Hello,
i installed VEMS on my audi RS2 and have the following problems now:
1. After crank up the RPM stay for several seconds high and then it starts going from 1000-1500 RPM so as if i the throttle kick and let and then again. After ca. 30 seconds is it away and idles very nice.
2. I cant set the boost control up (i wanted 1 bar but it goes to 1.4)
3. At that 1.4 Bar the Injector flow rate goes to 85% and the ms to 25 and there i get a fuel cut. With the stock Motronic chipped i got 1.7 bar at this area without any issues. Can it be that my Lambda is to low and the injector cant cope with it or should i change something in the settings?
Here is a log during this boost period and my MT file:
http://www.vems.hu/files/Boostlog1.xls
http://www.vems.hu/files/mallon%20kalo.msq
Cheers,
Vasilis
That sounds like an issue with the PID control of the idle control valve. I'd bet that the 1000-1500rpm osciliation is more to do with engine temp than time, can you confirm this - is the car more stable when warm?
Are you using simple boost? or the original type?
If you're getting a PW of 25ms with reasonable lambda then you are hitting the maximum PW and need to consider upping the fuel pressure or chainging the injectors so that the PWs come down to something reasonable, the stock ECU may have been happy to turn the injectors on for periods greater than 25ms.
Personally I'd try and cure point 3 before tackling point 2.
Hi,
the 1000-1500 come only at the first 30 seconds after cranking. When the engine is warm it doesnt last so long as on cold and when warm and i hit 1 time the throttle it stays stable.
Boost system is original.
I tryed and set the boost control so now i dont get Fuel cut because on the Inj PW and noticed that i get the Boost i want (almost) but it is not stable. I set it to 1 bar and i get 1.1 then goes down to 0.85-0.9 then again to 1.1 then again down ect.
I set the boost up like here:
http://www.vems.hu/files/MarcSwanson/nea_s6_post_map_update.msq
Where did you get those PID settings for idle?
Extras->Idle PID Ref table, PWM is worth looking at as that defines the targets for idle, make a note of what temperature the oscillations occur at and see what effect changing the value for that temperature in the table has.
Have you been through the setup instructions that are show in the boost setup screen when you press F1?
Hi,
my idle settings can be found here:
http://www.vems.hu/files/mallon%20kalo.msq
From Marc Swanson i got the boost settings. Did had the chance till now so that somebody can drive and i set ip up.
This is the RPM vs Boost vs TPS log:
3490 167.0 99
3550 173.8 99
3605 181.0 99
3669 188.5 99
3733 197.8 99
3797 206.5 99
3870 214.5 99
3926 201.0 99
3939 188.0 99
4092 192.0 99
4115 202.8 99
4146 212.5 99
4297 212.8 99
4249 196.5 99
4338 184.5 99
4421 185.0 99
4447 197.8 99
4587 211.3 99
4622 204.0 99
4618 189.8 85
4559 162.0 5
Basically the issues that you are having are purely to do with tuning of these sub systems. The idle PID looks a little bit too neat for my liking, and using someone elses setup is okay, if you're happy with their level of tuning, they might not mind a bit of oscilation after startup.
What you might like to try is to turn on every high current electrical item in your car and see how the PID tuning copes with it, I'd bet that there will be some oscillation as the IACV is opened to raise revs in order to counter the load on the engine.
Datalog the experiments and we can look at the oscilations in the RPM, also datalog the boost issue, there are many people who can advise when the data is available.
Hi,
i have logs for everything, here you go:
Here is the start-up
http://www.vems.hu/files/Idle.xls
When i put the clutch sometimes (not always) then it goes very deep in the Rev range; see here:
http://www.vems.hu/files/clutch%20and%20idle%20fall.xls
Here the Boost problems:
http://www.vems.hu/files/boost%20problemq.xls
And here is my MT File:
http://www.vems.hu/files/mallon%20kalo%2027-2.msq
I am thankful for every help! I used this files i found for a start. Your experience cannot replaced for Trial/error.
These issues are typical PID tuning issues, take a look at:
http://en.wikipedia.org/wiki/PID_controller
And see if it, and any of the links, mean anything to you.
Hi,
unfortunately i still have the boost fluctuation problems with both Open loop and closed loop settings.
I didnt have very much time to try it out extensively.
I am also going fot the Diode mod on the Idle stabilisation valve so the idle gets even better (now it is very good but here we can go to perfection i think).
My only concern is the boost N75 problem. If i get it sorted i will start to look at the Knock sensor settings.
Thanks,
Vasilis
Have you seem Mattias's idle valve tuning:
http://www.vems.hu/wiki/index.php?page=MembersPage%2FMattiasSandgren%2FIdleValveTuningGuide
He's on an Audi IIRC
Yes, this one has also specific informations.
http://www.vems.hu/wiki/index.php?page=MembersPage%2FPeterJensen%2FAudiSidle
Today i installed the Diode and set the boost settings mentioned here and on my VEMS wiki page. Warm car startup is very nice and the boost very smooth. Thank you very much for your help. I am very happy with the Results.
The next step would be to set the knock sensing better than i have now.
Thanks again
Anybody knows why now and then i have this problem during idle. It seems that the Idle valve doesnt respond so fast. It gets worse with AC.
Can it be that my Idle valve is faulty? It happens occasionally.
http://www.vems.hu/files/Bad%20idle.xls
This is my file at the moment:
http://www.vems.hu/files/After%20Diode%20and%20Boost.msq
Please comment or suggest changes for EGO, VE-Autotune, Idle ect. Whatever you think is wrong please commentate.
Thanks
Today i made a trip and noticed that my EGT are during crousing and increasin RPM in the 100 KPA area at 750 degrees celcious after the turbo. Do you think that it ok is? Please check the Lambda and Spark table and this log i got and comment. The outside temperature was very low i and i think in the sommer it would be even more.
http://www.vems.hu/files/High%20EGT.xls
EGT at 750 is not particularly high, I dont have the equation at hand but the increase in air temp will increase EGT a little, but not much.
Hey,
i know you missed me that why i came with another question. Since i set up my WB correctly i have at the same time changed to E50 Fuel. I have noticed that the Lambda measure it not that constant like it was. Does it have to do with the better settings so that the WB lambda works much fater or is something wrong with it?
Also the VE Autotune doesnt seem to work so good now.
Any ideas?
Interesting...
So it was giving a clean signal, and then you switched to E50 and it became erratic?
I'd suggest NEVER using VE auto tune - further to this, its being dropped in the new firmware releases.
Try turning the EGO feedback off and map the fuel at idle, use your ears more than relying on the lambda at this stage, when you get a clean idle then check the lambda reading - it should be good and steady.
You're going to have a fair amount of tuning to do with E50 - it has the potential for a wholesome amount of power.
Hi, actually it is not s ostable at some cetain points where the VE setting is not close to the amount of fuel needed for the Lambda i set. When it get closer it is more accurate.
I think i must switch to Gasoline agian to see if it is fuel related or not.
As with most systems like that when the error is large the correction becomes larger, and you get values swinging all over the place...
Rob
What does this Misfire icon on the left downside on MT? Does it measure something, when does it lights up and what tune i take care of in order not to light?
I've never seen it not light. I'm pretty sure that its useless feature ::)
Thanks Rob for always beeing there! You are really a great help to me.
If the idle valve is too slow to effectively control the idle, then using the ignition timing based idle control is a good option. I found this helped a lot.
Idle is most of the times ok. A bit of a problem is it when the aircon is running. Then at some points it goes very low!
So, i noticed that when the EGO COrrection starts from 700 RPM then the when off throttle the idle is going in same periods from 750 to 900 then back to 750-900-750-900 till at some point after 10-15 seconds it stays stable at 830-850 RPM.
When the Ego correction is off it stays stable much faster. It is also faster when i use EGO PID of 10 instead of 30.
What do you think?
Today i used the old - wrong - Lambda sensor settigs i had and the idle is stable. With the correct settings the idle is not stable. Any ideas here? It seems the the lambda reading and correction is too fast for the idle so it cant get stable.
How much do the target lambda and your actual lambda differ?
You can set the min rpm value to something like 1500 and not have the EGO feedback in effect during idle.
Rob
Where can i post an excel file? Dont we need the EGO in the idle region to get nice fuel economy, pass the MOT and work with AC ect without problems?
The recipient goes to ImageShack.us, selects "file exchange" option, enters the code in "Pickup" section and transfer starts.
http://www.imageshack.us/?pickup=80117797192608
Code: 80117797192608
http://www.imageshack.us/?pickup=80117797915779
Code: 80117797915779
Can someone please download it and post it here or where could i post a file?
If the fuelling is tuned correctly then EGO feedback would not be required for emissions testing. If the fueling is spot on though the EGO feedback wouldnt have much to do...
Rob
I tryied to Tuen the idle with EGO and VE -Autotune off and it is relly nice now (when the engine is warm). When the engne is cold i still get this inconsistency.
The other problem now with the idle is the AC. When the AC is on (or many electrical consumers) then when i let the throttle off and turn the wheel the RPM Fall fast and stay not at 820 RPM (where the idle is and the engine Stalls.
Other issue i have is to make the Knock sensing work so i can work with some more boost pressure.
At least now you have a stable idle from which to tune the PID control from.
There is a table with idle temperature settings on one of the screens but as I'm no where near a PC with MegaTune I cant remember exactly which screen it is, but its one of the last options in the idle control section of the Extras menu.