Re: '83 533i Montronic vs later (more) (archive)

Hi, i finally got my 533i project up and running (probably put more money into it than it was ever worth)although it sounds like a jet engine on steroids due to a hole in the exhaust, and it has little acceleration especially in the lower rpms (like starting out in first gear). The car has been sitting for a couple of months, so what procedures should i go through to clean it up (fuel injectors, flush gas tank?)any ideas are appreciated, also, can i swap my computer with a chippable one from 1984? Thanks in advance,
Tom
'84 528e (soon to be sold)
'83 533i
Hello fellow 533i sucker (i mean owner) I have an 83' 533i that is white with a red interior and have some of the same complaints as you have. for the hesitation problem I found a few tricks that seemed to help. I use only premium unleaded fuel and every other fill-up I use a good fuel injector cleaner(I prefer STP) but most brands seem to do the job just as well. I have also found that Driving the car at high rates of speed for breif periods of time every once in a while seems to clear it up a bit. But just regular driving makes the most marked difference. As for the computer, I am not quite sure, although an ecu of motronic 1 designation and an ecu of motronic 1.1 designation cannot be interchanged because the earlier system has both an engine control computer and an idle control computer (prone to burn up, mine did less than two months ago at a cost of $200). I highly recommend a repair manual produced by Robert Bentley publishers, it costs about $70 but is priceless in information. Also a couple of good aftermarket mail order books are a good idea. (reccomendations- bavarian autosport "www.bavauto.com" and BMP design dont have their web address but they are on the web, just use your browser to locate them.)

Montronic from an '84 or later 535i.

First a caveat regarding everything below. My thoughts are based on what I can see in the Bentley manual schematic diagrams. There are known errors in manual. Reference an earlier post about the shift tower and the later 260/6 Getrag illustration being incorrect.

I've taken a quick glance at the Bentley manual. The Montronic 1.1 appears to be used only in 3/87 and later 528e. The Idle Control Module is used in both the '83 and '84 E28s. In 85 and later cars the Montronic has this circuitry internal to the Montronic.

I would think that it is possible to convert to a later '84 Montronic, but what are you basing the need to do this. I haven't looked into it, but the BMP catalog indicates that the '83 chip may be upgradable, but would require conversion by them, the chip can't be changed by the owner.

I've been wanting to look into this but haven't taken the time to get the ECU number off the Montronic per their instructions.

To me it appears that you could even change to a later Montronic if you wanted to take the time to do it. Easiest way would be to get the Montronic, engine harness, all sensors, possibly the underdash harness. I don't think the work would be of substantial benefit. Going to the '84 looks pretty simple though.

If you look further into this or do the conversion, let all of us on the board know what you find out.

Thanks,

Richard '83 533i

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