VEMS : revs rpm dropping off when engine loaded

[Jamo]

In already running 1.1.88 good firmware

[A80Avant]

When you get oscillations then the P is the one causing them most of the times. Apparently Matthias also mentioned to me an integral problem which has been resolved on 1.1.88

I haven't noticed it tremendously to tell you the truth, but I will be upgrading soon.

[QuattroFever]

there is one further back in this thread but its not current. I have changed my base settings and adjusted my VE table to gain a higher resolution as was recommended. gone back to the req. fuel that peter supplied me with and leaned everything out alot more.

I will post an updated .vemscfg

[Jamo]

Depends have you got a map you can post up or screenshots of your ISV settings, also remember an unbalanced ve table and ignition will cause the same hunting

[QuattroFever]

its great 99.999% of the time but it seems when it gets warm ~50 -60'c it starts to hunt a little. and when it gets up in the 80's and you sit still for any period of time it starts stumbling. when the fan cuts in etc etc.

if I go higher than those settings like 24-25-26 it makes the hunting worse and if I go lower it cant recover from the fan cutting in. So I'm pretty confident that the settings for P are about right.

The I is at 7 any lower and it doesn't quite make its targets and higher seems to make no difference until it starts to cause oscillation.

D seems to do naff all...I thought it helped dampen the oscillation but when I was curious and took it out it still done exactly the same as it did with it.

maybe I should try another ISV and see what changes.

[Jamo]

Oh no don't give up, tuning idle takes a lot of time, took me months for me to be happy, in the meantime you can disable ISV and run on ignition timing only, A4kquattro has posts on the settings

[QuattroFever]

Im currently using
PID 23 7 0

was using
PID 23 7 170

i though that the high D helped with oscillation but when i took it out it made no difference.

It's strange...you think you've got the settings right and the next time you go for a drive its like its rewritten the rule book!


I've given up. I've resigned myself to the fact that the car isn't OE anymore and can't be expected to idle OE.

although it shouldn't be this way, at least I might keep my sanity.

[Jamo]

It's such a mystery why idle is such a problem on all these cars and we need different settings. I've had to revert back to my original settings on idle with NO ignition timing.

Using ignition timing makes my engine sound awful and no better that just using the IAC with PID 35 3 7 and Asymmetric PID Conf

[A80Avant]

on the 12th of june I will be in london anyway, so that is sooner than MRC. Send me a pm of your email and ill write you a small guide through.

[QuattroFever]

I can stick it out till mrc rr day if you go, it's perfectly drivable and I can still keep tapping away in the meantime.

if we can be drawn away from eyeballing the cars of course.

[A80Avant]

aaa indeed. i will be in london around june time the earliest...

[QuattroFever]

london, bit of a trek

[A80Avant]

that was excactly my effect of keeping the D high. also in my car once the engine temp goes higher, idle was going higher as well and D was making it worse.

if now it is ok,then at least you have a start.

you didnt tell me where you are!

[QuattroFever]

been out for a drive and its not too bad. same as last night. Guess it will need some tweaking to get it spot on. Idle doesnt seem to want to come down to my general idle setting though.

is that the effect of one of the PID? or maybe was a temperature thing made it lower and that why it went up slightly after I went for a drive?

[A80Avant]

It is hot because of the location, not because of anything else. I am not sure if that affects its operation. Probably not.

You are getting there !