Street Tune Review
 

Hi All - I was hoping to post a recent street tune I (pakid for) received and get feedback on it. I have seen you guys absolutely destroy some posted here so I'm curious how this one stacks up. It cost quite a bit and I'm loathe to go back to the guy to pay him more. He was nice and super helpful and short of these issues I could definitely recommend him but expensive af and I'm honestly trying to understand what I'm looking at. As for the issues I'm having a few things:

1. Many times when driving about for a while, I will clutch in for a stop/red light and the car will die. Once this starts happening it happens for a 5 to 10 minute window and then seems to stop.
2. From time to time I will get lots of cracking popping when shifting while driving >90% TPS. I'm more concerned about possible engine health issues as a result rather than the noise itself.
3. Car idles super rich according to my afr at cold start and then once warm and then sitting for a while will weirdly lean itself out to like 17+ afr
4. I have a fairly small exhaust leak at the downpipe to exhaust connection (about a foot and a half after the wideband bung on the dp). The vband flanges are very tight in this area so getting it to fit perfectly has been an issue I haven't been able to fix quite yet.

As for the car, its a '02 6 speed w/ a borgwarner 6258 intercooled and running a 7psi waste gate, 900cc flow force injectors

Upon first inspection of the VE table, it looks like your dead time may be too low:
https://www.miataturbo.net/attachmen...1&d=1709407451
https://www.miataturbo.net/attachmen...1&d=1709407451
(https://support.haltech.com/portal/e...ctor-dead-time)

As far as situational issues like the car dying at the light, I think some datalogs would help find the issue. Weird AFRs at idle could be fixed by using idle VE.

Also, the initial values table should have been tuned if you're going to use initial values:
https://www.miataturbo.net/attachmen...1&d=1709408008

You should provide a log of you driving the car and having the issues you mention, but it seems the biggest issue are your deadtimes. As @eviking said, weird VE at idle is usually deadtimes. There is also cylinder trims enabled with very varied numbers that I doubt are injector flowrate differences? Do you know the reason for that? What injectors are you using?

What wideband are you using, and how is it connected to the car? Your exhaust leak may or may not be causing skewed Lambda readings. You should fix that to be safe.

Idle control settings don't seem finished.

Knock sensor isn't configured.

There are a lot of settings that are sound in that tune, others need tweaking.

The pops could be caused by the lack of overrun fuel cut and that exhaust leak combined. Shouldn't cause any damage unless they are explosions like an anti-lag system.

Hi see attached for logs. I tried to review them myself and I've watched videos on how, but honestly I'm still a bit confused as it is overwhelming amount of information for someone who's never seen this stuff before.

TO answer questions:

1. Wideband is an AEM 30-4110. The tables provided by AEM don't work exactly for properly AFR as the MS3 reads about .3 leaner everywhere until the car is right around 15 and then it reads less than .1 AFR too lean.
2. Idle control unfiniedh - Probably, I've only played a little b/c I'm not sure I'm making it better.
3. Thanks for the update on the pops, glad it's not a major issue.
4. The exhaust leak is at the vband beyond the downpipe and at idle is quite small. I'm going to take it to an exhaust shop locally next week b/c I've tried everything I can think of and the flanges are matched up perfectly but air still comes out after the car warms up.
5. Injectors are flow force 900s which were recommended by the tuner after the 1000s Densos didn't seem to work well initially. I got them so large with the idea of running E85 eventually. As for dead times, if I change those, does that essentially supply more fuel with no other changes and thus I'll be a bit richer?
6. I remember the tuner actually telling me he thought I had a vacuum leak during the tune on the intake side, but I doused the entire engine bay (joking) in starter fluid and we found nothing. Maybe this had something to do with issues?

I found that haltech article on dead times and in their FAQ they only seem to indicate fixing the dead time will just make the VE table look more normal. SInce I'm not really prepared to re-tune my entire VE table, should I just leave well enough alone?

_______________________

Q: My VE table looks weird but the engine runs fine, is the cause my Dead Time table?

A: Yes, most likely. Good work picking up on that!

Q: My AFRs are a little unstable at extremely light load and tuning is very difficult, is it the Dead Time table?

A: Most likely not, it is more that you are likely running into Low Pulse Width issues where the injector does not completely open before it is commanded to close, and that is a topic for another day.

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Quick last question for this post. All things being done properly, should I expect my car to maintain the same AFR (with maybe .1 to .2 variance) when idling after completely warmed up? As it sits now, it will usually do this for quite a while and then weirdly lean itself out and take some driving or 'throttling' to get the AFR to return to normal.

If your gauge is reading different than TS when the laptop is plugged in, I'd make sure you have the AEM output calibrated correctly.
With the AEM 30-4110 specifically, it looks like you want the gauge set to position P0, with a "Custon Linear WB" setting in TS using two points, something like (0.5V,11AFR) and (4V,18AFR) according to the cal table in the user manual.
(https://documents.aemelectronics.com...uego_gauge.pdf)

Changing your dead times could affect the tune by a decent amount, according to FF900 injector data on the website you are currently off by about 0.2ms at idle, or 10% of fuel. If you want a consistent idle dead times are important.
https://www.miataturbo.net/attachmen...1&d=1709497359 https://www.miataturbo.net/attachmen...1&d=1709497672

Under load the difference between commanded PW and real PW is a bit smaller, on the order of about 7% of the total fuel. Still enough to put you off by a whole AFR number, though.

In response to your last question, with a good tune a couple points of AFR variance from one moment to the next in idle is certainly achievable.
The main factors here will be closed loop idle control PID, which you currently have set to "Basic," and EGO PID, which you currently have set to "Simple" and set to only correct above 1300RPM, completely excluding idle.
Making certain that you don't have the possible vacuum leak you mentioned would be a good start.

WAIT the very first thing you should have done before tuning and for sure now is the leak on the downpipe. That can entirely thorw off the 02 reading. Any air being added in will make it appear leaner than you might be.

Thanks so much for all the info. I'll try that WB setup you mentioned. I must be blind, but I don't see .5 = 11AFR and 4 = 18AFR in the table in the manual you linked. I did use that manual originally to set it up and when I told the tuner the AFRs were off, he set it to one of the presets and then just asked me how far off the gauge is versus at the MS3 so he could adjust for that in the tune. I'll mess with the dead times as well.

EDIT: I'm an idiot and see that I was using the wrong table entirely. Thanks for pointing that out.

The leak is between the downpipe and the rest of the exhaust that is 18 to 24 inches after where the wb is installed. I'll see what I can do to get it back to the exhaust shop I used b/c I have messed with it multiple times and still can't seem to get it right.

Hey Sorry meant to ask you, I can't seem to disable the fuel trims. I've googled and cant find anything there either. I'm guessing this wasn't setup on purpose as I never saw the tuner mess with these and it is left over from the base map from DIYAutotune I started with. Do you know where in UI to disable them?

EDIT, literally the moment I posted I found it. It's under Engine and Sequential Settings (for future searchers).