Wideband PID settings

[AVP]

Has anyone fiddled around with these much? in my car sometimes it seems that on certain conditions in idle the wideband can keep the mixture stable,and on other it dances around the figure and cannot settle.I know this can be helped with PID settings being more accurate,just wondering is everyone is using the default ones

[gunni]

How irregular is the mixture?

[AVP]

well, on most of the times on idle(which i did my tests on) with 73 VE i got 0.99 to 1.00 lamda which is what i ask of the lamda table to provide to me anyway.That makes idle stable most of the times.

however today as i was in traffic and engine's temp was above 90, the idle was going slowly up and down only a few revs,nothing serious,but i noticed that this is the lamda pid trying to correct to mixture=1.00 when for some reason it is off.

i have had this before as well,so this cannot be fixed with changing the VE table again.It is merely the EGO that should be able to keep the mixture constant with the least amount of oscillation.

then i changed the PID to 65/18/30 today and it seemed to be more stable than before.

that is why i asked whether anyone has tried different pid settings in general

[rob@vems.co.uk]

Do not change the PID settings these are for control of the sensor's heater and nernst cell.
If you want to change the feedback effect then its a case of adjusting Settings->EGO (lambda) Control

You will get premature sensor failure and incorrect readings unless you use the values specified here:
http://195.159.109.134/vemsuk/forum/index.php/topic,55.0.html

[AVP]

Hi Rob, thanks

i thought that the input for wideband reading accuracy was the wideband calibration constant.

Also the ECU was sent to me with slightly different settings than those found on here,and Marc who i asked him said that he got those settings directly from Marcell. Now the differences are in the warm up settings,pump integral limit(255 instead of 132).

on warm up settings i have:
warm up ramp:808.4
abs limit:224
max time spent on abs limit: 62.9
fallback v: 112
retry:24

i havent heard anything from marc to change those settings back to what is shown on the vems website...

[rob@vems.co.uk]

Well if it comes from Marcell then its fact, its irritating that they can't decide on a fixed setting - then finding a way of letting people know...
Can you update that thread with your new warm-up values?

Cheers

Rob

[AVP]

Sure will, i will only do that as soon as we get a confirmation from Marcel, so that we are ok with it.

as far as the PID controller is concerned, all i have tampered with so far is the P of the heater.With a small adjustment i have managed to reduce the oscillation i get on some occasions.I ll keep you posted if anything happens.

my new settings are: Heater P:63 (instead of 70). It appears that on all PID systems, the higher the P, the faster the responce,but the more likely it is that it may oscillate around the desired value.