Idle stabilisation

[palonte]

Thanks for the advises, but if you read my first post I start quite like you said. Maybe I have to start again in point 0 , because idle valve didn't work propely before I add those diodes (small changes of control didn't act any changes).
Also there are possibilityes to try change "speed density" fueling for some else.

[palonte]

OK now I get excellent log. There was stabil situation going on couple minutes before, then I clear the log and start to record again, after that it took 15 seconds and something happens and engine stops. All other parameters are stable only ignition angle is living.

[cqwanju]

I think this post write very good!

[palonte]

Hi again. Some time has gone after last post. I give car for professional and he adjust all maps in order by using dynamometer. Now there is idle allso running in 950rpm. Ignition angle is living in very wide area and at the same time you can hear that engine is not so stable. So, maybe this engine is not so stabil than some others. Still there is one phenomenon I don't like. When I lift throttle pedal (arrive crossroads) engine running speed goes very low before it's find stabil idle. If the engine temp is high, running speed goes so low that engine stops. Now I have suggestion for program.
There are two parameters in "idle parameters" , afterstart RPM increase and afterstart duration . Would it be possible to add there one parameter more named After throttle duration .
This feature would help my situation and hopefully some other allso. Old Japanese car with carburator had that kind of feature, there was small vacuum "brake" in flap axle and it prevent to engine stop if running speed goes too fast to idle.

[Karel]

What i do for better idle ? Simple

More air , and less ignition angle. Its not the best for fuel economy, gives little higher EGT also, but if you set your idle so that your IGN angle is about 0-5° at wanted revs , it will be stable for sure. The second "trick" is set engine mechanicly so, that it cant go under some idle speed.

So how i do step by step:

Lets say my goal is 900RPM

1) open throttle mechanicly to something like 1500RPM
2) set the IGN timimng to 0° in are 0-2000RPM and load around wanted area
3) set the idle stepper, solenoid or whatever to minimum air position
4) adjust fuel to cca 0,9-0,95lambda
5) set screw on throttle to cca 800RPM
6) adjust fuel to cca 0,9-0,95lambda again
7) set little more IGN angle on lower RPM row (just +3 to +5degree)
8) set the idle strategy (stepper, solenoid or ign control)

In this case, your engine will not be able to fall below 800RPM, so will never die, and you are just 100RPM away from wanted RPM, so there is not so much work for the ecu to raise this 100RPM and hit target.

Small changes in nearby areas, smooth changes in maps are the key for smooth engine handling.

[bmwmaster]

Thanks for the advises, but if you read my first post I start quite like you said. Maybe I have to start again in point 0 , because idle valve didn't work propely before I add those diodes (small changes of control didn't act any changes).
Also there are possibilityes to try change "speed density" fueling for some else.

Hi,

i have the same problem with my 3-wire idle valve. It doesn't respond well in small areas near 50 DC.
Because of that i decided to install flyback diodes. In the old manual it wasn't mentioned to install them with 3 wire idle valves.
In the new manual there is a picture.....but im not sure and need little help how to install them.

Do i understand this sample right ? Can somebody explain how the diodes work in this case and what is the effect ?

[Jadzwin]

Hello!

This is a bug in the software. It is already fixed. The software 1.110 should be available in next 2 days.

[bmwmaster]

Good to know, i hope it will work better. Im fighting with this strange idle valve behavior since some months and always thought that it is because of my settings.

[Jadzwin]

Sorry for the issue
There is new software 1.110 where this bug is fixed

[bmwmaster]

No problem, i already read about the new fuel Model, ist sounds interesting but is not 100 percent clear for me. Can you please make a thread where you explain more. Whats the advantages of it and so on. For me it sounds like we have to set the lambda table complete and when everything is setup and working right, emu is able to directly set fuel amount to reach this.
It is somehow not clear because of volumetric efficiency and so on.

[Jadzwin]

The main advantage is if the car is tuned correctly, you can remove wideband oxygen sensor and then just adjust lambda table to change the mixture. So in advanced model the VE table is "true" engine volumetric efficiency (in basic model the VE table is used to set up Lambda for different Load/RPM"
The Charge temp estimation table (works with basic and advanced model) is nice improvement. It makes low load fuel calculation more precise (eg. more stable Lambda at idle )