obc swap question

[flyboyx]

I have a 91 318i that i am in the process of switching out the digital clock for a 13 button obc. the good news is that i have a complete donor car to scavenge parts from. the bad news is that the car is an 87 325i. I read somewhere that you have to change the chip in the obc to make it work with the 4 cyl engine. I don't have one for the 318. Anyone know where i could get this part used?

Related to the above, i really would like all of the functions to work, but i recently had someone rain on my parade when they told me that the obc cars have tons of proprietary sensors that the non obc car does not have. is there any truth to that statement? if so, how much of a pain is it to swap them over? i know of the temp sensor, perhaps one in the fuel tank..... Could it really be just as easy as plugging in the harness and the computer?

the 91 is an airbag car, which i really don't care that much about. since the 87 is not, does that mean that the turn signal stalk is not compatible? as far as the steering wheel is concerned, people say the first gen airbags can cause more injury that they prevent. Besides, i just bought an early style Momo Alpina wheel that i am dying to use. how the heck do you get the air bag off anyway? I suppose i could go on an on with the q's, but hell.....


peace!

[gearheadE30]

I'm doing the same thing you are.

1. Euro 318i M42 cars had the option of a 13 button OBC, so the code plug is still availiable. I bought mine from Pelicanparts.com, although I know that both BMAparts and bavauto can get it as well. Prices for all three sites are about the same at around $67.

2. Everything plugs into the factory body-side harness except for the code function parts. Most people who do this swap don't install the code feature, as you need another buzzer module, the factory ingnition lock from a factory 13-button car, another code box, and some other random parts. I'm not installing this in my car, but, since you have an entire parts car, you could easily swap all of the parts into the 318.

3. This is a bit of a problem. You don't need the stalk to get it to work, but the non-airbag stalk will be much closer to the wheel iirc. A new stalk is around $125, so I'd wait for one to pop up on here or just not install the stalk. It may be possible to bend the stalk, although I've never heard of anyone doing this.

Removing the airbag wheel isn't difficult, but it takes time. You need to unplug the battery and let it sit for about 30 mins to let the system discharge. There is a panel on t he bottom of the steering column; pop it open and unplug the connector. There are 4 Torx-head bolts in the back of the steering wheel that need to be unscrewed and the center airbag section pulls out. Beneath that is a large (22mm maybe) nut that has to be removed. Don't let the steering lock take the force of unbolting it; it will break. Get someone to hold the wheel. Once the nut is off, make sure the turn signal is off (you will break the pin if it isn't) and insert the key and turn it to the first position so the steering lock disengages. The wheel will be loose but will not come off if the steering lock is still on. Then, the wheel pulls off of the splines. I reccommend marking the splines so that the wheel will go back on straight.

Good luck!