OS
Alan,
You have a great car from all the pictures...
What I suggest is two things:
1. measure the OS voltage after it's warmed up at idle or 1500 and again at about 3500.
Here's the scoop on what you're looking for, "The Motronic injection system fitted to BMW vehicles equipped with a Catalytic Converter implements a closed loop control system so that exhaust emissions may be reduced. Closed loop systems are equipped with an oxygen sensor which monitors the exhaust gas for oxygen content. A low oxygen level in the exhaust signifies a rich mixture. A high oxygen level in the exhaust
signifies a weak mixture. The Oxygen Sensor closed loop voltage is quite low and switches between 100 mVolts (weak) to 1.0 volt (rich).
The signal actually takes the form of a switch and switches from weak to rich at the rate of approximately 1 HZ. A digital voltmeter connected to the signal wire, would display.an average voltage of approximately 0.45 volts. In the event of OS circuit failure, the ECU substitutes a constant voltage of 0.45 volts and this should not be confused with the average voltage of 0.45
which occurs during switching from approximately 1.0 volt to 0.1 volt.
When the engine is operating under closed loop control, the OS signal causes the ECU to modify the injector pulse so that the AFR is maintained close to the stoichiometric ratio. By controlling the injection pulse, during most operating conditions, so that the air/ fuel ratio is always in a small window around the Lambda point (ie Lambda = 0.98 to 1.04), almost perfect combustion is achieved. Thus the Catalyst has less work to do and it will last longer with fewer emissions at the tail pipe. The closed loop control is implemented during engine operation at engine normal operating temperature. When the coolant temperatures is below 70° C, or the engine is at full load or is on the overrun the ECU will operate in open loop. When operating
in open loop, the ECU allows a richer or leaner AFR than the stoichiometric ratio. This prevents engine hesitation, for example, during acceleration with a wide open throttle. The OS only produces a signal when the exhaust gas, has reached a minimum temperature of approximately 300° C. In order that the OS will reach optimum operating temperature as quickly as possible after the engine has started, the OS contains a heating element. The OS heater is controlled by the ECU through an OS relay or from the fuel pump relay depending on vehicle. The ECU switches off the OS relay under certain conditions of speed and load.
Item 2: The AFM and adjustment after 1 above. You can alter the mixture somewhat by following the procedure in the link from last night. But not until it's comfirmed your running rich or lean.
I'd also suggest you check the throttle linkages/ cables for any play since it seems a slow at first by looking at the tach in your video. What rpms are you shifting at?
Do you have any info on what the previous owner did to the engine since it's an Ljet manifold running 1.3 motronic? Cam? Maybe a pic of the injectors? I beleive I heard Carl/ Lajolla did the conversion?
By the way- you have a 179 ECU or DME, that's good.
Okay, now a question for you- what did you use to punch the kickpanel speaker holes? And how is the center wired?
