Author Topic: Stock BMW E30 M20B25  (Read 12666 times)

Offline DMS

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Stock BMW E30 M20B25
« on: March 11, 2011, 08:26:19 am »
I'd like to run VEMS on this machine:



What the car looks like now:



Everything is about stock so it's not that much of a inspiring car. Perhaps it will be in time....

Offline DMS

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Re: Stock BMW E30 M20B25
« Reply #1 on: March 11, 2011, 08:28:16 am »
Can someone take a look on my config: http://www.vems.hu/files/DMS/v3.2_n000355-A-2011.03.11-09.49.47.vemscfg

and a datalog of today's cold start/warmup: http://www.vems.hu/files/DMS/v3.2_n000355-2011.03.11-08.50.23.vemslog

It's running way to rich in my opinion eventhough lambda target is much higher.
« Last Edit: March 11, 2011, 09:06:23 am by DMS »

Offline gunni

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Re: Stock BMW E30 M20B25
« Reply #2 on: March 11, 2011, 10:37:03 am »
The program complains about the Nernst target being out of bounds, what does your calibration documents say?

Also lower your max rpm and map that you allow your closed loop control to operate at, you don´t want it to be pulling out to
much fuel at higher rpms and loads. Something like 4000rpm and 75kpa should be a good safe starting point. Also raise the coolant temp to something higher like 60C° . The ecu is not calibrated to know what kind of lambda to expect below normal running temperatures.

Overall, I would have reccomended Mattias´s config to start of with and then just tune it for  your setup.

Have you verified your ignition timing? It looks kinda high for a M20 at around idle.

Are you using the idle control valve?

Also your Anytrim control is on and effecting the lambda target. Be sure to disable that.

Offline DMS

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Re: Stock BMW E30 M20B25
« Reply #3 on: March 11, 2011, 11:30:14 am »
Thanks Gunni!

Let me first say this is the first time I'm mapping an engine so it's all very new to me. Secondly: it's amazing how much you guys see while I've spend so many hours already scrolling through the menu's. :)

My config is strongly based on Mattias' config.

My lambda settings should be spot on. I've calibrated it with the autocal tool. I'll try again because I find the value strange aswell. (however the sensor won't come loose anymore... It's there for about 5 years already)

Ignition timing is verified. It was the first thing I did with cranking ignition advance set to zero. During cranking it was spot on. When running idle it's running of the ignition map I assume? (This map is directly copied from Mattias' map.)

I'm using the idle control valve. But I understand why you ask this because it's not running idle at 850 rpm like it should be!

Anytrim is now disabled, overlooked that one!
« Last Edit: March 11, 2011, 11:35:38 am by DMS »

Offline mattias

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Re: Stock BMW E30 M20B25
« Reply #4 on: March 11, 2011, 01:12:55 pm »
Double-check your ECU calibration for the battery voltage, it looks kind of high at the moment, it's not normal to have 14.9 Volts.

The cold start is running a bit rich. Given that I don't know how it runs fully warmed up it's hard to say anything about that, the log ends before that happens.
You could simply have a too high req-fuel, bringing that down 5-10% could be all you need but this is normally not done - go by the correct calculation for this number!
Or the VE table should be lowered the same amount.
On the other hand, the warmup enrichment curve has more enrichment than the one from the link in my signature, are you sure you're really using my config?
Drag'n'drop my .vemscfg over the dialogs to which you would like values copied, start with the warmup curve.

About your idle. The IAC dutycycle is much lower to maintain idle rpm compared to what I got, my minimum limit is actually above your normal duty cycle. That means you're either using a different valve or you have an intake leak after the throttle, or the throttle blade is open at idle, it should be fully closed and the valve controls idle.  Begin by disabling all of the idle control, set the integral decrease/increase in the PID dialog to 0, that prevents the valve to move away from the duty cycle dictated by the reference curve, and also disable the ignition based idle control. Now bring up the gauges for IAC target, duty cycle and integral and tune a proper reference curve - I usually make it so that the ref curve creates an idle  200-300 rpm above the target rpm, then I let the "integral decrease" lower the idle to target (enable PID later by setting values for int dec/inc).

Tip: press "ctrl+1" to get to the view I use most of the time.
« Last Edit: March 11, 2011, 02:48:08 pm by mattias »

Offline DMS

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Re: Stock BMW E30 M20B25
« Reply #5 on: March 11, 2011, 06:04:51 pm »
Yes I'm using your config, but I lowered the req_fuel value and it had trouble during afterstart. So I increased the warmup enrichment and it runs much better.

I've been playing around a bit more this afternoon but some strange things appeared which I have to look into. I've made quite some logfiles which I'll use to diagnose.

I switched to another WBO2 sensor and the value is even higher: 192. I've calibrated it in free air.

Anyway I won't react a few days now since I'm about to leave on a snowboarding trip. If I've internet there I'll upload my new config, logfiles and post my findings and additional question.

Again thanks, Mattias and Gunni!

Offline DevInAz

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Re: Stock BMW E30 M20B25
« Reply #6 on: March 12, 2011, 12:11:29 am »
I love reading about e30's keep up the great work! Mattias and Gunni are always big helps!

Devin

Offline DMS

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Re: Stock BMW E30 M20B25
« Reply #7 on: March 16, 2011, 09:27:01 am »
Thanks Devin!

I've checked the logs I made and it seems like lambda is to low because req_fuel is to high. EGO correction is at 85% which is it's maximum value.

Gamma correction is there aswell but I'll have to search to understand this.

Some log files:
http://www.vems.hu/files/DMS/v3.2_n000355-2011.03.11-19.03.08_cold%20start_req20.0.vemslog
http://www.vems.hu/files/DMS/v3.2_n000355-2011.03.11-19.08.18_hot_idle.vemslog
http://www.vems.hu/files/DMS/v3.2_n000355-2011.03.11-19.24.56_60thr.vemslog

hopefully I've uploaded something you guys can work with.

Cheers,
Jan

Offline mattias

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Re: Stock BMW E30 M20B25
« Reply #8 on: March 16, 2011, 11:04:57 am »
Under ECU calibrations, your nernst target is still too high. This is the calibration for the ECU end of the hardware - the one that controls the wideband sensor, it is NOT the wideband sensor calibration we're talking about. Instead of 140 it should be maybe 135. I don't think this is very important, the other value is more important "pump zero pw" makes a distinct difference just one step off the correct value.
You should find your real calibration values, if you lost them and didn't build the board yourself you can email info @ vems.hu your ECU serial nr and ask for your calibration data.
The config sanity check complains, but as the ECU is pretty old the battery calibration is probably still correct, it could be up to component differences.

Under injector settings, you should zero out the injector open time and rampup values, they both contribute 0.2 ms each to the injector open time (see calc model, press  Shift+5) which can make all the difference for the idle lambda. Also put 500 into the injector voltage compensation.
Overall the req-fuel is probably too high, I don't remember but the stock injectors are what, 150 cc/min?  -> 18 ms.

Gamma correction is just a number calculated from all enrichments, don't bother understanding it.
You can check out the calc model gauge group (View menu or press Shift+5) to check out the calculations behind it.