I'm on the edge...
 

I'm so close to investing in an ECU but for the last six months I have being holding back. I constantly read forum posts like...

"Why won't my car start"
"Its to cold for my car to start"
"I have no idea whats wrong"
etc...

It really puts me off getting one as I really don't know what I'm getting myself into. I'm not really that mechanically inclined. I do basic work on my car like oil, brakes etc... but when it comes to the engine and electronics outside of bolt on's then I usually pay someone to do it.

Now, if or when I get an ECU I would be paying someone to install and properly tune my car. With that said what am I really getting myself into? If its professionally done by a very reputable person what sort of daily problems might I expect?

If it's properly professionally done you shouldn't have to worry about much at all. Just remember OEM engineers spend thousands of hours on a single tune with access to all the engineering specs and computer generated models for every part of the car.

When you get a "tune", you're asking some guy on a dyno to replicate this in ~40-80 hours. With nothing but the cars reaction and the dyno readouts. It's a hard task.

But if they're good, it should be pretty good when you leave. If it's cold when you have it tuned, it might not be perfect when it's warm, and vise versa.

What year car do you have and what are your plans with it?

I might suggest wiring in an innovate mtxl or aem uego before you do anything, just to see how the car reacts during cruise, accel, startup, etc. that's a great way to start learning.

And most importantly where are you?

Hey Curly, I own a 2004 MSM, I pretty much have a full Little Enchilada with the odd part that deviates from FlyinMiata.

I have tried the O2 Signal Modifier and its great for daily driving. But if I'm ever on it I'm running extremely lean. If I roll into acceleration at a lower RPM the O2 Signal Modifier works fantastic, but if I'm coasting at 4000RPM and put my foot down I hit 18/1 on my wideband at 9PSI for a second or so before it jumps to 10/1. This is extremely worrying and forcing my hand to move to a custom ECU as I'm worried about engine damage over time, right now I feel if I drive my car aggressively I'm always worrying looking at my AFR which is annoying.

With that said I like a reliable and solid stress free car, I daily my MSM and don't track or autocross. Its just a car I enjoy driving spiritedly and have a bit of fun with anyone who rolls up alongside me.

Its annoying really as I love my car, but the modifications have pushed it to the edge forcing my hand to get a custom ECU. I wish Miata's would have some kind of COBB solution as its a lot less intimidating as a none wrencher.

I live in South California so also have to worry about SMOG. My next SMOG is in Janunary next year and my car is already not legal. But I'm pretty confident it will pass the sniffer test and I have some old CARB stickers from old AEM parts which I think might be able to blag me through my aftermarket intake. The Downpipe has a CAT and FlyinMiata says it will pass the sniffer test for around 20,000 miles so I'm good there also. Obviously if I go custom ECU that will change.

That's pretty much my situation and dilemma. One side of me is just like... fuck it... get the ECU and see how it goes. I won't know until I try and if it goes badly I just try to move on and take the hit to my bank account. The other side of me is even tempted to sell my MSM and move to a platform thats a little more intune with me as a person.

I really don't know, but right now I feel I can't drive my car aggressively because I don't have the tune and the O2 Signal Modifier isn't what I had hoped it would be.

FlyinMiata Intake System
Fab9 Intercooler
MagnaFlow Downpipe
OEM Mid Pipe
Racing Beat Muffler

(Want to move to a MagnaFlow CAT back to make it a complete MaganaFlow exhaust)

the downpipe won't pass visual. but if they overlook that, it should pass.

my 04 MSM worked perfectly with MS3, and if you do it right, install/uninstall takes all of 10-15 minutes.

really, it's not that hard to switch back and forth for smog on a car like yours. and if you get someone that knows what they're doing to tune your car, the difference will be mind blowing.

when I bought my 04 MSM I bought a MS3-Pro for it before I even bought the car. that's how much I feel the car needs it. and the difference was shocking (in a good way)

PS: I'm in Sacramento, otherwise I'd offer to install/tune for you like I've done for so many others.

I think its just about finding the right place, I generally avoid SMOG stations that look official. I always try and find one that is like a little garage on the side of the road with a DYNO that looks like it hasn't being used in decades. Last time I got SMOG the guy tried to bend down to look under the car and said "Holy shit this car is low" then gave up. The last time I got my RAV4 done they didn't do any tests at all, just plugged into the ECU and said I was done. So fingers crossed next time around!

But anyway, hearing you guys speak positively of owning a Miata with a custom ECU is a little better. I'm getting the impression the majority of people who have problems are potentially people who do it without knowing what the hell they are doing?

I'm fairly confident I will be able to figure out issue if or when I get any... I will get a quote from the local Miata guy and see how much its going to set me back. I won't know really until I try so lets see how the whole experience goes.

There's no more dyno for cars newer than '00 iirc
They just inspect visual (and like you said, most too lazy to inspect underbelly), plug in, and you're done.