Stutter at 5k and I just can't figure it out.
 

Ok, so I have a 99 Miata that I swapped a 04 MSM engine and turbo into. The motor is stock, Turbo is stock, stock IC and pipes, AEM Short Ram intake.
All in all, the car runs great! Except for 4500-5k RPMs. it FEELS like I am blowing out my spark. I put in new plugs, Gapped them to .024 as suggested on here... But still, it feels like I am blowing out my spark. I am using the MSM coils.

It has been suggested that it is an issue with my tune, but no matter what I do, I can't seem to correct it. I have taken a data log of it when this is happening and posted it along with my tune. I would VERY much appreciate if someone could help me solve this issue. I am not above bribing someone to assist if need be :D

I am a complete newb to the Megasquirt. I bought a DIYPPNP for the 99-00 and built it myself. Soldering I can do... Tuning on the other hand.. I am still very much learning.

Please, some assistance if you would! My local guru is stumped.

Thanks!
Randy

What is your overboost protection set to

It is currently set at none.

None as in it's disabled? Cause 4500-5000 is when msm's usually boost creep

*edit: is that a composite log you posted? LOL

Dammit... So it is:D This is what happens when I get to work before Chick-Fil-A opens to give me my tea!!!

I will get another log in a few minutes :D

And yes, it is disabled. We turned it off a couple weeks ago to see if that was the issue. It wasn't.

There we go.. That should be the right log:D

I assume it revs up just fine without boost? That would point to a tune problem.

Spark-blowout should show up as lean-spike in the AFR, since you'll have unburned oxygen in the exhaust.
You are running pig-rich though. Maybe too rich? Hard to say.
I noticed that my AFR gauge certainly isn't very linear. Meaning that my AFR reads for example 10 and I want to reach 11.8, I should remove about 18% fuel- correct? In reality I had to remove more than 30% fuel (corroborated by shorter injector pulses) in order to get from 10 to 11.8 AFR.

So my suggestion: lean it out and see if that helps.

Yea, without boost it revs fine. And once it starts that stumble, if I get off the gas, I can ease it past 5k, where it will run great again. But at WOT it will just stumble all day long, never getting past 5k. Except in first gear. I assume 1st is just so short it blows right thru the stumble. When it DOES get past it, my boost hits like a hammer!

I had an issue that sounds similiar. VICS solenoid control. Mine happened to just be the vacuum hose connected to it.

/\ That makes a lot of sense, actually.

See attached, I fixed it. Your fuel table was wack, causing a rich misfire in the area you mentioned. Also, your timing table is kinda questionable too but I didn't touch it. Anyways, load this and use VE Analyze to get your fuel dialed in.

Based on your fuel map and spark maps, I am going to suggest that you stop driving the car and tow it to a tuner. The fucked up fuel map is a blessing in disguise, because if you do WOT pulls on pump gas using that spark map, you will blow the motor up almost immediately.

Good to know! Most of that was done by a local tuner. However, my transmission took a dirt nap this morning, so I guess it is parked for a while.
And Thanks Pat, I will check out the changes you made once I have a new transmission in it.

In a couple weeks, when I have another transmission in it, I will grab one of Brainiacks base ign. tables and start over on the tune.

I had initially thought it was the VTCS as well. But it is unplugged now and I don't seem to have any vacuum leaks. I even went the extra step of replacing every vacuum line on the car in the swap.

Doesn't matter if VICS or VTCS is permanently connected or disconnected. Tuning the fuel map would adjust for that. (I'm not 100% sure what the VTCS does, but I know a cold 2003 engine does not develop ANY power below 4000rpm or so).

Erratic behavior points most likely your tune, which we already know sucks.

MSM engines don't have VVT-correct? So that can't be it.

Anyway, please post the name of the tuner who did this to you. Let's make sure all other forum members can avoid this utterly incompetent idiot.

I'd love to tell you the tuner's name.. Except I didn't pay for the Dynotune. It was done on a buddies car, which is pretty much an identical setup to mine. However, he doesn't have the stumble. And the only difference is mine was changed for the 99-00 specific stuff, as his is a 96.

:facepalm:

You are failing SO hard.
Leaving this thread because it's progressively getting more retarded.

I fail to see how sharing a tune done on a Mazdaspeed swapped 96 onto my Mazdaspeed swapped 99 is failing. Other than the fact the tuner was obviously an idiot. I see tunes shared on here and other forums all the time.

By people who have no clue about what they're doing, and are also idiots.
It's one thing to share tunes to show references insettings and for people to see your tuning strategy or approach, it's a whole 'nuther thing to actually load said tune and just "use it" blindly, and that's assuming your car was identical, which it's not. A 99 has completely different wiring setup from a 96, even if the engines swapped are the same. The fact that the tune was garbage to begin with is just icing on the cake.

I say all this not to simply belittle you, I'm 100% serious here. I have nothing to gain from your car running like crap.