My understanding is that AFR is AIR to FUEL, which means 14.7:1 is 14.7 parts air, 1 part fuel. Meaning 10.2:1 is less air than 14.7:1.
Source: https://www.turbobygarrett.com/turbobygarrett/airfuel_ratio_tuning_rich_vs_lean
It’s entirely possible, but the exhaust smells rich to me. I can smell unburnt fuel before the cat heats up.
Probability is that they put larger injectors in there.
It doesn’t have to mean less air measured in volume, just less air per amount of fuel.
Makes much more sense. For some reason I thought the first number was fuel. Shows how much I know about tuning haha.
Anyway, that seems much more likely, have you tried messing with the injector size in the ECU yet?
I’m thinking I’ll play around with it later, but I actually found out that using the auto tune (VE Analyze) feature on Megasquirt to tune idle causes problems (per miataturbo.net), so I’m going to try manually adjust the VE tables to see if I can get somewhere.
That said, I haven’t had time to mess with the tuning since Saturday. Just been busy.
That’s what I meant, with the same volume, there would be less in 10.2 than 14.7.
I’ll be honest, this is the first car I’ve done any major mods to, so I’m still new to all this. I’ve spent more time reading about engine tuning than actually doing it.
Dude you said it was so clean that you can’t kill yourself with it, how was I supposed to take that statement any other way than literally?
I actually thought about checking a Miata forum to see if I could find your problem, but I’ve been busy or forgot when I did have time.
I’m glad you we’re able to find a promising solution.
I’ve done engine swaps with using the new engine’s ECU and wiring harness, but I haven’t done anything as far as tuning an ECU it’s self. It is something I want to learn, and I’ve considered picking up a megasquirt. If it could run a 5 cylinder with drive by wire and coil on plug I would likely have one, but from my understanding it can’t be done easily.
If you have a factory wiring harness on a car that’s popular to modify, look at diyautotune.com. They do MSPNP setups that are literally plug and play. (short of the tuning, that is)
Here’s a good resource on the overview of the Megasquirt family.
https://www.miataturbo.net/megasquirt-18/summary-megasquirt-family-newcomers-81522/
My recommendation is get the MSPNP 2 or MSPNP pro, depending on what’s available for your vehicle.
I’ll have to look at those later.
I doubt there’s any PNP for my 99 Volvo. I really handicap myself trying to modify obscure cars. I was looking at getting a Haltech ECU, but those are like 2 grand.
Someone on swedespeed did a bit of work on reverse engineering the fuel and spark maps of the T5 for MS. I’m assuming that’s the engine you’re referring to.
Your bringing back my car modding ptsd haha. Never ever does standalone installation and tuning go off without a hitch haha.
For the AEM, or any wideband for that matter, the aux out to the EMS will always need calibration. The MS guides should have a section on going in and calibrating the wideband aux in voltage levels so that your EMS logs line up with what the gauge is outputting. As far as brand, AEM is great. I bought into Innovate’s margetting and had two of theirs, such a huge pain to wire in, super finicky, overheats, takes too long to warm up etc. AEMs are awesome.
For your idle tuning, is the miata using an IACV that is well supported by the MS? If I remember correctly there was maybe better development one the two wire and three wire IACV front, and if you were running something else its not as well supported. There are also a few different algorythms to choose from for idle control. Regardless remember it could be worse. I was tuning an MS3pro around a DBW TB car, its like a dog chasing it’s tail- it will always be a little rough and RPM hunting- most people break down and find ways to bypass the DBW with some hack mods, or replace the TB all-together and plumb in a Honda IAC.
Went to install an oil filter relocation kit on the 5vz Tacoma truck, kind of botched it and instead of remedying the install I took it off. The whole time I was putting it in I was worried about reliability. Adding 4 fittings, lines, caps on sensor ports on the kit etc was adding too much Murphy’s law for a truck I flog on off road. I guess I’ll put the kit on the other car.
I’m going to go back in and figure that stuff out. I thought I would be able to just plug and play after selecting the “AEM UEGO” preset in the software, but I guess not.
I believe so. Lots of people said the stock IACV is plug and play. I’ve actually got idle running okay. Once it’s warm, idle bounces between 810 and 845ish. I just need to fine tune the PID loop on it. One thing I did notice is that the TPS seems to show foot-off-throttle being 4.6-4.7% open and WOT is 105.1%. Is that a normal situation or should I find the calibration docs for that as well?
I’ve always had a blind trust of AEM because it’s what the hot-rodders used when I was in high school.
Mid 00’s, didn’t have much money but lots of them had classic sheet metal with big blocks and EFI. Those were the days!
Its more a “best shot”, as grounding point, wiring length, electrical noise etc variation will be on every different car. Props to MS for having such a good selection list though. The worst I’ve seen is the AEM FIC piggyback, it is WAY WAY off. As much as I like AEM that piggyback had some issues that shouldn’t have made it to prime time.
Yeah TPS is like Air Fuel, have to calibrate it. There should be a menu somewhere where it has you click a button for off throttle, then again at WOT to get it’s idle value and WOT value.
Good point. I knew people were talking about grounding being important, but I didn’t realize it would be that big of a deal. I ran a grounding wire to the grounding point on the back of the head (supposed to be the best ground in the engine bay) and it seems to be stable, I just need to calibrate all this stuff.
That makes sense. I’ll have to look for it.
I’m much less discouraged now. I think I’m going to get on this later today.
I’m probablly going to skip on the idea of a cheap downsized diesel car,
as a dailly driver.
The reason that its pretty hard to find a reliable one that has reasonable millage on the and not breaking the bank.
Now i’m probablly going for something that is rock sollid and reliable that runs on patrol.
Maybe something JDM style 
Hmmm, Subaru is probably my recommendation. If only because they’re good on gas, fun, reliable and built out of legos, so if you ever need to replace something, you can find a replacement easy at the wreckers.
S10 auto to manual swap update.
I’ve been slowly working on my S10. I’ve got all the parts I think need off the Blazer except the clutch master cylinder. I’m getting ready to pull the automatic out. I Drained the fluids, dropped the drive shafts, unplugged the O2 sensors, and sprayed the exhaust bolts with penetrant.
I ended up getting a little better picture before I started.
I will definitelly look into Subaru’s, they are pretty reliable thats for sure.
But i might also look into something like Nissan or Honda.
I’m not personally a fan of Nissan or Honda, I just don’t like the vibe I get when I drive them.
That said, they’re definitely not bad options. I just don’t have much good to say about them.
You’re not a fan of the Z line? I loved my 300ZX.
@MisteryAngel don’t forget about Mazda. See if you can find something with their 1.8 - 2.5L v6.
