With this entry, I start a new series of articles regarding the management and diagnostics of the B58 petrol engines. There will be information regarding ISTA DME call-up function possibilities and the Expert mode “for a desert”.
I will skip descriptions regarding the crankshaft and/nuances of connecting rod bearing shells (BMW engineers have had the fight to solve it), and other mechanical things – each of you can read in ”Technical training. Product information. B58 engine”.
The B58 management system is provided by DME 8.6.0. Bosch has taken over the relay race; the management module is similar to B48 and N63TU2.
In the beginning – simple introduction info regarding several nuances of B58. And on first hand – regarding emission control system, used by B58.
B58 uses two Lambda probes to control the exhaust gasses. Everything is maximally simplified.
Before the CO catalytic converter, Bosch LSU ADV wide-band probe is placed, after CO catalytic converter – a “simple” narrow-band Lambda probe.
More about differences of LSU ADV from LSU 4.9 (Lambda probe of the previous generation) you can read here, but in short:
a. calibration resister is not placed in the plug anymore, but the sensor element of the probe itself is calibrated at the factory. Accordingly, the 6th contact in the plug is not necessary anymore (now the plug has only 5 connections);
b. the curve of the probe depends on the pressure in the exhaust, but, as the engine works only in Homogeneous (more precisely – Lambda around 1.0) mode, it does not cause problems;
c. the “Light off” time of the probe is shorter (it is essential when using Start/Stop system), and it can work in higher temperatures – it is necessary for the turbocharged engine.
Of course, there is no exact information of the manufacturer, but it looks that for these engines, the fuel mixture in idle is maintained a bit leaned than previously. The voltage of the control probe is maintained not around 0.75V as once but is even below the middle point of the active area of the probe, and the target value is 0.25V. Such a solution means Lambda is slightly above 1.00 (with a minimal amount of air leftover). Small leftover of the air means – the CO catalytic converter can perfectly burn the small amount of partly burned or completely unburned fuel. A slightly leaner fuel mixture reduces the content of CO/HC in the exhaust. It, in turn, is important when we talk regarding strict rules of EURO 6 exhaust limits. Such a solution is possible because, in the new engines, the performance of the CO catalytic converters is measured on the go and differently than “previously” (in the era of the narrow-band probes). Regulation range of Lambda: +/-0.02. In the mode of the average load, everything is like in “old times”: target voltage is 0.75V.
Otherwise, the management of the probes does not differ from the previously seen. The probes are warmed with PWM (maps of the adaptive warming-up). Periodically the inside resistance of the probes is measured, and it serves as a temperature standard and is used to adapt the PWM warm-up maps.
It’s funny that in the description of the B58 engine performance, you can find this:
This principle of performance is actual for the “pre-historical” Bosch LSU 4.2 wideband Lambda probes. Already since LSU 4.9 sensors, the ambient air is not supplied to the probes! That is exactly one of the fundamental upgrades (and newer – also LSU ADV) of these probes.
According to the information of the manufacturer regarding these engines (info is widely available on the Internet), the new Valvetronic:
a. has become more compact;
b. minimal valve opening is reduced till 0.2mm;
c. an impressive reaction time has been achieved: the eccentric shaft takes only 0.3 seconds to turn from min to max. Impressive!
From technological upgrades, the forced oil of the unit “Valvetronic motor/eccentric shaft” is particularly noted. Also – when the motor needs to be replaced, a specific tool should be used, and a learning procedure should be observed very carefully. Both procedures are more important than previously. Why?
Here, the Valvetronic connection. As we see:
a. motor – servo (BMW has made conclusions from problems with the DC motors of the first generation), I’m glad about it;
b. position sensor – not mounted on the eccentric shaft, but – on the servo motor itself!
That’s why mechanical regulation is necessary if the servo motor is replaced! Free movement is not accepted in this hub – DME will not see them (and, accordingly, will not compensate)!
And also, a learning procedure has completely other meaning – after replacement of the servo motor, DME has no slightest illusion regarding the position of the eccentric shaft!
The benefit of this solution is clear – the engine is maximally simplified. Also, in case of any errors, no one has to guess where exactly the problem is – in motor or sensor. A hub should be replaced! Exactly the same principle is used in the new VANOS. The VANOS valve is merged in one hub with the sensor.
Heat management module
B58 doesn’t have classical heat management. The thermostat is replaced with a Heat management module. This is the electrically manageable valve, which is named very glamorous. The fact that the DC motor is used for a drive made me careful.
Yes, as we see – a regular DC motor. I understand that the expected number of the work cycles is low (obviously, the simulations and tests of BMW confirm the motor’s longevity), but – DC motor in such a responsible hub… Would really servomotor cost significantly more?
Cooling of the turbocompressors
A separate additional cooling motor is used; BMW says it can work even for 30 min even after shutting down the engine. But, here also: DC motor! Impressive.
In their materials, BMW mentions that “low power” mode activation is also possible for this motor. TIS, instead, mentions that in DME, the error messages regarding this motor are intended. Data communication type is not specified (in info materials, it’s called “activation signal”), but hopefully (previously mentions regarding change of the modes and the problem recording in the DME suggests that), that the communication is two-way and allows correctly identify problems of the system. And there are many potential problems:
b. dry run (the motor runs “on dry”, there is no liquid or it’s in gas condition);
c. defect of the motor (for example, increased rubbing, the defect of some rotor winding);
d. complete motor failure.
The good news: BMW has serious experience with the use of the DC motors in fuel pumps (and in their EKP management modules), hopefully, that there will be no surprises (as with, for example, the first generation of N63 engines, in the cooling hub of the turbocompressors).
And, what is not less important – no more complications in the filling of the colling system. No more high-temperature thermostat, which would cause problems. No more need for a specific tool. True though, the filling procedure, using dealer’s diagnostics tools, no one has canceled.
The oil pump and water pump
The oil pump with an electrically manageable bypass valve and “analog” oil pressure sensor – the pump itself is upgraded. Still, the principle of the performance of the pump is similar to in previous N series engines. Oil pressure in the emergency mode has been increased, and now it is 11.4 +/-1.4 bar. Impressive!
The water pump (again, as in old times) has become mechanical. Interestingly, it is identical to the water pump used for B48 (the small, 4-cylinder version). I hope that B48 is used the pump, engineered for B58, not vice versa – pump of the weaker version (B48) adapted to B58.
Two manageable DC pumps help to mechanical (the main) water pump: one of them cools the turbocharger (mentioned previously), other – installed in the low-temperature contour.
Have to admit that the number of pipes and their connectors is impressive:
I assume that the leakages of the cooling system will be one of the annoying problems of this engine.
In their descriptions BMW mentions, that the same asymmetric “beam” injectors, which were introduced a while ago after the upgrade of the N20 engine (to let the engine fit in the EURO 6 exhaust gas norms), are also used in B58. More about this you can read here. In promo materials, everything looks nice, but in life, the situation is “slightly” more complicated. This is interesting as an example. For the F32 LCI encoding of injectors is not intended. That could mean that Delay (actually, this parameter is indicated on the body of the “new” injectors) scattering is small – the injectors are precise. Hopefully, it also is/will be. The most unpleasant conditions:
a. the injectors are screwed directly in the Rail – to replace one injector, all Rail (or at least – half of it) has to be dismantled:
To fulfill the demounting/mounting jobs as intended by the manufacturer, at least 8 (!) different special tools (5 sets) are necessary! Every time following things should be replaced: the bolts with which the Rail is fixed; the bolts with which the injectors are fixed; the Teflon rings of the injectors. I assume that many alternative services (and even dealer services, taking into account a wide scattering of their worker’s qualifications) will “have fun” with the replacement of the injectors.
It was quite funny to read TIS, in which the warning regarding damage, injury, and other troubles during the injector replacement procedure was mentioned 33 (!!!) times!
b. second unpleasant thing: in ISTA, no information regarding adaptations of the injectors is available! Note: with adaptations, I don’t mean the exact value of each injector, but multidimensional adaptation maps, which are created for these (actually – with complicated injector management) engines. It means – even if there will be any uneven performance; permanent vibration; increased detonation in some cylinders will have to do with indirect confirmations of the defect. At least till the moment, till the injector adaptation data don’t “drop” outside the allowed norms. Norms typically (how the experience with MSD80 and DME’s of other N series engine shows) are very wide – a certain “fun” can be expected at this aspect.
B58 is not quite “my” engine. I love advanced technologies, complicated solutions. B58 is a “workhorse” – simple, rough. The good news – it looks that it will don’t cause many problems to their owners. At least in a range of reasonable mileage. Of course, nothing is eternal, and after a long or very long time, everything, what can break down – turbocharger; DC motors; all possible mechanical parts. For sure, there will be HVA (and due to these – as if Valvetronic, which gives vibration in idle; increased load of the CO catalytic converters; etc.) and VANOS valve problems due to rare oil changes (typically, manufacturer’s specified oil change interval in EU is 30’000km). But the user experience of the first years shows that these engines have no such severely weak points. And that is only logical – the engine actually has no new, untested solutions. The complete unknown is the injector part – the time will show the true situation.