What is this ?

[BMWtech@mac]

So my car has had a no start problem for the last two months now and to make a long story very short I present you with this. After messing with the dme on day I figured what the hell, try and start the car. It fired right up. Few hours later tried to start again and nothing, just the same old no spark? So I moved the dme around some and tried to start again and it did. So something is loose or whatever. Took the dme out and find this box wired into it and various wire splices all over. The PO had a alarm installed as well as a new stereo head unit so the wiring harness seems to be hacked up all over. So does this white box with no markings on it belong. I'm sure it does not but just want to make sure before I go cutting stuff I don't know anything about. Also any clue on a fix or what should I do. Part of me wants to get a full un-cut harness and swap it in. Thanks for your time guys...

Christian

[e30Rob]

Can not be 100% sure on this but it appears to be what is the central comp. for the alarm. Kinda like and a processor for your computer if u know what im saying. Test and see if there is any power to said box. If not then i "personally" would trace the harness leaving the box and see where it goes.

Did u remove the alarm or is it still present? I know you said you 'had' an alarm on ther so im assuming you or the PO has removed it. Buuut you know what they say about assuming things.

[gearheadE30]

Fwiw I have never really noticed a white box like that under the dash of any e30 I've had apart, but maybe I just didn't notice it. Where was it mounted?

[Jesse30]

i have no box like that...

[BMWtech@mac]

It is wired into the dme plug and it was mounted along side of the dme, sort of just shoved in there. The alarm was half removed when I bought the car. The alarm was a immobiliser type which I guess did like a fuel and/or spark cut-off. The other thing I did notice also is that when the car is running the dme gets so hot it will almost burn you if you touch it. This can't be right, maybe a short somewhere? I hate trying to figure out what someone else did!!
Thanks for the replys guys

[kronus]

Is this the grey market mtechI car? It could be some sort of weird euro piggyback DME.

It's most likely not an alarm unit, because alarms don't give two shits about anything on the DME harness.

[e30Rob]

^^^ not to be a douche but if it is the immbolizer stlye alarm then it has fuel/spark shut down which at that point it does give to shit. If it was the non immoblizer style alarm then your quite correct.

[deutschman]

does the box have any markings or writing on it? i dont think it should be there ether. never ever seen or heard of a box like that being in a stock car.

[TexasTerp]

That is NOT a stock part. You said the alarm was "half removed" and that it was an "immobilizer". That box is the alarm computer, it has to be wired directly to the DME in order to shut down the fuel system, Also check under your steering column for a box connected to the ignition switch. Most likely you won't find anything there, since the one box is already wired to the DME.

Solution: Trace all of the wires connected to the DME and remove them at the splice. Find all of the cut wires (bypassed) and solder them back to the original DME harness (don't forget to heat shrink wrap). From the looks of it your alarm box is connected directly to the DME Plug, I can't decipher whether it is spliced or solder directly to the plug. If it soldered directly to the plug I would suggest taking it to a car audio specialist and have them remove it as it is not an easy job.

Do you have any idea what the make and model of the alarm system was?