Anyone using 3-wire Idle valves?

[VR6Turbo]

Interresting tidbit I found; many people think that the 3 pin ICV's have no return spring because the valve movement/position depends on which side is pulling to ground but that's not quite true. Although the spring is very soft in these, there's still a default position at which the valve returns when not powered. Case in point; if my engine is running and warmed-up and I unplug the valve the engine always defaults to 1400ish RPM. Everytime. And I've tried it quite a bit while playing with idle parameters. Then I if I reconnect, my idle drops back down to the programmed 1150.
Hope this helps

Interesting. Now I remember, the 3 bin Bosch on my M50 engine seemed to loosely centre itself too. It is indeed a very weak spring compared to a 2 pin. Maybe the 1400rpm default is a 'limp home' feature most OEs like to engineer in?

[Jon K]

It may be because of vacuum but the valve on the bench definitely does not have any default position. At least mine doesn't!

[Jon K]

Got her running. Hooked the "fast" pin up to the opening pin of the idle valve, and then set up some base figures.

https://vimeo.com/39947352

Simon if you want to share your settings that'd be great. So far I have it running decently, but it needs tweaking.

[Simon P.]

Hey Jon,
Glad to hear things went well. I really like how your idle is very stable even with the throttle blipped. Mine is very close to that when warmed-up but has a tendency to "hunt" when cold. I have a feeling the base PWM and PID limits are fighting each other but I haven't had much time to investigate. How's yours when starting from cold?
When I started playing with the original idle settings things were a bit rougher as even when warmed up if you touched the throttle it would start to hunt for 4-5 seconds then stabilize. I was able to smooth it out quite a bit but it's still not 100% perfect.
Anyway, here are my settings. And also a picture of the valve arrangement. I've deleted the BMW intake piping for the valve as this simplified fitting the VAC airbox. Maybe the smallish AN fitting you're using on the intake side is also helping to make the valve more controllable as it's creating a restriction on the intake path, much like the stock piping arrangement did...

[VR6Turbo]

Looking at your map there, I would recommend you slow down the control loop and reduce the prop.

Also you have PWMs that increase as the revs fall. This I have found definitely causes hunting in DTA land. Aside from the cranking rpms where you can have 100% duty, I find keeping the PWMs the same number thereafter massively reduces hunting.

I have spent 5 years with my P8 and S80 trying to master idle, with 3 or 4 different valves and now DBW. I have finally settled on a P of 15, I-1, D-0 and a 2 second control loop delay. Sure it's slow, but it works and the car idles and drives like stock. I can lift my foot off the clutch when cold and it'll pull itself along in traffic smoothly with no gas pedal, just like stock.

[Jon K]

Sweet man thanks for posting, both of you. I will take a look tonight and try some of these figures out.

[Page]

Hi,
these are my current settings of Bosch 0 280 140 505 valve .



The thing is that i have to set the Idle Base PWM Map but seems not working !
I think it should be show a trace from where is but stays constantly grey to the 0/200 cell (the very first) .
What am i doing wrong ?

And despite that the idle speed is set to 1100 rpm on the Idle Speed Parameters, this keeps working very low at 780-850 rpm .

thanks in advance
Geo.

[Page]

Anyone ?

[stevieturbo]

Dont understand the question ?

So idle control is active ? And you can change the values of the PWM table from 0 to 100 and nothing happens ?

[Roverdose]

says in that setting page that max duty is 8%, that isnt going to do much.

Drew