Idle Valve maps (BOSCH)

[stevieturbo]

You have huge enrichment values in the idle section. Reduce them to zero for starters. They will be messing with the fuelling no end.

Also turn off closed loop idle until you have at least settled on some decent idle duties in the main PWM map.
Trying to use closed loop on untuned maps will just cause conflicts.


IMO for warm starts over 60degC, very little enirichment should be needed for most engines. Reduce all values to zero and if it needs more, increase slowly.

Also PID settings of 50/50/20 are a bit mad
You can leave P at 50, I should be much much lower and ideally D would be near 0

And having idle control on until 3000rpm also seems a bit strange. There is little reason to have this turned on a few hundred rpm over base idle. Likewise, your idle rpm map goes to 2100rpm, there is no real need for that.
If you're main idle is say 1050rpm, there is little point having an idle map much over say 1400rpm

[iceman_n]

thank you...i will try it

what do you mean "And having idle control on until 3000rpm also seems a bit strange. There is little reason to have this turned on a few hundred rpm over base idle"

[stevieturbo]

thank you...i will try it

what do you mean "And having idle control on until 3000rpm also seems a bit strange. There is little reason to have this turned on a few hundred rpm over base idle"

Why would you want idle control turned on until 3000rpm ? Your engine will never be in an idle situation or anywhere near it at 3000rpm.

[VR6Turbo]

Depends how quickly the engine decelerates. I've often found it helpful to open the valve early (2500ish) with a little fuel and timing (but not so much as the car drives itself with zero throttle) to bring the engine more gracefully down to idle. Opening the valve a couple of hundred rpm above idle simply didn't work. It just stalled 5 times in 10.

[Roverdose]

i set mine to 6k just to see what happens..for me, not a lot. though i do have the first column in the ignition table as 10's. used to have 25's but prefer less engine braking.

i set it to 1's this eve and added a lot of fuel, see if i can get some flames!

Drew

[stevieturbo]

Depends how quickly the engine decelerates. I've often found it helpful to open the valve early (2500ish) with a little fuel and timing (but not so much as the car drives itself with zero throttle) to bring the engine more gracefully down to idle. Opening the valve a couple of hundred rpm above idle simply didn't work. It just stalled 5 times in 10.

Your base throttle opening is too small then.

Unless very large cams are fitted, and even then it should still be ok, base idle speed should be set via throttle blade or damn close to it.

That should pretty much prevent idle speed ever faltering too low.

Idle bypass valves are there in addition to the blade, they are not a replacement. Base settings must always be sensible for any system to work well. The refinements are to do just that, make them work even better

[Simon P.]

Idle bypass valves are there in addition to the blade, they are not a replacement. Base settings must always be sensible for any system to work well. The refinements are to do just that, make them work even better

Not entirely true. My S54 has absolutly NO provisions for opening the ITB's via the shaft. I'd have to manually set each TB to do what you're suggesting. Not really ideal. All my idle control is through the ICV, just as BMW intended it to be. So yes, I also open the valve a little early to stop the engine from dying when decellerating. I tried setting it to a low value but came back to 1500ish with a target of 1150. The light flywheel probably doesn't help either as the revs drop quickly when you're off the gas...

[Roverdose]

The light flywheel probably doesn't help either as the revs drop quickly when you're off the gas...

what values do you have in the first column on the ignition map?

Drew

[Simon P.]

what values do you have in the first column on the ignition map?
Drew

This.

[iceman_n]

thank you...i will try it

what do you mean "And having idle control on until 3000rpm also seems a bit strange. There is little reason to have this turned on a few hundred rpm over base idle"

Why would you want idle control turned on until 3000rpm ? Your engine will never be in an idle situation or anywhere near it at 3000rpm.

3.4 kg Helix alloy flywheel maybe that's the reason...i still not try your advices but i will do it maybe in holidays...