.

I've been diagnosing this with the help of the M5board, especially Tomba who has been very helpful, but haven't managed to find the problem.

Haven't tried swapping out the cluster yet, but will give that a go, will need to find an old cluster to swap in.

[Stirling]

Check a local wrecking yard - I've been surprised by what I've been able to get for E34 locally.

You might want to try alpina-forum.de too. Very helpful folks there.

[quattro20v]

Will a standard E34 instrument cluster work?

Thanks for the tip on the German forum, will try that.

[Stirling]

My understanding is that it will. Of course it isn't a permanently solution because, among other things, the speedometer is different. But apparently it will at least allow you to confirm if the cluster is the problem.

The great thing about alpina-forum.de is, once you demonstrate your complete lack of German-speaking ability by using Google translate, they kindly tell you to write in English.:)