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-   MEGAsquirt (https://www.miataturbo.net/megasquirt-18/)
-   -   cylinders 2 and 4 running rich :confused: (https://www.miataturbo.net/megasquirt-18/cylinders-2-4-running-rich-confused-21944/)

Matt Cramer 06-06-2008 08:59 AM

Overboost protection looks like it's at 220 kPa to me.

I have PM'ed Kotomile about this - we will look into this one a bit more closely.

Braineack 06-06-2008 09:09 AM


Originally Posted by Matt Cramer (Post 267480)
Overboost protection looks like it's at 220 kPa to me.


might be my settings, i have things is PSI where available..i had errors, so that was probably a bad conversion.

FoundSoul 06-06-2008 10:43 AM

He's using RPM based AE, so don't turn that off.

He's NOT using EGO correction IIRC so it's disabled and the table isn't configured.

ASE is OK to have at 160, most cars still need some. It will decay and cut out completely over 30 seconds in the current config.

Yep, looks lean at idle. Yep no advance at idle. That stuff's changed since it was here.

Overboost appears to be at 220 kpa, he's boosting 14-15psi so that should be fine.


My suspicion was a short, or a problem with the injector driver. It was fine when it was here on the dyno-- but something's not right now... are you still in town man?

kotomile 06-06-2008 09:12 PM

I admit I messed with the lower left cells in the fuel table and timing table since the dyno session, trying to get the car to idle right and not idle pig-rich. Of course, that didn't work, I replied to Matt's PM and I'm hoping we can work something out that doesn't involve too much downtime (for several reasons).

'Course, the msqs from the dyno are still saved, so I'll simply go back to them once the problem's solved.

Jerry - I'm in Augusta. If I could get some time next week, it might be beneficial to drive over (in the OTM.. 16 mpg in the Miata) if the MS can be diagnosed or exchanged in one day.

kotomile 06-06-2008 09:16 PM


Originally Posted by AbeFM (Post 267236)
Oh, it doesn't happen for a while?

If you run it for a while, 20 min or something, shut it off then immediately start it again, how is it?

I wonder if it's electronics heating up....

The process I described (stoich, then lean, then rich) takes all of 10 seconds. If I shut it off when hot and restart it goes immediately back to idling rich.


Originally Posted by Braineack (Post 267237)
post a log too. needs more log.

The two in the first post are pretty typical presently.

AbeFM 06-09-2008 07:45 PM

I'd load the old msq, just to make SURE it's all ok. Might even reflash the code, though I doubt that's the issue.

Can you open the case? See how things look? You might run the car for a bit (or on the stim) firing everything, and see if anything gets hot. Touch the chips, if you burn your finger, something's wrong. :-)

kotomile 06-10-2008 05:20 AM

It's already on it's way to Jerry and Matt :)

kotomile 06-11-2008 06:10 PM

Matt ran it through the tests, the MS is working fine...

So now, I suppose it's time to de-loom my wiring harness and look for shorts. :vash:

And just because it can't hurt, I'll try reflashing the firmware too.

AbeFM 06-11-2008 06:19 PM

If they tested the MS and it's fine, DON'T CHANGE IT. :-)

Get to the wiring.

BTW, in the test, did they run real coils, to see if it gets hot, or just run it on a jimstim? No current draw there, so it would test fine but not show a near-death componant.

kotomile 06-11-2008 06:22 PM

I'm not sure, that's more a question for Matt Cramer.

Matt Cramer 06-12-2008 07:52 AM

We ran it on a bench testing device with live injectors first, then on our own turbo Miata.

AbeFM 06-12-2008 01:16 PM

Does about narrow it down, doesn't it?

Er, there's no low ohm injectors on his car, is there?

Anyway, wiring seems the reasonable place to look.

kotomile 06-12-2008 02:19 PM

Driveway is covered in 15 year-old coiled electrical tape :)

no leads yet, but dammit I'm gonna find this short.

kotomile 06-12-2008 02:24 PM

No low-ohm injectors here Abe! I run red-top 460s.

kotomile 06-12-2008 09:33 PM

I must've found it, all I really found was a couple shoddily taped up connections from my bipes uninstall. No more Subie idle, and AFRs are around 13.3-13.5 at idle. Cool!

Matt Cramer 06-13-2008 08:08 AM

Congratulations! Faulty wiring will get you every time.

kotomile 06-13-2008 07:39 PM

I owe you and Jerry a debt of gratitude, you made room in your busy schedules to diagnose my working ECU and shipped it back without complaint.

AbeFM 06-13-2008 07:52 PM

Hey, awesome! Congrats...

kotomile 06-13-2008 08:00 PM

Thanks, I'm glad this wasn't like my last wiring issue, which took months to fix.

I'm kicking myself, however, for unwrapping all the wiring harness in the passenger side of the engine bay before thinking to look in the footwell..

..at least I got shiny newly-wrapped wiring harnesses out of the deal.

kotomile 07-23-2008 01:24 PM

Well, I thought I had this licked, silly me.

Pulled the plugs just now after running for a few days on the COPs, and the same symptoms are on the plugs, except now 2&4 look about right and 1&3 have a white looking ground strap. So same problem, but now leaner! It's not running rough like a boxer as it was before, or spewing black smoke from the tailpipe, but this is just as scary, or scarier since it's leaner. Hopefully I can get these pics up...

Could the injectors being grounded constantly like they were before have damaged them in some way? That's really all I can think of, if they were still stuck open I would certainly have the same boxer idle and black smoke (and constant >11:1 AFRs) as I had before. Should I try moving the injectors around and see if the problem follows them?


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