BMW 530d EDC15C35 EGR off and hot start fuel map adjusted to cold conditions needed

[gago]

Hi,
If anybody can please turn EGR off and adjust the hot start fuel injection quantity to match the cold start or close to.
It's hard starting when hot, at 90degC coolant it injects ~20mg/st, while cold, below 20degC or so it injects ~40mg/st and the starting characteristic is perfect. Engine speed during cranking is about the same cold/hot at ~170rpm.
Thank you.

p.s. it's EDC16c35

[NASTASE]

Here mate.

[gago]

Thanks mate, tested and working, EGR is off (duty cycle at 5%) and 32mg/st at 75degC coolant for start (much better, doesn't stumble anymore).

[gago]

After a longer trip this evening (motorway) I've noticed an odd behaviour in that the dpf was at regen mass at+40g only that the combustion mode did not switch completley to regen, from time to time it was actuating in mode 4 for a few secs then back to 0 and so on (dpf in temp was rising during those actuation but never reached what was supposed to and the soot mass went down by a bit every time). In the process the car was sligtly jolting when the comb mode was changing, something I've never experienced before at motorway speeds

No issues with the dpf, dtc, etc, before. Same for the egr.

Is there a possibility that some of the dpf variables/maps were affected in the process of disabling the egr or do I need to reset the dpf time after flashing the calibration or there is something else?

Thanks.

[bobolin4o]

What was the intention of disabling EGR initially?

[NASTASE]

After a longer trip this evening (motorway) I've noticed an odd behaviour in that the dpf was at regen mass at+40g only that the combustion mode did not switch completley to regen, from time to time it was actuating in mode 4 for a few secs then back to 0 and so on (dpf in temp was rising during those actuation but never reached what was supposed to and the soot mass went down by a bit every time). In the process the car was sligtly jolting when the comb mode was changing, something I've never experienced before at motorway speeds

No issues with the dpf, dtc, etc, before. Same for the egr.

Is there a possibility that some of the dpf variables/maps were affected in the process of disabling the egr or do I need to reset the dpf time after flashing the calibration or there is something else?

Thanks.
I'll send you a new file, with hot start fix and only hysterezis maps moded for EGR off.In my first version is EGR removed.

[gago]

Hi, the intention was to prolong the DPF life and limit the wear for the intake manifold, valves, cylinder liners due to additional soot being induced.
Most of my drive is city >80%, so I'm not to concerned about NOx as the load is low, but I would like to keep the DPF given the effects of soot for our health.

[gago]

I'll send you a new file, with hot start fix and only hysterezis maps moded for EGR off.In my first version is EGR removed.
Thanks, I'll give it a try this afternoon and report back.

[gago]

All seems good now, it did a full DPF regeneration once the engine warmed up and no more intermittent pre activation. EGR is off at 5% duty and there are no DTCs.
Hot starts still seems to be taking a bit longer than expected especially at high coolant temp >80degC (I need to record some at various coolant temps to check the profiles) but at least is not cronky.

[NASTASE]

All seems good now, it did a full DPF regeneration once the engine warmed up and no more intermittent pre activation. EGR is off at 5% duty and there are no DTCs.
Hot starts still seems to be taking a bit longer than expected especially at high coolant temp >80degC (I need to record some at various coolant temps to check the profiles) but at least is not cronky.

Try this new file, I added more fuel on crancking, but anyway I guess your high pressure fuel pimp is close to end.

[gago]

Thanks for the last calibration file.
The high pressure fuel pump builds up pressure nicely, ~70bar after 0.3s in both cold and hot conditions, in hot conditions when it takes longer it builds up to 175bar, anything more that 30bar should be enough to fire.
I guess you're referring to the fact that with so much fuel added the pump might not be able to deliver or the injector will become the limit factor in terms of injection time?
Initially I taught that I might have a leaky injector but that also doesn't seem to be case, the idle corrections are less than 0.2mg/st and the rail pressure not being an issue I can't blame them.
The other thing might be the slow cranking speed (~170rpm), I know that the starer motor was replaced a while ago before I bought the car, I checked the ground point between the engine and the chassis and is seems fine, I might add a new ground strap on top of the current one (battery is brand new, Exide 95Ah, 850CCA AGM).

Example with the original calibration before any extra fuel was added (black lines are for cold start at 3degC, and black for hot start at 65 or 75degC coolant temp):
687400

[gago]

On another note, does anybody have any idea what are the differences between 530d LCI and 730d, exact same engine, probably slightly different exhaust and pre air filter air path only that the 730d has 520Nm vs 500Nm max for 530d?
I don't have any info about the 730d in terms of calibration, sw, hw numbers..

[NASTASE]

Your engine need min. 200bar on rail to start. Untere Stellwertbegrenzung des Raildruckreglers über Druckregelventil während der Startphase value is 200bar.

[gago]

Hi, that would be the limit (maximum) value not necessarly the expected set point (risk of bore wash, very high wear levels during start). The pump will be on full flow until that value is attained only that no pump is that efficient especially at low speeds, during cranking in our case.
In other words anything higher than the compression pressure + a few tens (at least 10bar to compensate for any loses) of bar above will be able to inject in the piston bowl and the engine should start.

[NASTASE]

Untere Stellwertbegrenzung des Raildruckreglers=Lower control value limitation of the rail pressure regulator

[gago]

Untere Stellwertbegrenzung des Raildruckreglers=Lower control value limitation of the rail pressure regulator
I won't pursue this mostly because I appreciate your help provided so far and I'm quite happy with the results (I haven't tried yet the last cal).
My HP pump's duty cycle is ~25-30% even at 1600 bar full load, I don't have any reasons to believe the pump is dying. Pre set for start is ~45% and it drops during the start sequence down to 30% with the pressure build up.
It's an easy check if you want to verify the strategy by disconnecting the injectors, crank for 5-10s and see what the rail pressure does when it achieves 200bar it it's being allowed to increase or will be limited. Still the 200bar's got nothing to do with the minimum required to actually start the engine.
Let just agree that we disagree :D.:dancing:

[NASTASE]

On last 15 years i logged a lot of common rail engine at start to look for rail pressure, most of them because of bad hot start.None started under 170bar,some of them not under 200bar.ECU it will not open the injectors under a preset pressure.An used pump can achieve the start pressure at cold because the diesel density is higher but on hot engine ,due to the low diesel density, the start pressure is harder to reach.Just my opinion.

[gago]

Well, clearly this one starts at a pressure much lower that 170bar, see the previous attached screen shot. It doesn't really matter that the fuel is at 3degC or 65-75degC, the pressure build up is pretty much the same, although the fuel rate request is much lower for hot start, you might be right, I'll keep it in mind, I'll let it wear out more before going deeper in the investigation (injector flow rates, pump delivery, etc..), in the mean time I'll try and see why is not cranking faster in the 1'st place.

[gago]

Can the no load speed be limited to something like 2500rpm in neutral/park (it's a sport auto gearbox)?
This is mostly to prevent the goons at MOT checks to rev it to max speed without any good reason for the smoke test.

[gago]

Hi, I'm getting a shadow error 41ED Cyclic Authentication, which I guess is related to the calibration mods being recognized. Can it be masked, disabled?

On anther note, does the ECU needs to be coded after the calibration is uploaded, pretty much the same time (next day) after I've flashed the cal (MPPS 16) I'm getting a voltage issue, which might be unrelated or purely coincidence in that the altrnator under/over charges, with the alternator connector disconnected all seems good (only the communication error) and it charges in default mode at 14.2V. IBS seems ok, no current/voltage fluctuations with the above connector disconnected.
Thanks.