280ZX ECU in '78 BMW

Josh Karnes joshk at tanisys.com
Tue Jun 25 15:12:14 GMT 1996


OK, I am the unfortunate owner of a BMW 530i.  As some of you may 
know, this car is notorious for:  cracking cylinder heads, lousy gas 
mileage, low power, overheating, etc.

Many of the bad things about this car can be traced to poor emission 
control design, i.e. the thermal reactors.  Here's what I have done 
to combat this so far:

1.  remove the air pump
2.  disable some other vacuum-controlled devices
3.  unplugged the cold-start injector and thermo-time switch

Information I have been able to collect indicates that the thermal 
reactor operates by running the car's mixture overrich, then 
injecting air into the massive exhaust manifold via the air pump to 
cause the abundant unburned HCs to burn, thus also reducing the 
amount of CO in the exhaust.  The thermal reactor is designed in such 
a way that it retains much heat, and this heat combined with the 
overrich fuel mixture are attributable to the problems that the car 
experiences.  By disabling the air pump, the "reaction" in the 
thermal reactor should be disabled (right?).  So, now I basically 
have a very rich-running L-Jet car.

I have recently acquired an ECU, wiring harness (python), AFM anf 
throttle position sensor from an '83 280ZX.  The 280ZX, if I am not 
mistaken, in 1983 incorporated what is essentially Bosch L-Jetrronic 
fuel injection with a Nissan-designed (probably Hitachi) digital ECU. 
 The system is closed-loop, with an O2 sensor.  What intrests me 
about this system is that it seems that I might be able to install 
the harness and ECU, plugging into existing sensors and injectors 
(including the BMW AFM, which is about twice as big) and add an O2 
sensor to create a closed-loop system, thus eliminating the overrich 
mixture.

I am certain I am missing about a million factors, so that's why I 
turn to the collective knowledge of this list.  My idea currently is 
to put a 280ZX (or other, maybe that fast-type that I just read of) 
O2 sensor in the manifold in the place where the air pump hose used 
to connect, and install the whole shebang.  Are there any comments 
out there about how compatible the components might be?  Will it be 
necessary for me to use the 280ZX AFM?  Or recalilbrate the BMW AFM?  
Can I use the BMW throttle position switch?  Will all the connectors 
simply plug right in (they appear to be the same type of connector)?

Thanks :)
_____________________________________________________________________________
Josh Karnes                                                 joshk at tanisys.com
Renaissance Man                        http://www.tanisys.com/~joshk/home.htm
Tanisys Technology                                     http://www.tanisys.com
Austin, Texas                      '78 BMW 530i | '72 Datsun 240Z | IZCC #308
_____________________________________________________________________________
           *** opinions expressed herein are MINE, ALL MINE!! ***



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