Bmw n54 12v pre-crank help

[Charlieboy]

Having some trouble with getting power to the gauge before cranking the engine. I've wired exactly as it says in the drawing for my engine but I have noticed it say 2008 on the drawing onwards and my car is a 2007.
The gauge powers up if I crank the engine but it's not what the quick start says to do.
Am I meant to wire the pre-crank power to a different wire on my car?

[Richard L]

I will look into this.

[Charlieboy]

Thanks Richard. Would it be possible to wire the 2 wires to something in the fuel box instead that runs the same kind of power?

[Richard L]

Yes, you can. I will find it for you.

[Richard L]

I cannot see any difference between the 07 and 08 model, regarding wiring.

The two red wires should be powered up at the same time as the ECU (DME). I cannot see any problem with that. The test procedure on user manual may duffer from car to car. Following the wiring diagram. You need to have the green harness connected.

[Charlieboy]

Hi Richard, finally had a bit of time today to see if I can get power to the unit before starting the engine and unfortunately 3 hours later I got no where with it.
I tried jacking into a few of the fuses but the unit won't power up on pre crack. It only powers up when the engine is started. Is it essential that the unit powers up first before the engine?

These are the steps when I start the car.

1 key card goes in and the dash light up
2 press the start button without touching the break pedal and rest of the electrics start.
3 press the start button with the break pedal down then engine starts.

I do have comfort access on my car if that makes any difference.

I managed to find a fuse that turns it on when the key isn't even in and stay on but as soon as you put the key in it turns off and won't turn back on until the engine has started.

[Richard L]

The thin red wire from the grey harness controls the aquamist's power up sequence. I really don't have an answer for you. I believe on of the wire on the DME response to keyless entry signal. Not too comfortable with that over night if a child walks near the car with a key.

Let me look into this a but further. Can you track down the 12V supply to the LP fuel pump?

[Charlieboy]

Yeah I should be able to hook it up to the lpfp 12v power supply no worries. I'll give that go and let you know how it goes.
Cheers Richard
If all else fails do you any company's that could finish off my install in the south East/ Hampshire?

[Richard L]

I would do it yourself, always end up with a better job.

It will be easier to tap it at the fuse box. I see if I have just info on file.

[Richard L]

Try FUSE 02.

[Charlieboy]

Hi Richard, I've tried tapping into the lpfp 12v wire but that only turns on once the engine has started unfortunately. I've just broke my fuse adapter so I can't try fuse 2 yet. I've ordered one and once it arrives I'll let you know how that work out. Fuse 2 say it's for the dash in my fuse booklet.
Is it essential for the controller and the gauge to power up before the engine is started? I only ask because the gauge does power up and the water level light flickers along with the flow lights if I press the accelerator. Also the green led in the controller flickers with the speed of the revs as well.

[Richard L]

There is something very wrong if the water level light flicker with flow lights.

Take a picture of the controller with all the cable plugged in.

[Charlieboy]

Hi Richard, I tried fuse 2 and it still won't power up pre crank which is weird as the dash power up once the key goes in. I've double double checked all the wiring to make sure I haven't done anything different to the drawings that came with the kit. I've got the correct drawings as well for the hsf4 3.1 which I have.
Here's a link to the photos of the controller and the gauge

http://www.aquamist.co.uk/forum/NJsL5kOm.jpg

http://www.aquamist.co.uk/forum/Ly6lFNem.jpg

Starting to lose my hair over this install lol.

[Richard L]

Two conditions for not powering up:

1. Tank level is low
2. Gauge is switched off.

Do you have a digital voltmeter? You an take some readings for me to help with the diagnostic work.