M30 engine ECU learning

[Annddrriy]

How motronic can fix default value if O2 sensor out of range but not show up engine light and by hearing the engine sound you not need scanner to check if engine misfiring ? When operating in LOS the engine may actually run quite well with failure of one or more minor sensors. Can the engine run quite well if the ignition coil bad ?

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If ignition coil bad could all other sensors run quite well ?

[shogun]

There is no substitute value for ignition coil, only for sensors, that is clearly mentioned in the document: Limited Operating Strategy (LOS)
In the event of a serious fault in one or more of the sensors or their wiring circuits, Motronic will substitute a fixed default value in place of the defective sensor.
Ignition coil is not a sensor, if the ignition coil is bad, engine will run bad with weak sparks or not at all. If ignition coil is bad, all other sensors - if working correct - will work. They then detect for example bad exhaust gases via the O2 sensor, adjust accordingly etc pp. You MUST have a good working ignition coil. Only use quality brand ignition coils such as Bosch, Bremi, Beru ....

[Annddrriy]

I a bit mistake with reply I mean the oxygen sensor heater when disconnected it will get heat from exhaust gas and takes longer to operate properly the engine light will not illuminate on dashboard but if the oxygen sensor signal disconected from ECU pin 10 is ground or pin 28 is signal then engine light will illuminate on dashboad.

[Annddrriy]

There is substitute value for ignition coil the KV is a main substitute value for the ignition coil if KV low what RPM sensor doing that time ? Rotation of the engine is slower. The engine torque movement is low. If rotation of the engine is slower then all gases in combustion camber not completely burn out then causing oxygen sensor mulfanction properly. Compression is in the greatest condition. Cylinder head refurbished.

[shogun]

For the ignition timing the crankshaft position sensor signal is sending the signal to the DME

"If rotation of the engine is slower then all gases in combustion camber not completely burn out then causing oxygen sensor malfunction properly">>>>the O2 sensor sends a signal to the DME and adjusts all relevant items such as fuel injection time, MAF etc. The ECU is adaptive to changing engine operating characteristics and constantly monitors the data from the various sensors (ie MAP, ATS, CTS and TPS). As the engine or its components wear, the ECU reacts to new circumstances by adopting the changed values as a correction to the basic Map. When the adaptive map is used in conjunction with the OS, Motronic is able to respond much more quickly and retain tighter control over the changing gases in the exhaust system. During closed loop operation the basic injection value is determined by the values stored in the map for a specific rpm and load. If the basic injection value causes exhaust emissions outside of the Lambda value (ie 0.98 to 1.04 AFR) the mixture would be too rich or too lean and the OS would signal Motronic which in turn will correct the mixture. However, this response takes a little time and so Motronic learns a correction value and adds this 'Adaptive' values to the basic map. From now on, under most operating conditions, the emissions will be very close to Lambda and so, after reference to the OS signal, the ECU will only need to make small corrections to keep it that way. Adaption and correction of the map occurs during the following engine operations. CFSV operation, ISCV operation, Idle mixture adjustment, part load mixture adjustment.Operation of the CFSV introduces a combustible mixture to the engine that is compensated for by the fuel evaporation adaptive correction values after detection by the OS.

[Annddrriy]

For the ignition timing the crankshaft position sensor is sending the signal to the DME yes it send signal just to fire up in right time then if is KV low the ignition timing won't be right it will be lack of proper torque movement.

[Annddrriy]

Oxygen sensor did replace pins 10 with 28 then engine light ON and engine idling not smooth but consumption very low 13.1 L:100/KM and under load pistons not ringing with same gas octan. When oxygen sensor connected right way the engine light OFF but consumption very high 21.5 L:100/KM and also under load pistons ringing with same gas octan.

[Annddrriy]

When engine start cold ECU pin 23 has 0.37 volts and when engine warmed ECU pin 23 has 0.00v. I already install pin 23 in the engine ECU I will try to connect oxygen sensor ground wire to the ECU pin 23. There is no point to keep oxygen sensor heater always ON when engine is warmed.

[Annddrriy]

Oxygen sensor get heat from catalitic converter plus get heat from the heater build inside the oxygen sensor that is double heat when time to turns heater OFF in oxygen sensor it is not available of wiring connected directly to the fuel pump relay when engine is running the oxygen sensor gets heat at all time and when time to turns the oxygen sensor OFF the oxygen sensor send extra voltage to the engine ECU and engine misfire. It make sense to me. Does not make sense who has 750 series BMW because ECU pin 23 wired right through oxygen sensor relay and get grounds by the engine ECU when time to turn the oxygen sensor heater OFF the engine ECU does.

[Annddrriy]

Anyone know what voltage difference between ECU 27 and 37 they are both input voltage to ECU ?

[shogun]

no voltage shown in this diagram M1.3 https://www.e30zone.net/e30wiki/index.php/ECU_Pinouts
27 GN Start input- to ignition switch and coil from OBC
37 RD/BU Switched power from main relay

but here: Motronic 1.5 operation (note is is 1.5, not 1.3, but probably same)
Basic ECU operation
A permanent voltage supply is made from the vehicle battery to pin 18 of the ECU. This allows the self-diagnostic function to retain data of an intermittent nature. Once the ignition is switched on, a voltage supply to the ignition coil and to ECU pin 27 is made from the ignition switch. This causes the ECU to connect pin 36 to earth, so actuating the main fuel injection relay. A relay switched voltage supply is thus made to ECU pin 37, from terminal 87 of the main fuel injection relay. The majority of sensors (other than those that generate a voltage such the CAS,KS and OS), are now provided with a 5.0 volt reference supply from a relevant pin on the ECU. When the engine is cranked or run, a speed signal from the CAS causes the ECU to earth pin 3 so that the fuel pump will run. Ignition and injection functions are also activated. All actuators (Injectors, ISCV, FTVV etc),are supplied with nbv from the main relay and the ECU completes the circuit by pulsing the relevant actuator wire to earth.

Reference voltage and ECU earths Voltage supply from the ECU to many of the engine sensors is at a 5.0 volt reference level. This ensures a stable working voltage unaffected by variations in system voltage.
http://calibra-classic.org/docs/opel_motronic_1.5.pdf

Amplifier: The Motronic amplifier contains the circuitry for switching the coil negative terminal at the correct moment to instigate ignition. The signal received by the amplifier from the trigger is of an insufficient level to complete the necessary coils witching. The signal is thus amplified to a level capable of switching the coil negative terminal. The amplifier circuitry is contained within the ECU itself and the microprocessor holds a map containing the correct ignition dwell period for each condition of engine speed and battery voltage. One disadvantage of an internal amplifier, is that if the amplifier fails, the whole ECU must be renewed. Dwell operation in Motronic is based upon the principle of the constant energy current limiting' system. This means that the dwell period remains constant at around 4.0 to 5.0ms, at virtually all engine running speeds. However, the dwell duty cycle, when measured in percent or degrees, will vary as the engine speed varies. A current limiting hump is not visible when viewing an oscilloscope waveform.

Ignition coil : The ignition coil utilises low primary resistance in order to increase primary current and primary energy. The amplifier limits the primary current to around 8amps and this permits a reserve of energy to maintain the required spark burn time (duration).

[Annddrriy]

Thanks ! I will check what voltage and amperage difference between on ECU 27 and 37.

[Annddrriy]

10A multimeter scale. Multimeter will not be damaged if to loop in series between ECU pin 27 and wire just to check what amperage difference between ECU pin 27 and pin 37 when ignition is ON the engine is OFF ? Thanks in advance for your answer !

[Annddrriy]

Cylinder identification pulse generator on M30 engine. Resistance at 3-pin connector. Measured plug between pin 1 and 2 at temperature 20 C 00.5 ohm and measured insulation resistance between pin 2 and pin 3 no resistance at all. I assume cylinder identification sensor has bad insulation. How does insulation effect cylinder identification sensor to function properly ?

[shogun]

Donut/ cylinder identification resistance at 3-pin connector. Measure plug between pin 1 + 2, ≤1 ohm, insulation resistance between pin 2 + 3: ≥ 10 MOhm

I have read from some M70 owners that the cylinder identification did not work on some aftermarket ignition wires which had too much insulation, and also it did not work when the cylinder identification sensor was installed the wrong way , the sensor is a bit angled inside, correct
http://bmwe32.masscom.net/sean750/Re...WithSensor.jpg
http://bmwe32.masscom.net/sean750/Re...embledLead.jpg
above pics are from M70 http://bmwe32.masscom.net/sean750/Re...ireSet_V12.htm

Importance of functioning donuts, cyl. identification sensors M70
I just read in the German forum about a case where someone changed on his M70 distributors, rotors, spark plugs and ignition wires on cyl. 6 and 12 and used the re-old donuts. Then he had trouble. Engine starts, runs short time with increased RPM and then dies. EML lamp goes on with ignition on and then goes out again as it should be. Diagnosis faults: fault ignition cylinder 1-6 and 7-12. That was 2 weeks ago. Today he fixed it. He noticed that he installed the cylinder identification sensors/donuts/pulse generators on ignition wires cyl. 6 and 12 the wrong way. Turned the donuts the correct way and engine runs starts and smooth.
No direction marks on the original ones, if I remember correct. This is not the first time that I read that when donuts are not working properly or the ignition wires/plugs # 6 and 12 are not functioning, there will be engine problems. So if the M70 starts, idles for some seconds, then dies, also check the ignition wires, plugs and donuts from cylinder 6 and 12. The usual cause of running for a few seconds and then stopping is the lack of cylinder identification signals. These are provided by the inductive sensors on HT leads 6 and 12. When you get a fault with INPA ti-signal, this is the injection time signal, the base timing is derived from the cylinder identification signal. We had the same problem some years back on an 850: lack of cylinder identification signals. In our case the ignition wire boot of cylinder 12 was lose/not connected to the spark plug.

[Annddrriy]

insulation resistance between pin 2 + 3: ≥ 10 MOhm is not present when measured. Is that mutimeter can not pick up readings 10Mohms at multimeter scale was set on 20Mohms or this is shielding has a open circuit ? I assume this is shielding has an open circuit.

[Annddrriy]

oxygen sensor relay wiring diagram.pngMorning started the engine and looked under the car I saw steam or smoke was coming out from oxygen sensor area for 25 seconds then stop not sure what that was. I am going to install oxygen sensor relay here is a new project for 735i model which is not use oxygen sensor relay when sensor get enough heat then is not shut it OFF by the engine ECU as in 750i models. Is it going to work if to installed oxygen sensor relay ? I assume it is going to work. What do you think about ? This is not working the check engine light is on after 5 minutes.

[shogun]

I have no idea if your modification will work, you have to test and check. I would all leave as it is original since decades on your 735 M1.3 ECU. I see no technical advantage to shut off the O2 sensor on an M30 when engine is hot and cat is hot. The alternator generates enough power when engine is running to supply power to that small O2 heater.
Here it says: Heater current: This shows the current in the heater element, which is a pulse width modulation (PWM) or square wave type signal. The pulses of current start with a height of about 1.3 amps and then decline to about 0.5 amps. This is due to the increase in the heater's resistance as it warms up. The voltage across the heater is a constant battery voltage from the ECM, so as the heater's resistance rises, the current will drop. https://www.picoauto.com/library/aut...a-with-heater/
The 750 has 2 O2 sensors, so the amps would be double, maybe that ys why they made it different on the 750.

If smoke comes out of the O2 sensor connection on the exhaust, then fix the connection. It is normal for a cold engine and cold exhaust that there is "smoke" coming out.
White Smoke: If you see white smoke, it is most likely a natural occurrence from condensation from cold engine and exhaust. It will disappear when engine and exhaust are at operating temperature and then exhaust is dry

Blue Smoke: Blue exhaust, similarly to gray, indicates that oil is burnt. The first thing you should do is inspect your oil levels. Leaks can be produced by leaky valve seals, broken piston rings, or worn cylinder walls.

Black Smoke: Black exhaust smoke signifies that your engine is burning too much fuel related to an air filter or fuel injector problem.

[Annddrriy]

Do you see technical advantage to shut off the O2 sensor on an M70 engine when engine is hot and cat is hot then ECU shut OFF the oxygen sensor heater no more need it when catalitic is hot. Do you hear sometimes in M70 engine fuel pump buzing most likely you do not hear that buzz. In M30 engine fuel pump buzzing sometimes because the heater of the oxygen sensor takes itseft amps for it from fuel pump relay as you mention earlier the pulses of current start with a height of about 1.3 amps and then decline to about 0.5 amps. This is due to the increase in the heater's resistance as it warms up. When the oxygen sensor heater is OFF then automaticaly more current will go to the fuel pump relay to operate fuel pump properly.
Half of the amps quite a bit good amount of current to take from fuel pump then fuel pump run a bit slower than normal. If pump run a bit slower then fuel pressure in injectors fuel rail build up low.
Why should I check fuel pressure with the gauge if I am sure when the oxygen sensor heater wire is disconnected from fuel pump relay then more fuel pressure will be in injectors fuel rail.

[shogun]

M70 has many parts double, so with 2x O2 sensors, the amps for O2 sensor is double compared to M30, maybe that is an advantage to shut off. 750 has as standard a 140A alternator, that is plenty enough for all equipment. My fuel pumps do not buzz, when they buzz, it is a sign of wear, or dirty filters. Your 735 M30 has a 115 or 140A alternator, plenty of Amperes you never can use. With such an alternator your car has excess Amps and it does not matter if the O2 sensors is always heated or not.

The fuel pump always runs at same speed, even if it would run a bit slower, it does not matter, a proper working Bosch fuel pump on your M30 has the following specifications:
The M30 fuel pump is originally Bosch 0 580 464 995 , operating pressure is 3 bar, conveying capacity at 12 V 1.9 liter/minute, conveying capacity against counter pressure 875 ccm/30 seconds, power consumption is 5A
1.9 ltr/min x 60 minutes = 114 liter/minute
The M70 has 2 pumps, so 1 for 6 cylinders, each: Bosch part number is 0 580 112 507 (according to old repair book), operating pressure is 3 bar, conveying capacity at 12 V 1.7 liter/minute = less than the M30 pump, capacity against counter pressure 875 cc/30 seconds, power consumption 5.5A, 1.7 ltr/min x 60 minutes = 102 ltr/hour x 2 pumps = 204 ltr/hr.
That is much, much more than the engine consumes and the injectors need, therefore the fuel pressure regulators send most of the fuel back to the fuel tank via the return line

[Annddrriy]

Alternator output 140 Amps but when the engine is rinning the conssumers took around 110 amps then 28 amps have left at the alternator on big gauge wire around 15mm diameter. Main relay and fuel pump relay has 1.5 to 2 amps only at the wire 2.5mm diameter. I assume the most current takes ignition coil of wiring primary and secondary windings. For an exapmle If to connect 2.5mm diameter 80cm long wire from alternator to the ignition coil we will have reading 0.5Amps. What amps will be if to connect 5mm diameter wire ?
Will ignition coil charge 0.5 more amps if to make it from 2.5 mm diameter wire to 5 mm diameter wire ?

[Annddrriy]

Has anyone did replace crankshaft main bearings I think engine oil is on torque converter housing dripping slowly. Maybe I am wrong it could be automatic transmission oil not too sure about. Last time checked engine oil level was a bit low then between minimum and maximum and ATF level was also not to bad. Probably the engine crankshaft main bearings wear out and the engine rear main oil seal has oil leak through it slowly but now it has stop oil leak from transmission housing for some reason. Thanks !

[shogun]

you can easily find out which oil that is, engine oil and transmission oil have different colors. Crankshaft main bearing I never had to replace, but the input shaft seal to the transmission has usually to be replaced on every E32 with automatic transmission, that you can see when trans fluid is coming out from the hole of the bell housing/engine http://bmwe32.masscom.net/moswald/zf...umpbushing.jpg

[Annddrriy]

When I checked oil was coming from between transmission bell housing and the engine's flywheel housing where transmission bell housing sticking to the engine rear housing. If is oil has stop leaking that could be transmission oil. If that would be the engine oil it would be still had oil leak. Transmission I bought was seating on the shelf of used parts warehouse for a while. Could be after ride few thousands of kilometers input shaft had fixed the input shaft oil seal ?

[shogun]

Just watch it for a longer time. As I mentioned before, all owners I know with 4HP22/24, we had to replace the trans input shaft seals, I had to replace it on my E32 750 already 15 years ago, it started suddenly and a lot of ATF came out, others had it slow starting and getting more and more leaking.
4HP22, Fixing Leaks https://www.youtube.com/watch?v=m_ppOO5u0NU