Matt4186

Hi, long time reader first time posting. My son and I are trying to figure out why our 1.6 turbo Miata is cutting out at 6200 rpm. seems like the rev limiter but more abrupt. I tested the rev limiter settings its working. even with the rev limiter set to 8,000 same result.
Things I have tried, Wired waste gate open to see if its boost related, no luck, its just not as violent with no boost.
Tried Irdirum plugs, gapped to .025, NKG R ..025, .030 gap
Thought it was ignition so went to ls coils, no change.( runs better)
Not using any boost control, so no limit there, just rev limiter.
has upgraded fuel pump and injectors.
I did a 3000 rpm pull and logged the data, but were new to tuning not sure what to look for.
I also included the tune as well, we are open to taking to a dyno session just feel we should figure this out first.
it runs great just hits a wall a 6200.

The car was setup when we purchased it, we just did a refresh and new turbo, and turbo smart waste get 12 psi.
DIYpnp mega squirt, latest updates, I did read in this forum to try and reflash have not tried it yet.

Thanks for any help

Kboi12

You said boost control is off but overboost protection could still be on.

natewin

TLDR:
#1 Your VE table is overfueling ike crazy. Fix this and you should fun fine.
#2 Set to Stoich to 14.7 in General Settings.
#3 Confirm your reqfuel is correct for your injectors in Engine and Sequential Settings. You are at 7.3 currently.


It looks like it is going extremely rich when you are cutting out, like all the fuel is going in and putting out the fire. Looks like this is the problem, you are doubling your VE value right when it cuts out. Look at the log yellow line jumping up and your AFR nosediving.
It seems like someone has auto tuned this and never was able to get above 6k ish. That is why there is a low trough in the VE table where fueling has been pulled. I have circled the high spots where your car won't be able to even run, and you have proven that.
Hit 3D map button and it kind of tells the story. Autotune has been pulling fuel out but can't really keep up with such a drastic change, even if you tried is my guess.

One odd thing is you have Stoichiometric AFR set to 12 in General Settings, I'd start by getting that set to 14.7. Your AFR target table looks fine enough.
Also confirm your reqiered fuel is correct for your injectors in Engine and Sequential Settings. You are at 7.3 currently.

The whole thing needs a good VE tune, but your tuner should be able to fix it if you are not comfortable doing so.
I'd say there's nothing wrong with the car other than VE table and IDK how the Stoich value affects tune, but I'd at least put it to what everyone else uses for the most part.

Other considerations:
Might as well get on latest firmware if not. Remember to unplug injector and ignition harness when flashing.
p.s. it isn't overboost protection, but maybe turn that on.

Matt4186

I checked, no over boost was set.

Thanks

Matt4186

Wow thanks, you are correct we were trying to auto tune. I will make these changes and get you an update

Matt4186

Thanks so much we were struggling with this for a long time. I was off on my required fuel to.
corrected theses and did some pulls to 7500 no problem seems to make more power too.

natewin

Glad it is sorted!