Idle control on specific conditions

[mattias]

If you momentarily disconnect the T-piece that connects the MAP sensor to the intake, then that will make the MAP sensor see atmospheric pressure and the intake actually has idle vacuum and the engine will run very rich and stumble.

The FPR, boost gauge and ECU MAP sensor don't need "flow" in their lines and can be connected to the same line. Generally these are also considered quite vital and if possible they are given their own signal source, but do it right and you should be ok.

The Motronic heavily relies on the AFM, the MAP sensor and intake temperature sensor (speed-density) are secondary in that case.

Good luck with the testing!
It's better to make decisions once you have tested more.

Unless you have done a proper intake pressure test, you should. I posted this which I wrote on another forum :
http://www.vemssupport.com/forum/index.php/topic,1451.0.html

[AVP]

It is not easy for me to do the whole method for intake leaks. I have looked for boost leaks in the past and also all of the intake pipes and intercooler have been checked recently.

My problem exists after the throttle valve and the means the manifold and all the vacuum hoses connected to it

[AVP]

I rerouted the vaccum hoses and checked them. No leaks there. I now have a dedicated line for the ECU, separate for FPR, separate for PCV and the one that goes to tha carbon canister, i used for the methanol and dump valves.

i redid the PW reference curve and idle works fine, BUT still need to keep it at 30DC in order to achieve my 950rpm.

I did not check the ISV valve by blocking the hose there, as its too cold to try, but i think my problem is the throttle plate. When i had it machined to 70mm, i distinctly remember a small area which was always open, even with the valve totaly shut, so i think i may have to have a second one made.

[AVP]

On one more test and ride, i noticed that the idle is sort of keeping at bay, at no more than 1000rpm even on higher IAT (34+) and that is good at least.

Vems is manipulating the valve as it should and does not need to be inverted. I think that if i manage to make a second TPS with better seal it will solve the problems. We shall see...

[AVP]

i managed to see the log file Peter. Thanks for that,but i cannot use the settings you have, as due to the throttle body flap issue(i believe), if i use 41% DC for the warm area, i get about 1100-1150rpm idle speed.

So ill stick with my settings for the time being and wait until i have a second throttle body fixed and fitted.

[AVP]

im going to fiddle around with the TB tomorrow as i think i can adjust it a bit more if i modify it slightly...

[AVP]

after a bit of fiddling, i ended up going from 30 to 33DC on the idle curve. I think that is ok for now.

[AVP]

a small update

idle is very good now 99% of the times.

after a bit of testing today though i noticed this.

Although PID works on most occasions with minimal dip of the needle when offset of idle( ie small blips of the throttle), and with electrical load as well one, i tried this: i turned the ignition based idle off, and the idle even without the press of the pedal was slowly going off balance, and ever so slightly trying to oscillate.

I believe this is down to PID settings and it would require more PID fiddling, but if i fix the PID somewhere where it is ok for the idle then, would turning the ignition timing idle on again make a difference? would it be more stable?

Is this the way the idle should be tuned? or with the ignition timing ON always? and then PID tuning?