jwrinkle

Hello All,

i have a Miata nb1 with MS3x. I recently finished my turbo install, loaded the ms with the trubokitty basemap, and went on my first drive.

When i “roll” into throttle, I get a misfire that prevents the car from revving. It sounds like I’m getting fuel or spark cut. I datalogged my drive and have been pouring over all the data to see if I can locate the issue. I honestly don’t know what to look for. I can’t see any evidence of spark or fuel cut on the log.

Anybody have any suggestions?

ive researches this for 2 days trying to figure it out on my own without asking for help. I’m stumped!

Also, making 12.2 psi boost. Way to high to be safe on my current tune, so I’ll be addressing that next.

Best,
jw

jwrinkle

curly

iTrader: (25)

Post your tune and attach a log, not just a screen shot

jwrinkle

Tune attached. Trying to get the log attached.

Thank you!

jwrinkle

Update -

Drove the car again and recorded 2 short logs of the issue. I'm using the basemap timing, could this be the issue?

curly

iTrader: (25)

The 2nd log almost just looks like a misfire. What's your ignition system, when were the parts replaced last, what are the plugs gapped to, etc.

jwrinkle

Thank you for looking at my log, curly.

Ignition is stock for now. I’m going to try a plug swap, and hope it fixes it haha!

What data indicates a misfire on the log? I’m trying to figure out what I’m looking at on MLV so that I can hopefully identify problems in the future.

Thanks again for for your help!

curly

iTrader: (25)

New NGK BKR-7s and gap them down to .025" or so.

I didn't see anything after a quick look at first log you posted in post #5, but in the 2nd log, the RPM looks like a saw blade, that indicates it's misfiring, and you're not getting power on 1, 2, or 3 cylinders. This uneven firing takes your smooth RPM curve and makes that saw like curve you see. It's right as you pass by 160kpa, or 9ish psi, so I'm guessing your plugs/coils aren't up to the task. If you haven't replaced the wires with NGK blue wires in the last 20k, do that now. If this is a 99-00 and haven't replaced the coil packs in the last 24 hours, do that now.

jwrinkle

Well Sir, you were correct! I replaced the plugs with BKR7S and gapped them at .025. Went for a quick spin and SMOOTH sailing! It is a 00 with stock coils though, so that's in my shopping cart.

It's ridiculous that I didn't think to graph my RPM on the logs. I was looking at TPSdot, fuel pressure, dwell etc and totally missed the obvious.

Thanks for your help!