Krautastic

I just installed MSPNP2 from 949racing on my 95 miata. It's totally stock at the moment with the exception of the GM IAT on stock intake tube (cone filter at end) and a PLX/innovate wideband in the stock exhaust.

I'm running the mm9495 base map from diyautotune and finally got the car to idle fine by adjusting idle warmup duty (had a number of issues where it was idling low), but I'm getting a lean spike on throttle tip in and the car runs rich (afr target reads 14.0 at idle, but it's idling at 13.0). I've read about VE tables and acceleration enrichment as solutions to these issues, but I don't know much about these and don't know if there's a step in between that I'm skipping.

The long term goal of the car is it is receiving my flyin miata ubercharger with RC440 injectors and full exhaust off my 1.8 swapped 92 bag of bolts which is running a LINK ecu. That car was built and tuned by someone else and I never had to bother modifying the tune. It's a piece meal project where I am trying to test smaller variables at a time. The next step is clutch upgrade, coolant reroute, radiator and intercooler mounting, which I will then run NA with the interfooler in place to test air flow around town so that I can understand any reliability issues before the final step of installing the power adder (ie: if it can't cool the NA motor, I'll know I'll have issues when it's boosted).

So I'd like the car to run reliably in the meantime using the MS, and I imagine what I learn here will help once the injectors are installed and the tune needs a big update. What are the next steps I should work on, especially to cure the rich behavior of the car? Is tune analyze live a good purchase for a novice tinkerer (I will be taking the car to an MS knowledgeable tuner once the supercharger is in, but don't know if it'd be something to help in the meanwhile. Thanks! I appreciate in advance the very newb question.

EDIT: Log and tune attached. Also, I guess my idle issue is not resolved, as the car doesn't want to start when warmed up unless I open the throttle and it wants to idle at 600rpm at times. I may have to crack open my IACV some to get more air in, but you can see in the log some of the lean tip in (enough to buck the car) and the how rich it drives and idles.

Krautastic

in the spirit of using the search button I'm using the mx5nutz guides for setting closed loop idle now. Then it looks like autotune should be implemented to get the tune in better shape.

Matt Cramer

I noticed the MAP sensor is reading 82 kPa - do you live at high altitude? You may have a bit too much barometric correction being applied.

You will first want to get the main VE table dialed in to match what your engine needs, then you can start adjusting the acceleration enrichment for tip in (if it still needs it at this point).

Krautastic

Hi Matt, appreciate the response! Yes I am at high altitude (colorado). I think I've seen this setting somewhere, but what should it be reading? Checked the weather today, and barometer is reading 101kpa, so the correction is pulling my reading down too far?

I replied to a thread on m.net trying to help someone else with idle issues. But the steps I've taken since originally writing this post were based on the mx5nutz guides to setting idle without IAC correction (unplugging it), then adjusting fueling until it is at stoich and idle is stable (mine fluctuates about 30-40rpm, but nothing I do seems to change that and it's an idle fluctuation in the software, not really noticeable through vibration/noise). I was able to get the car idling well with a goal of 900rpm warm and 1300 cold. I then closed up the IAC screw to idle at 740rpm, reconnected IAC. When I went into closed loop idle control following the mx5nutz guide again and set target idle of 900rpm, it seems to idle leaner even at the same rpm when the IAC was disconnected and screw backed out to idle at 900rpm. So I added 2% fuel to all cells in my idle range which brought it back down. I am noticing a .3AFR difference from gauge to software (software shows leaner than gauge, WBO is grounded at the throttle body/ecu ground point so I don't know why the shift is there. I also boosted my cranking PWM to solve my issue with the car not starting after warmed up. I am slowly coming to terms with things, but it's not a learning curve, more of a learning wall that I have to hit my head against a bunch of times before I figure my way over.

Lean tip in is improved but not eliminated. It looks like the next thing I should be doing is downloading the full version of tuner studio and use VE analyze and start driving the car to adjust the VE table else where? My thoughts are that after I have an understanding of getting to that point on an NA tune to move over the new fuel rail and injectors to get all this stuff sorted out again before I install the supercharger to keep my list of variables low.

Matt Cramer

Reduce the barometric correction at 80 kPa until your AFR is where it needs to be.