I purchased this Miata with no tuning knowledge, and I have been trying to make it run better on my own and learn the software. But I'm still having weird idle issues even after closed-loop. It used to idle and use the target rpm. But I am not exactly sure what happened, it's no longer targeting the rpm . It also started to rev hang after I switched to closed-loop. Didn't do that in open-loop. So I'm sure it's something in the Closed-loop settings. Also If ya'll see anything off or unusual please point them out. I been in a circle these past few months,

 

Just needs to be tuned. Try this one, it won't be perfect but a step in the right direction... should fix the idle hang and bring your target down to a more reasonable 850 RPM.

If you want help tuning it, PM me

 

Yea. It idles but it's still rev hanging.

 

Post a log please.

 

Sorry, I was up at 4 in the morning data logging. I forgot which one I wanted to use. But. All of these 3 data logs should have rev hang.

 

Your idle valve was set to inverted, meaning 100%=closed, instead of the typical open. Not 100% sure what this is going to do with the rest of your settings, so just load this tune, log it again, and we'll go from there.

Edit: this isn't going to affect your idle, but your MAT sensor is doing something weird. Constantly spiking to ~35*f, then slowly falling back to 0. Might want to get that fixed.

 

Oh, i don't have a MAT yet. I have a MAF but it's unplugged. I really want to install an IAT soon.

 

I switched to "invert to normal" on a tune file a tuner shop tuned for me. I was just playing and comparing tunes. (Tune is basically the same as my current one). It started to rev up really high, I even tried to drive it like that to datalog but in between shifts it would just rev up. Also I just remembered, It did the exact same thing on my current tune. I forgot. I did it super late at night. OOps sorry. 

BUT here's the datalog

 

It is impossible to diagnosis a problem with if you're not providing the tune used when the datalog was recorded.

In the datalog "inverted", your idle valve started at 30% (fairly high), and eventually went up to 40%, so if your RPM followed, then it's behaving properly. The tune I attached above had a minimum idle duty of 18% IIRC, again this log never went below 30.

 

My bad, I forgot i did that when playing with tunes. Sorry.
I changed it back to 18.0 for idle valve closed duty.

 

Nice catch @Curly. Valve pegging 18% DC, still lounging around 1100 RPM. Throttle plate may be cracked open slightly due to throttle stop adjustment/junk built up in the throttle bore/cable too tight/etc.

 

Not too long ago, I did clean the throttle body and intake system. Also whenever I first got the car the very first thing I did was adjust the throttle cable because there was a lot of dead pedal play. But I'll loosen it a little and see if that changes anything!

 

Yeah, but at 1100rpm he's idling at 4.5*, later in the log idle advance correction isn't on, and he's at 2500.

I would also suspect either a throttle cable that's too tight or leak in the system.

OP, does your TPS reading smoothly follow pedal movement? You can check this with engine off.

 

I loosened the throttle cable a little and it didn’t change anything but, I was searching for vacuum leaks with carburetor cleaner and i found 4 vacuum leaks. All 4 bottom seals for the injectors leak air. Or at least i think so. Every time i spray on the bottom seal, it makes the engine shake and stumble.

And yes, the TPS does read smoothly.

 

Sounds like you have the cat by the tail

Fix your leaks and give it another shot.

 

We’re so back guys. So the new seals worked. And i had some flow-force 640cc injectors that i been wanting to install. New o-rings, new injectors, new settings loaded into tuner studio. No more rev hangs. It now idles lower and it actually reaches the target rpm. It all worked out in the end.


Thank you Rracer, and Curly.