Interesting. The exhaust doesn't smell super rich, but worth a shot. I would figure if one cylinder had fuel, but wasn't igniting that exhaust runner would be cool(er) compared to the adjacent ones.

I'll do some reading on Tunerstudio test-modes. Didn't realize they were in there.

Sooooo. Tested ignition today. Methodology was as follows :

Start engine, individually unplug each coil (since I'm running cop it was very easy) and notice results. Each coil when unplugged made engine studder and bog the same. Well, that means they're all firing. Crap.

I pulled each plug and did an ignition test through tunerstudio. Same. They all sparked, and seemed to operate normally.

I'll buy new plugs all the same and try it.

So I have fuel. I have spark....

I guess next step is to do a compression test (keep forgetting my tester at work). Will report back once I get the results of that. :hatecat:

Post tune and log

I just went through a similar situation. It turned out that one of my injectors wasn't firing.
If anything its realllllllly easy to test the injectors individually in tuner studio.
The fact that it will idle at an afr nearing 20:1 means that there's likely pure air being pumped into your exhaust.

Plugs all gapped the same? Similar appearance at the business end (i.e. no buildup, wetness, etc.)?

It is possible to have a slight misfire that will get worse (become a dead cylinder from a weak but still firing cylinder) once you remove fuel or spark.

Sorry guys, been busy as hell with work/life. Literally was JUST able to come back and check this and do some diagnosing today after work.

Ok so. Things I've done 2.0 :

-New-to-me Injector harness (off eBay, Tested each pin for continuity and checked all connection points for loose or frayed wires. Re-loomed.)
-Dedicated EV14 injector clips on harness, no more adapters.
-New (fresh out of vacuum bag) ID1000s.
-Brand new spark plugs. Tried both resistor and resistorless. (old plugs had good color and gap)
-Brand new Denso Toyota COPs (These are pricey!)
-Checked ignition harness for continuity on all pins.
-Un-clipped and re-clipped EVERY wire connector in the engine bay and even the main connectors on my Megasquirt.

STILL THE SAME F***ING PROBLEM :hatecat:

Keep forgetting to bring home compression tester... seriously this has been on my "list o stuff to do today" for the past two weeks. I even set alarms and somehow still can't get my act together. So no compression data

Wondering if my Megasquirt is flaky or on the way out. I bought one of those CAN O2 modules from Reverant and could never get it to work. Even got one warrantied by Andrew at Trackspeed and it still didn't work leading me to believe that the canbus on my megasquirt is faulty. DIY Autotune pretty much concluded the same thing.

I'm lost. Sad.. Angry that Summer is slipping away with zero miata miles.

Attached tune and log of startup for @aidandj to peep. He'll probably say I accidentally checked some box which makes my car retarded.

So am I understanding this right. It idles perfectly, but is very lean? How does it run, have you driven it?

Does it get better when CLTs go above 140 still?

Idles solid at 1100 rpm (target), lean as hell. Sounds like a Subaru, for sure sounds way different than normal. Really like it's misfiring.

The day it first happened engine was warm and at operating temperature. Had to limp it home. Still the same condition. Since then I haven't allowed it to run more a few seconds, so I don't have any data points above 140 degrees.

Next few weeks I may have time to check timing again and do a compression test. On the old worn out motor it still Idled and ran fine despite terrible low compression, so unless this motor has a hole in the piston, it should still idle fine methinks.

Sequential ignition or injection?

Neither. Batch for lyfe. Aka poverty MS2, and no real desire to fuck with wiring.

Turns out when your downpipe cracks before the o2 sensor three things happen :

1) It will give you a lean condition that you will chase all over the place :hatecat:
2) It will eventually break in half :hatecat:
3) you spool like crazy and make very loud turbo noises and exhaust pops :likecat:

I feel retarded. :facepalm:

Ah shit, but at least you found it.

Ah man, I never considered a air leak pre-O2 sensor. Shitty the DP crack and broke, what are the next steps?

Was it your Absurdflow DP that cracked?

Yes. Tim is going to fix it for me. Just need to yank it out and send it his way. I think he plans on gusseting the welds like some of his other DP designs.

I am exite. I was getting rather discouraged at it giving me grief. Turns out it was a simple problem, and this gives me some time withe the car on jackstands to wrap up a few other projects (meth injection namely :likecat:) and fix a few oil leaks (because I can't seem to build a motor that doesn't leak... :hatecat:)

Up To Next Season Potato Plans are as follows :
-Remove DP and send it to Tim to fix. :likecat:
-Meth injection wired and plummed
- Finish tuning at around 14-15 psi MBC
- Enjoy car for remainder of sunny season
-Winter is coming
- Pull suspension for rebuild/ Feal 441 / Xidas ???
- Probably throw down on delrin bushings from SAdFAb.
- Install back half of BBK + redo u-joint in driveshaft. Still want a 3.9 or 3.63 rear end.
- Maybe seats/Harnesses? I'm fucking tall (6'4.5") and need to figure out how to get close to passing broomstick.
- MS3 + sequential spark and injection (long overdue on this one)
- Turn up boost?
- Not die
- Suggestions ???

Right there is your problem....

https://cimg6.ibsrv.net/gimg/www.mia...71985100d9.jpg

https://cimg7.ibsrv.net/gimg/www.mia...b3fd47f7aa.jpg

Triple post FTW. :hatecat:

Got word back from Tim that my Downhipe is fixed and shipped back.

To celebrate I ordered Xidas. :likecat: :party:

That is all.

Le Update :

Tim mailed back my Downpipe. She's a beauty. He gusseted all the welds so no more cracking, AND to top it all off the gussets are laser'd with his logo. :likecat:

Should hopefully be making positive manifold pressure by next week sometime!! :party:
https://cimg7.ibsrv.net/gimg/www.mia...da7346970e.jpg

https://cimg8.ibsrv.net/gimg/www.mia...9d2e815181.jpg

https://cimg9.ibsrv.net/gimg/www.mia...6070e26c18.jpg

Also... one of these showed up... Now FedEx needs to find the remaining 3 :hatecat:
245-40r15 VR-1s on the way. Hope I can make them fit, if not flares.

https://cimg7.ibsrv.net/gimg/www.mia...a2ff0ed036.jpg