Thread: Rough, Unstable and sometimes high idle!

Yeah, that thing, PNP is what I ment.

I increased the knock voltage, be wise to monitor voltage and make adjustments as you see fit. I disabled idle RPM timing table, this will help the final ignition stabilize. I also turned off closed loop and increased your injector battery offset a bit to compensate since you said you did this before and it was lean.

The knock voltage limit tables are correct for the S13 SR20DET as the knock sensor is calibrated differently!

I also sent you a revised TCD via email with an updated battery offset table and lowered the idle ignition error table.

Although, these tables were actually doing their job in lowering your idle as it was close to the target.

I still think your issue is with your IACV.. if you notice during the entire log your idle duty is 10% which is the minimum percentage. This means that the engine is getting enough airflow to idle at 1000 RPM even though the idle duty is at it's minimum. This means either your idle valve is faulty, leaking OR air is entering around the throttle body by another means!

The reason your idle goes UP when you add fuel is because with that large of an injector the engine will struggle to idle at 16.0 AFR and adding fuel will make the engine more responsive and will cause the idle to go up past your target. Since the idle valve is already stuck at it's minimum or 10% .. it can't lower the idle by any other means except by pulling timing.

Can you post the TCD. I like to hoard bins and tcd's. You are probably right about the IACV though, but if it was faulty, how is the valve adjusting when the throttle was brought up a bit? Also, what is the deal with the knock table, the entire #1 cylinder values are maxed out? And, only when the throttle was brought up, the final ign actually stabilized at 15 degrees, then went screwy again when back to idle.

That is because if you look at the idle valve tables there is a min duty cycle #1 1 is inhibited by something for accurate knock readings and hence why that table is basically zeroed out.

It seems as though cylinder #1 has something that inhibits accurate knock processing by the way it is calibrated from the factory. (Too far away from the knock sensor and possibly some other sort of engine noise?) @OnTheChip might have a better explanation.

Once the throttle opens, the idle ignition error adjustments stop having an affect and it then starts to rely solely on the actual timing table for the timing value.. you can watch the idle ignition trim go to 0 once the throttle opens.

I've suspected my valve has been faulty, and behold it doesn't seem to be getting a signal from the ecu.

Next job, rewiring it from the ecu direct. I also dialled down the ignition correction values to a maximum of 2 degrees, don't know how badly it will affect driving idle, but sitting in driveway idle is way less hunting.

In order to check the aac, take a look

https://www.google.com/url?sa=t&source=web&rct=j&ei=A-jLUs22NOvMsQS06YKADg&url=http://forums.nicoclub.com/iacv-aac-cleaning-and-testing-tutorial-t251133.html&cd=1&ved=0CDkQFjAA&usg=AFQjCNGfwGiOq-Tl7Lu79DR8zMw33N9EcA&sig2=VCIyeh3SPtEbjTiHynYYiQ

Charles update on this??

Not really Boost, I did get a replacement IACV just waiting for it to come.

John sent me an upgraded TCD with some revised changes but needless to say the issue persist and it's running lean as well..

I recorded some logs but forgot to save before I exited out of NEMU..

So I should have my IACV and MAP sensor in Wednesday or Thursday and at that point I can diagnose further...

I will only be logging with the map sensor and nothing more at this time until I convert or run a dual SD/MAF setup..

btw Boost my invitation to come past is still open LMAO!

Oh I haven't forgotten about your invitation

I am trying to finish up with my idle issues as well (I pretty much have a handle on it as I have the idle AFR correct, wideband (finally) working, and a few other things). Once I am done (now the only issue left is idling high, which I think the idle screw is screwed pretty much all the way out), I will try to come by!