M30 engine ECU learning

[Annddrriy]

What voltage should be at the Engine ECU pin 54 when KOEO or Run 0km/h ?

[Annddrriy]

Hello everyone ! Anyone know how relay circuit works with engine ECU ?Thanks in advance for your answer !
Screenshot_20221006-185657.png

[whiskychaser]

The DME grounds pin 85 of the relay causing it to throw and connect pin 30 (permanent live) to pin(s) 87.

[Annddrriy]

Thanks ! Is pin 21 TD/TR signal of transmission get receiving signal from the engine ECU pin 3 fuel pump relay ?

[whiskychaser]

Yes. Pin 3 of the DME can switch to ground and output the TR signal.

[Annddrriy]

When I check on transmission pin 21 TR signal frequency It should be between 35-45 Hertz when the engine running at idle speed RPM 800 If I disconnect wire harness from transmission TCU then TR signal will remain on engine ECU on pin 3 ? Vehicle will EML the engine ECU pin 3 connected directly to the fuel pump relay. The automatic transmission TCM pin 21 not connected to the engine ECU pin 3. The TCM pin 21 is connected to the engine ECU pin 6 which is engine speed.

[whiskychaser]

There is enough capacitance in 6" of wire to knock a circuit off frequency. So unless you have found instructions to the contrary, I would not do that.

If you are concerned about DC in the circuit when you are checking the frequency, connect your frequency counter's + cable to one leg of a small ceramic capacitor and use the other leg as the probe. That will block the DC and enable you to read the AC signal. Bear in mind that you may need to put the black lead on PCB ground, not battery ground. That is not going to be easy with the board inside the case

[Annddrriy]

Frequency between TCU pins 5 and 21 at idle something cause frequency drop to zero. The frequency not stay between 35-45 Hertz it go to zero every 2 seconds. Is engine ECU malfunction properly ?
Thanks in advance for your answer !

[whiskychaser]

Just so we are all on the same page, could you confirm where that frequency band is mentioned in the documenation and what you are using to check it? Is it possible that you are losing signal rather than it dropping out?

[Annddrriy]

I am using 4 channel scope at 100Hz scale. What could cause to loose frequency signal ? It could cause frequency signal to lose that is code 54 which is converter clutch drive position switch is stored in the engine ECU when the TPS pin 5 wire is in place if the TPS pin 5 wire is disconnected then code 54 not stored in the engine ECU. Technical Data TD/RT Signal Engine idling @ 800RPM (pin21 to5 ) Hertz 35-45
Screenshot_20221009-142117.pngfrequency waveform of transmission TD-TR.jpg

[whiskychaser]

Unfortunately, the data does not confirm which modules the pins relate to. It states pin 21 to 5 and we might assume that means TCM pin 21 to DME pin 5. But that does not tally with the wiring diagram. TCM pin 21 actually goes to DME pin 3, not pin 5. You might lose signal because of a poor connection, shielding or faulty component. Are you getting a code which suggests there is an issue with the TR signal?

[Annddrriy]

Technical data frequency check TCM pin 21 and pin 5 on TCM only not on ECM. ECM ground pin3 fuel pump relay connect with TCM pin21. There is issue with the engine misfire. The ignition distributor cap problem could be big gap between the distributor cap and the rotor and need to be wired somehow.

[Annddrriy]

Frequency lost could be bad fuel pump. TCM pin 21 shares the signal with ECM pin 3 which is groung controlled by the engine ECU. If fuel pump is good that is most likely the engine ECM not good.

[Annddrriy]

Anyone knows how the engine ECU adjust fuel mixture when ignition distributors cap not working properly ? It makes fuel mixture lean or reach ?

[shogun]

The ECU does not have any direct feedback from the distributor cap if a distributor cap or rotor has cracks and does not work properly. It get's the signal from the donut = cylinder identification sensor on ignition wire # 6 + other sensors as mentioned below. The ECU gets the signal for crankshaft position from the CPS and the sparks will come accordingly. If the cylinder identification sensor is not working, then the ECU goes in gang fire mode.

Cold start control: at the beginning of the start phase, an increased amount of fuel is injected 3 times per cylinder group up to 5 crankshaft revolutions. This depends on the engine temperature during the start phase.
During the starting phase, the initial injection quantity is reduced depending on temperature and engine speed in order to prevent to much fuel injection. If the engine is started again within 1 minute, the full start injection quantity is no longer injected. After starting from approx. 600 RPM, injection takes place only once per crankshaft revolution per cylinder group. This means that injection takes place into cylinders 2,4,6 at the first revolution and into cylinders 1,3,5 at the second revolution. In the warm-up phase up to 70 degrees Celsius engine temperature, the injection times are also extended depending on speed and temperature; these values are permanently programmed in the control unit.

Semi-sequential injection: From a speed of 600-800 RPM, only 1 x per 720 degrees crank angle is injected into a cylinder group (2-4-6 or 1-3-5). This control can only work if the DME control unit receives a signal from the cylinder identification sensor CIS/ Donut at the ignition wire cylinder 6.

Parallel injection: Parallel injection means simultaneous injection of all injectors per crankshaft revolution and only occurs when the cylinder identification sensor / donut does not provide a signal.

From technical paper Motronic 1.1 and 1.3:
Cylinder Identification (CID) : An cylinder identification sensor is used to identify cylinder firing sequence. The sensor is connected around the HT lead of cylinder number 4 (4 cylinder) or cylinder number 6 (6 cylinder) adjacent to the distributor. As the HT pulses travel along the HT lead, a small AC signal is induced in the sensor and returned to the ECU. The ECU utilizes an ADC to transform the signal into a digital pulse. Fuel injection: The ECU contains a fuel map with an injector opening time for basic conditions of speed and load. Information is then gathered from engine sensors such as the AFS, CAS, CTS, and TS. As a result of this information, the ECU will look-up the correct injector pulse duration right across the engine rpm, load and temperature range. The injectors are arranged in two banks with injectors 1 and 3 (4 cylinder) or 1, 3 and 5 (6 cylinder comprising one bank, and injectors 2 and 4 (4 cylinder) or 2, 4 and 6 (6 cylinder) making up the other bank. Each bank is connected to the ECU via an independent ECU pin. The Motronic 1.1 & 1.3 multi-point injection system pulses the injectors semi-sequentially and once every two engine revolutions. During engine start-up below 600 rpm the ECU pulses all injectors simultaneously. Once 600 rpm has been attained and if the ECU has received a signal from the CID sensor, each injector bank will be pulsed alternatively according to which pair of cylinders are approaching TDC. If a signal is not received from the CID sensor the injectors will remain on simultaneous operation. However, if the CID sensor subsequently sends a signal to the ECU after the engine has commenced running, the ECU will pulse the injectors semi-sequentially after the next deceleration phase - even if the CID sensor then ceases to send a signal. During start-up from cold, injector pulse duration is increased to provide a richer air/fuel mixture and pulse frequency is also increased. In addition, the ignition timing is also retarded. Injector frequency & pulse duration and degree of timing retard depend upon the engine temperature both during start-up and immediately afterwards. If the engine is restarted within one minute of the first start occurance, less overall fuel is injected to reduce the risk of fuel flooding into the engine. Fuel injectors: The fuel injector is a magnetically operated solenoid valve that is actuated by the ECU. Voltage to the injectors is applied from the main relay and the earth path is completed by the ECU for a period of time (called pulse duration) of between 1.5 and 10 milliseconds. The pulse duration is very much dependent upon engine temperature, load, speed and operating conditions. When the magnetic solenoid closes, a back EMF voltage of up to 60 volts is initiated. The fuel injectors are mounted in the inlet stubs to the engine inlet valves so that a finely atomized fuel spray is directed onto the back of each valve. Since the injectors are pulsed in two banks, fuel will briefly rest upon the back of a valve before being drawn into a cylinder.

Also the fuel pump relays have been changed over the years. The oldest ones had orange color 61311378301, then came blue and now light green. The new fuel pump relays are light green or blue and do not switch off at low voltage like the orange ones, but the pump relay is switched on by the main relay! The green has 2x terminal 87. BMW Multi Purpose Relay; 5 Prong; Light Green 61368373700, 5 Prong; Light Green, This relay may also replace original 4 Prong relay. Cross References: 12631714976 12631735424 54347025596 61311350315 61311373585 61311378297 61311378301 61311459577 61319057005 61360153636 61361378238 61368366600 https://www.wpdusa.com/products/2796...506005001.aspx

[Annddrriy]

I mean when ignition distributors cap not working properly it gives low spike kv on some of the cylinders. What will happen if on the identification cylinder #6 wire low kv then cam sensor can not send a signal to the engine ECU and then the engine goes into gang firing and over fueling intake manifold by injectors. Live data shows lean/reach it stay between lean and reach. Fuel consumption shows on board computer L100:17.1 Which over fueling.

[Annddrriy]

Do you know how many AC volts send cylinder identification sensor to the engine ECU ? Thanks !

[shogun]

Here you have the Motronic diagram of the M1.3 https://www.e34.de/tips_tricks/motronic/m1_3.pdf
The injection time depends under normal condition on many factors as described above, such as cold start, engine temperature, air temperature etc
In case the spark is to weak that the donut = CID cannot measure it, the DME switches to Parallel injection: Parallel injection means simultaneous injection of all injectors per crankshaft revolution and only occurs when the cylinder identification sensor / donut does not provide a signal. The pulse duration is very much dependent upon engine temperature, load, speed and operating conditions.

Comment Bill R.: If the inductive sensor on the plug wire fails then it goes into gang firing, since the m30 is a semi sequential design meaning that it triggers the injectors in 2 banks of 3 every other revolution, when it goes into gang fire, it triggers all six at the same time every revolution but decreases the volume of fuel by 50%. And i would imagine that all six triggering at the same time would make a much louder noise...


ECU (DME) sensors run off 5v is mentioned here https://www.bimmerforums.com/forum/s...CU-DME-hacking

[Annddrriy]

As I understood you posted before about the cylinder identification sensor transform small AC volts onto digital pulse to the engine ECU where #6th cylinder is to let injectors know what time to spray fuel. IF donut not working then the engine ECU takes signal from air flow meter sensor and coolant temperature sensor and bypass donut. With two digital multimeter each of them connected to the engine ECU injectors pin 16 and 17 can we tell the donut not provide a signal to the engine ECU if two digital multimeter shows at least 30 volts when engine is running ?

[shogun]

The DME has a self diagnosis system. If donut/CID is not working: parallel injection, see above. In case of failure / unplausible data from temperature feeler coolant temperature sensor, air MAF sensor, air volume sensor, O2 sensor do not work = the DME uses a programmed default value. If the sensor signal comes back normal, the DME again takes such value.
DME voltage/power supply to DME: < 10V. If the voltage to the DME exceeds 16V, you get a fault code. If below 10V : fault code after engine has run for 3 minutes.
Donut/CID: 0.2 - 1 ohm, at 23 +/- 5 degree Celsius.

ECU bypass donut probably no one has ever tried, because we all want to have a working donut which is needed to know when injections have to be made.

Here you have all the data and explanations in German language, translate it, DME 1.1 and 1.3, 27 pages Pruefanleitung Fahrzeugelektrik/-elektronik Test instructions electrics/electronics for M20 and M30 https://web.archive.org/web/20141031...DME11-735i.pdf

[Annddrriy]

Donut connected or disconnected and the engine remain run same. Donut not work with ECU. If donut not working with the engine ECU you should see the 1444 code when you do stomp test the engine ECU has internal electronic ground short.

[shogun]

Cold engine? Warm engine? Directly after start?
Cold start control: at the beginning of the start phase, an increased amount of fuel is injected 3 times per cylinder group up to 5 crankshaft revolutions. This depends on the engine temperature during the start phase.
During the starting phase, the initial injection quantity is reduced depending on temperature and engine speed in order to prevent to much fuel injection. If the engine is started again within 1 minute, the full start injection quantity is no longer injected. After starting from approx. 600 RPM, injection takes place only once per crankshaft revolution per cylinder group. This means that injection takes place into cylinders 2,4,6 at the first revolution and into cylinders 1,3,5 at the second revolution. In the warm-up phase up to 70 degrees Celsius engine temperature, the injection times are also extended depending on speed and temperature; these values are permanently programmed in the control unit.

Semi-sequential injection: From a speed of 600-800 RPM, only 1 x per 720 degrees crank angle is injected into a cylinder group (2-4-6 or 1-3-5). This control can only work if the DME control unit receives a signal from the cylinder identification sensor CIS/ Donut at the ignition wire cylinder 6.

Parallel injection: Parallel injection means simultaneous injection of all injectors per crankshaft revolution and only occurs when the cylinder identification sensor / donut does not provide a signal.

In case there is no difference between connected donut and disconnected donut, then the donut is defective. Make another test with disconnected and connected donut and touch the fuel injectors by hand, there should be a difference in injections.

http://www.944online.com/yabbfiles/A...tronic-1_3.pdf
Cylinder IdentificationIdentification (CID)
An cylinder identification sensor is used to identify cylinder firing sequence. The sensor is connected around the HT lead of cylinder number 4 (4 cylinder) or cylinder number 6 (6 cylinder) adjacent to the distributor. As the HT pulses travel along the HT lead, a small AC signal is induced in the sensor and returned to the ECU. The ECU utilises an ADC to transform the signal into a digital pulse

[Annddrriy]

Tomorrow I will check if all 6 injectors runs at the same time if donut not working or disconnected. If donut disconnected all 6 injectors should be powered at least 30 volts on ECU pins 16 and 17 when engine is running. If donut working ECU pin 16 and 17 should work ON/OFF at least 60 volts.

[shogun]

Limited Operating 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. This procedure is often termed limp home. A serious fault occurs when the signal from the sensor is outside of its normal operating parameters. When operating in LOS the engine may actually run quite well with failure of one or more minor sensors. Since the substituted values are those of a hot engine, cold
starting and running during the warm-up period may be less than satisfactory. Also, failure of a major sensor, ie the AFS, will tend to make driving conditions less easy. Once the fault has cleared, Motronic will once more accept the live signal from the sensor. The following LOS measures are taken in the event of a failure
Component......Action
AFS .................substitute values are calculated from the TS position. The load signal is fixed to 6.0 ms and the ignition timing to 20°BTDC once the TS contact is open.
ATS.............substitute value of 50°C . A code will not be set, and LOS will not commence until a minimum of 3 minutes after engine start and the engine idling for a minimum of 30 seconds.
CID/donut...injectors are pulsed simultaneously
CTS...substitute value of 2.77 volts. CTS substitute value of 80°C if ATS value is greater than 20°. if ATS value is less than 20°, substitute value of ATS value for first three minutes after engine start-up .
OS..... substitute value, open loop control
TS..... substitute values, restricted engine operation

Cylinder Identification (CID)
An cylinder identification sensor is used to identify cylinder firing sequence. The sensor is connected around the HT lead of cylinder number 4 (4 cylinder) or cylinder number 6 (6 cylinder) adjacent to the distributor. As the HT pulses travel along the HT lead, a small AC signal is induced in the sensor and returned to the ECU. The ECU utilises an ADC to transform the signal into a digital pulse.

Pin..Item..............condition..............volt s/frequency/duty cycle
8...CID signal....t2 engine running .....less than 1 ohm
31..CID return... t1 engine running....0.25 max
more here http://www.944online.com/yabbfiles/A...tronic-1_3.pdf

[Annddrriy]

Checked Donut CID: 0.2 - 1 ohm, at 23 +/- 5 degree Celsius. Checked ECU pins 16 and 17 when the engine was running both pins gets 13.5 volts. The engine ECU not even give 20 volts to the injectors. The DME switches to parallel injection. Parallel injection simultaneous injection of all injectors per crankshaft revolution. Injectors is not turning off. The problem is in the engine ECU if is ignition distributors cap not makes proper secondary ignition KV for donut if donut needs at idle for an axample 15 kv it will gives engine ECU 5 volts and if is 10 kv at idle then donut gives 4.75 volts or less.