VEMS: the unstoppable pulsing idle

[QuattroFever]

as in the title. Trying to iron out the idle.

All idle controls off and still it pulses 1000-1200.

[A80Avant]

what firmware are you using?
check that your spark is not pulsing between 2 values

[QuattroFever]

1.81
Ign and fuel bins are all the same around idle.

[QuattroFever]

and i can lower and steady the idle by using PWM but its crap to drive because i have to set the duty to the same min and max to hold it.

[A80Avant]

i just started using 1.81 today so i cannot be definitive about this

instead of 25hz that marc sent it with, i use 250 and have about 26-28 on PWM at the moment.

seems fairly steady for a warm engine

[Nik0las]

sorry for the off-topic, but your using VEMS what is hapening with the MAF? It's useless right? Does it inludes map sensor and boost control?

[A80Avant]

yes

back on topic, changed to 125 now for a test

[Billman]

Try the settings I have (find it in the Vems maps sticky). Also turn ego correction off till 1500 rpm and set the VE correct. After that enable again.

[Jamo]

Likely your ego is causing it to fluctuate, what are your ego settings?

[QuattroFever]

left this for a while...been tinkering.

peter gave me some PID settings to try that seems to help a little with the revs dropping off but still didnt cure it.

my lambda target is 1.06 below idle to give me a little oomph if i dont dedicate enough right foot to pulling away and 1.00 on idle

ego is 30% rich and lean limit and step size is 3 i thunk?

running the ISV at 75Mhz ---> 250Mhz is that ok? I read somewhere that motronic runs it at something highbut didnt think that high.

I've been messing with the IAC ref. curve and min. duty %

I've managed to get what seems to be a stable idle at 1050-1000 rpm, doesnt want to go any lower using about 24 min duty and even then sometimes it goes to 1100 and wont budge. If I leave it on 24 min duty then the revs drop off when i dip the clutch after cruising and if the fan is cutting in as you pull away then it's kangaroo time!

also, no air leaks.

Try the settings I have (find it in the Vems maps sticky). Also turn ego correction off till 1500 rpm and set the VE correct. After that enable again.

Cant find an options for ego activation at set rpm are you on 1.81. I get what you mean and tried setting VE with ego correction all settings to 0...no joy however. starting to wonder if the stab valve is goosed.

[prj]

my lambda target is 1.06 below idle to give me a little oomph if i dont dedicate enough right foot to pulling away and 1.00 on idle.

Why would you run so lean below idle?
You should enrich, to about 0.94-0.96 below idle, not lean...

[Billman]

Cant find an options for ego activation at set rpm are you on 1.81. I get what you mean and tried setting VE with ego correction all settings to 0...no joy however. starting to wonder if the stab valve is goosed.

Go to "Base Setup"
-EGO CLosed Loop Control
Under Conditions for enabling : Minimum RPM.

Post your Config File so we can see what you running with and make suggestions (post also Setup details about Injectors, Capacity ect).

[th.b.w.]

Show us your configfile please....

I don't use PID idle, only ign. based and it is very stabile with it !

Thomas

[QuattroFever]

Show us your configfile please....

I don't use PID idle, only ign. based and it is very stabile with it !

Thomas

i was using ign based idle along with pid and wasnt making much diff. maybe i have it setup wrong.

Why would you run so lean below idle?
You should enrich, to about 0.94-0.96 below idle, not lean...

it was rich to begin with as I understood thats how it was supposed to be but running rich down there seemed to make it judder and jolt about when I lifted the clutch without trying to slip it. When i leaned it out it helped massively, so I left it. Maybe that points to something else being amiss.

will post config.

[prj]

Considering all I5 cars are mapped from the factory to run richer below idle, I'd say something is wrong.
If I map my car too lean near idle, then there is hesitation - like something is holding the car back, when you are starting.

I am not really familiar with VEMS, but could it be that your injector latency compensation is configured incorrectly?