18tyweslow

Hiya fellas. I fully expect to get roasted here, but I'm coming to you in my time of need. I got my turbo NA8 tuned last week. It seems like it runs pretty good, and pulls hard. 232whp/213wtq.

1997 Miata
FM Turbo Kit w/ ID1050x injectors & MS3Pro PNP from DiyAutoTune.
FM Coolant reroute & Supermiata radiator (no wiring was modified for AC/Cooling system)

But I'm having some drivability issues that I'd like to try fixing myself before taking it back to my tuner (I have been in contact with him and he's given me some pointers, but figured I'd get opinions here too)

When slowing down, and I depress the clutch, the RPM's tend to jump up a bit. This makes revmatching difficult as the RPM's rise then fall, instead of just falling. This also makes getting started a little difficult as it's tough to modulate things when the RPM is all over the place. It also occurs if I'm just sitting stopped and touch the throttle any tiny bit. RPM jumps to 2000+ then slowly falls, which is shown in my log.
I know this is almost certainly idle related. My tuner said he did what he could to dial the idle in, but just really had me down for a dyno tune and nothing else. Which is fine, but the drivability kinda sucks like I said. He mentioned turning down the base idle screw on the IACV and upping the base idle duty %.

I also noticed that viewing the logs, the car never "warms up" and is always on "Warm: N", despite the CLT temp meeting the requirement. This coolant temp strangeness also follows with the fan control. The main fan never turns off. It just stays on throughout the entire time. My AC also always stays on, so I just unplugged the compressor until I can fiddle with the outputs, as I'm sure that's what the issue is. I want to say it's stuck in some warmup enrichment state. The idle is a little high, and the car is pretty rich when idling, which supports this as well. I was going to try setting the idle by myself following some of the guides on here, but first I'd like thoughts.

Attached is my .msq and the short log I took while slowing down, then stopped and touching the throttle a tiny bit.

If anyone has any recommendations for me, I'd gladly hear them. I'm very new to this, so hoping I can get some knowledge bestowed. Thanks!

tshea113

Have you tuned your closed loop idle at all? Your initial values table might need some work if its shooting up when you tap the throttle at idle. This site has a lot of good info for getting that stuff dialed in: Mega Miata: Closed Loop Idle REV 2.2

"Warm: N" means the car isn't in warmup enrichment, so that's expected.

curly

iTrader: (25)

There is a large difference between paying someone to tune your WOT areas on a dyno and complete tune. Your dead time is wrong, your small pulsewidths are wrong, your idle ignition correction isn't helping a lot, your EGO isn't tuned well, and your idle fuel isn't tuned well, that's probably just the beginning. I'd love to see a pull to red line logged, in 3rd gear or above, to see how well the WOT stuff is tuned before I completely throw the tuner under the bus.

Edit: to give you an idea, you're targeting 14.7 afr at idle, which is great. But EGO is pulling 20% fuel, and you're still running at 12:0 AFR. You should be able to take 40% fuel out of your idle cells and still idle at 14.7. That also means you'd be idling in the 18-19 VE range, which isn't right, that has to do with your injector settings AFAIK.

Seeing as though your target base idle is somewhere around 845, but in the log it says 995, I would say your AC is active, which raises the idle 150rpm. That also explains why your fan is always on, since it's programmed to be on with AC. This also raises the idle duty by 12.2%, which as far as I know affects initial duty. So by simply unplugging the AC compressor, you've taken the load off the engine, but none of the idle changes the MS is making to compensate for that load, so I would start by fixing that, then addressing some of your base tune issues like injector settings, then tune idle, then retune WOT areas, and probably VEAL the rest of the fuel table too.

18tyweslow

I got the car tuned by Andy Smedegard at ASM, which I thought was a super reputable guy. He's the K swap guy, and is fairly close to me (hour and a half away). Also was on Gears&Gasoline swapping one of their cars if you watch them at all. Bummer seeing that this is such a shoddy tune.

I found this on ID's website: https://help.injectordynamics.com/su...942-megasquirt - This looks like the info I need. I'll update my injector settings with the corresponding 1050x information found here after I figure out the AC.

After that, maybe I should see if someone could e-tune my car, or I'll take it to a different shop. I can do my best to get these things corrected but would prefer a professional to take care of it. This really puts a downer on things, sucks knowing I made the wrong choice of shop.

curly

iTrader: (25)

You didn’t necessarily. Most tunes should cost $1000-1500, if it was a couple hundred, you paid for WOT tuning and dyno rental. Keep in mind changing dead times and the rest of injector settings will drastically change your fuel table needs.

18tyweslow

It was about $500. So that would make sense. I'll reach out to a few shops and see what lead times look like. In the meantime I'll finish up fixing the AC, and a few other interior bits. Thanks for the advice Curly.