Audi RS2

[billman]

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

[rob@vems.co.uk]

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.

[billman]

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

[rob@vems.co.uk]

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?

[billman]

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

[rob@vems.co.uk]

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.

[billman]

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.

[rob@vems.co.uk]

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.

[billman]

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

[rob@vems.co.uk]

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

[billman]

Yes, this one has also specific informations.

http://www.vems.hu/wiki/index.php?page=MembersPage%2FPeterJensen%2FAudiSidle

[billman]

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

[billman]

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

[billman]

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

[rob@vems.co.uk]

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.