Idle issue on Vems.

[popdemonic]

anyone please give me some insights about Advance rate of change?

if the RPM stays ways above 900-950rpm then everything is way just fine.no oscillation,no partially drop when let off the gas.

when i looked up my log i found once the rpm dropped suddenly,i noticed the spark table on the bins was changed from 14deg to 25deg.

this's kinda weird to see much changes on the spark timing.



on the photo i use 24Deg,presently,i dialed it back to 8Deg.I seems a bit helps.

[prj]

anyone please give me some insights about Advance rate of change?

if the RPM stays ways above 900-950rpm then everything is way just fine.no oscillation,no partially drop when let off the gas.

when i looked up my log i found once the rpm dropped suddenly,i noticed the spark table on the bins was changed from 14deg to 25deg.

this's kinda weird to see much changes on the spark timing.



on the photo i use 24Deg,presently,i dialed it back to 8Deg.I seems a bit helps.

24 deg is too much. You will surely pass the optimal timing limit, so it would have the opposite effect, of what should happen. The max. advance you should have at 600 rpm should be 16 deg. This might also be the reason for your problem.

Try turning ignition based idle off, set the advance at lower bins all to 8-9 degrees.
Now tune PID so the idle is more or less decent. After this is done, turn back on ignition based idle.
Try setting max. advance to 8 degrees, max retard to 8 degrees, threshold for activating IAC to 3 degrees, advance rate of change 12 per 256.

Make sure that before you tune idle, that your VE map is tuned correctly and your fueling is good. If your AFR dips to 17 at 700 rpm, or something else like that, no amount of fiddling with PID/timing will help, so make sure everything is good first.

[popdemonic]

Thanks Dmitri,I will try top give it a shot.

Now the idle is almost perfect.only occasionally,

the RPM sticks at lower RPM(680-700RPM).I just give it a little

gas,the RPM will catch up well.Now I got the idle w/ AC on at 890-900RPM.

I'd like it to stay little lower since I'm driving my car in Bangkok.most of the time,

the car will be idling.

[popdemonic]

one thing,keep in mind I have Dr.Schrick camshafts on AAN.Any effects on tweaking the idle?

one of my friend(Krieng) is running RS2'd with VEMS on his car. He can get almost perfect idle with similar

tuning.

[prj]

one thing,keep in mind I have Dr.Schrick camshafts on AAN.Any effects on tweaking the idle?

one of my friend(Krieng) is running RS2'd with VEMS on his car. He can get almost perfect idle with similar

tuning.

Oh, if you have Schrick cams, then you will have to idle at around 1000-1100 rpm.
Why do you have Shrick cams? What kind of turbo are you running now? GT35R?

If you have the GT2871R still, then fit stock cams, it will be much better in the range the turbo is designed for on this engine, and you will be able to keep stable idle of around 750 RPM.

[popdemonic]

I had Motronic with Dr.Schrick cams and idle was doing flawlessly.

I have gt2871r Ar 0.63.I suppose that should be fine with VEMS as well but it

might a fine/proper tuning.I wish I could live in UK right now.

[prj]

I had Motronic with Dr.Schrick cams and idle was doing flawlessly.

I have gt2871r Ar 0.63.I suppose that should be fine with VEMS as well but it

might a fine/proper tuning.I wish I could live in UK right now.

What I mean is, that with a 0.63 A/R GT2871R those cams are probably making your car slower...
But regardless, you should do one thing at a time. If you disable ignition based idle, set the map to 8 degrees, and then tune the PID for the ISV only. Do you still get the problem?

Are you sure that your ISV valve is working 100% correctly? It could be sticking?

[Thuppu]

I would buy the Schricks if you are selling them.

[popdemonic]

What I mean is, that with a 0.63 A/R GT2871R those cams are probably making your car slower...
But regardless, you should do one thing at a time. If you disable ignition based idle, set the map to 8 degrees, and then tune the PID for the ISV only. Do you still get the problem?

Are you sure that your ISV valve is working 100% correctly? It could be sticking?

Yup,I had Dr.Schrick cams in my car when I had the automatic box and stock Motronic

with 034 dedicated software for GT2871.One thing i noticed is i lost some of the low end

power with Dr.Schrick Cams but seems gaining some slightly at the top end.It ain't

problem to switch the camshafts to stock.I can ask my mechanic to get it done within

few hours.iirc, the shrick cams have 260 deg.is it too high for AAN.I think this

camshafts might be orginally for n/a 5cylinder since i noticed there's distributor

gear available at the end of the intake cam.I have 3 used ISV.anyway,it's used how

could we know if it's still 100% functionally.I'm taking that into account to replace it.

I'll try to tweak on the ign base idle page. regarding to your advice Dmitri.

[popdemonic]

Thuppu,

Did you get your car started?my Dr.Schrick Camshafts only have a few thousand Kms on
them.

[popdemonic]

i have tried on your configure. they're all do the same once the rpm hell down,i tried to switch my configure and yours on the fly.they're all the same.

I popped up the hood and using the big rock it on the isv,no worky.something must be going wrong.

[popdemonic]

correction### I use the big rock hits on the ISC body with hope i could be sticking.no Luck finally.

[prj]

Did you try with ignition based idle turned off?

[popdemonic]

definitely yes.firstly everything seems to be great once i turn the steering wheel left and right.the RPM suddenly drop to 600 RPM and it won't turn back

to 860 RPM anymore.I see the the timing advance to 25 deg at 600 RPM.I tried to rev the engine up.no woky just back to 600 RPM.it's kinda weird.

[prj]

definitely yes.firstly everything seems to be great once i turn the steering wheel left and right.the RPM suddenly drop to 600 RPM and it won't turn back

to 860 RPM anymore.I see the the timing advance to 25 deg at 600 RPM.I tried to rev the engine up.no woky just back to 600 RPM.it's kinda weird.

So, if you turned off ignition based idle, and timing advance is going to 25 at 600 deg, then it is something else interfering.
If you are turning the steering left and right, and it's dropping, your PID is not tuned right.
Lock your timing in place(!!!), then tune the PID.