Slow idle

[jimnielsen]

My car idles too slowly.. It really wants to idle at about 700rmp when its warm - too slow. How can I adjust this on a q4?

[wrinx]

Have you checked the Idle Actuator?

I think you need to check the CO levels are correct (adjust with trimmer) and then adjust the accelerator cable screw for the idle.

wrinx

[jimnielsen]

hi wrinx.. well the idle actuator does 'work' - because the car idles with the throttle closed. This is how its supposed to be set up isn't it? The butterfly valve is closed at idle and the actuator valve provides a path for air around the closed throttle. If it could just add a little more air - it would be good! Is it acceptable to simply have the throttle butterfly open a little (with the screw) to increase idle speed? What effect does the c02 trimmer have on idle speed?

cheers, jim ~

[wrinx]

I'm guessing messing with the CO2 trimmer will alter the idle (+/-) at the expense of emissions, which may not bother you :)

The manual just mentions adjusting the idle with the throttle, so I guess having it slightly open is acceptable???

wrinx

[arjunior45]

with the wires on the ICV valve disconnected you must have 700 - 750 rpm at idle.
If not you just unscrew the 'No1 - throttle by-pass screw' till you get the 700 - 750 rpm.
Then you reconnect the ICV and idle must go at 850 - 880 rpm.
ICV gives you an extra 100 rpm {more or less} when connected.

If you can not have 700 - 750 rpm {with ICV disconnected} with the screw No 1, then you must 'adjust' the crew 'No 4 - throttle valve mechanical stop screw'.


ps.
You do know that I hate you for having that low rpm. Mine stays at 1250 rpm with ICV disconnected and I can not find any air leak {so far}.

[jimnielsen]

Thanks Nick / wrinx.. I will do the thing that you have outlined. I not that mt 'adjusting screw' is simply a recessed screw head - it does not have the locknut as pictured in the manual - however it looks to be in the same place.. is yours like my version?

[arjunior45]

yes, the same version and messing with the No4 is not the best choice but it's an acceptable solution.

Did you clean very well the 'by-pass' chanel? This one, when is close / blocked by deposits can give you low rpm and No1 screw non 'working' properly.

[arjunior45]

Did you adjust / register the TPS as it was before?
If you readjust No 4 screw you need to reset TPS.

[jimnielsen]

Thanks for that cut away pic of the throttle body. I have not see it before (what manual is it in??) - but at least I can see now what is actually being adjusted. I have not adjusted #4 - think I'll leave that alone if i need to re-register the TPS..Though I have pulled the whole throttle mechanism apart and reassembled it with out adjusting the TPS either.. hmm..

So.. The aux air actuator valve is only there to "switch in" another 100 rpm when you turn on things such as 'aircon'. that i dont have? maybe I can ditch it?

jim..

[arjunior45]

Thanks for that cut away pic of the throttle body. I have not see it before (what manual is it in??) - but at least I can see now what is actually being adjusted. I have not adjusted #4 - think I'll leave that alone if i need to re-register the TPS..Though I have pulled the whole throttle mechanism apart and reassembled it with out adjusting the TPS either.. hmm..

So.. The aux air actuator valve is only there to "switch in" another 100 rpm when you turn on things such as 'aircon'. that i dont have? maybe I can ditch it?

jim..


The pic is from the manual you can find at the 'tech pages' { http://www.berlinasportivo.org/Technical/q4manual/manual.php }.


The ICV {Air actuator valve} works at idle too {I think gives a 30% more at idle - but not sure}. I do not know how it works with air con on, certanly gives some extra air too.

To register the idle speed in a proper way you must :
1} clean throttle body, screw No1 and 'by-pass' channel of coarse.
2} check WTS {coolant temperature sensor} and replace if necessary
3} register TPS {Throttle position sensor} so that it gives you 0,12 - 0,42 Volt at idle {middle wire of the connector} with ignition key on 'Marcia'.
Having it lower than 0,12 Volt makes the 'ignition warning light' go on - but engine run equally. I have mine at 0,265 Volt.
4} screw the No1 screw to the end.
5} disconnect the ICV {the electrical wires connector}
6} start the engine and warm up the engine up to 92 degrees when the rad fan start to work.
6} wait until the rad fan goes of and then unscrew the No1 until the engine reaches 700 - 750 rpm. Go for the 770 rpm.
If rad fan starts to work while you are registering this screw {No1} stop and wait till the fan goes off and then continue.
Unscrewing this screw more than 1/3 - 1/2 turn it shall start rising the idle speed.

When finished reconnect the ICV and you must have 850 - 880 rpm.

Registering TPS is very easy and all you need is a simple multimeter - nothing more.
If you want I can describe this procedure too.

[SteveNZ]

Thanks for that cut away pic of the throttle body. I have not see it before (what manual is it in??) - but at least I can see now what is actually being adjusted. I have not adjusted #4 - think I'll leave that alone if i need to re-register the TPS..Though I have pulled the whole throttle mechanism apart and reassembled it with out adjusting the TPS either.. hmm..

So.. The aux air actuator valve is only there to "switch in" another 100 rpm when you turn on things such as 'aircon'. that i dont have? maybe I can ditch it?

jim..

Don't touch #4. you need only adjust #1

You could ditch it but then it wont idle up when cold. It wont idle at all when it is cold which is a pain.

Can you adjust the duty to the valve via your emulator?

[jimnielsen]

Steve.. I will give the #4 a go. its possible that the duty cycle of the actuator valve is controlled by the ECU - but there is no information about it in the 'XDF' file that is used as a translation table by the emulator - so you can't adjust it that way anyway..

[arjunior45]

yes you can. The address for the duty cycle is 40-0 to 40-f {in 10105immo map}.

[jimnielsen]

Nick - do you have any info on the format of the values?

jim ~

[arjunior45]

Bite : xx
Conversione : {DecVal x 100} / 255 = %
rpm related

[mpampis_]

does anyone fix that?