obc upgrade

[PABLO]

hi guys, i was planning to upgrade my e34 520i 1989 that comes with the analoge clock for an obc. But i read in brunos site that there are two types of obc. I dont know what is the correct obc, that will function in my car. Can you help me? i saw that on ebay they are selling some obc. Will they work in my car? Can i buy it and then make some changes so it would work in my car?
I will really preciate your information.
Thanks
Pablo

[Geoff Hoad]

There are two types. The first is a basic unit which records outside temperature, time date and has an ice warning. The second has all this plus a load of other features such as fuel consumption, range etc. Be very careful about retrofitting an OBC to your car, especially if you don't already have one. 520i models did not have OBC's as standard and retrofitting one is dependent upon whether the wiring harness exists. This is one feature that changed between models. The next hurdle is the in dash fitting which requires the plastic unit to be installed, otherwise its an expensive item from BMW. Next is to see whether you have the wiring to link to the outside temperature sensor. Suggest you may not. Finally, you need a coding plug to fit to the rear of the instruments to make it all work. Frankly, unless your'e rabid about having one, suggest you have a long think about it. I have the basic OBC on my car and went through this exercise myself. Needed an OBC that matched the car (and whilst they all fit some don't, especially some from early E32 models), the the coding plug and finally the new insert. Couldn't be bothered in the end even after I had pulled it all out check in and tested an OBC to make sure. Unfortunately, 520i models really got the short stick when it came to advanced features.

Hope this helps,

[myles]

A note for Geoff - I did an OBC retrofit in my father in laws Australian 94 525ia. He initially had the basic digital clock/temp unit. Only part required was the OBC, which was just a matter of getting a working OBC IV from a post 91 E34 or E32. We carefully cut the back out of the mounting section of the dash so that the deeper OBC would fit. It fits in perfectly and even still locks into place with the securing arm above the unit. The coding plug in the instrument cluster didn't require any changes. It was an easy 2 hour job and only cost AU$130 for the OBC.

Sorry I can't be any help with the 520i.

Myles

[Geoff Hoad]

Myles, that sounds like a good luck story. For some reason it all depends on the age of the car and the age of the OBC and the plug coding. If they all match then as you say, one quick cut and your'e in business. Otherwise..... :)