Graxis

I picked up an MS2 DIY (not PNP) with v3.0 mainboard for super cheap a week ago as the first step on my way to a turbo build. I've found every answer I needed as far as modding the board for my 1996 Miata, building the wiring harness, installation, etc either here or through reading the MS documentation.

Unfortunately, I've finally hit a brick wall. It's the usual: The car will start, but only if I give it gas, and only if I keep giving it gas. It runs rough (as in barely) and won't start or idle on its own at all and I thusly haven't been able to verify timing.

Relevant information: 96 Miata, bone stock 1.8. AEM X-Series AFR. GM IAT sensor from DIYAutotune. DIYBOB breakout box. I'm using Braineack's 96-97 base tune from trubokitty, with slight modifications since I'm using MS2. Mods to the board include the 2N2222/WLED fan control circuit I found here jumpered to IAC1A. Connections from the DB37 to the Nippon 76-pin in the DIYBOB are good; big thanks to Braineack's diagrams. I have spark at all four cylinders (verified with plugs out of the head). Car runs perfectly on stock ECU. I thought I was on a roll not having to make a post, but here we are. Attached is the most recent composite log.

Help is appreciated; flames are probably deserved.

UPDATE: Checked my breakout box wiring. Had injectors 1+2 and 3+4 wired together. Fixed to 1+4 and 2+3. Changed the MAP sensor settings in TS (I realized the MAP was reading 150 kPa; changing the sensor brought it to the correct ~100 kPa with the car off). Got it running relatively smoothly for a few minutes at about 1300 RPMs (which I believe is due to the advance settings not matching up between the crank and MS). I'll check on that tomorrow. I believe my problems at the moment are solved except for the constantly running fan, but that's something I just need to read up about. I'm out of the woods!

Graxis

20 hours later and I've made no progress whatsoever. The car cranks, catches with throttle, and idles around 1100 RPM while running extremely rough, like it's missing. I've been through the harness and board more times than I can count, I have spark on all four cylinders, the injectors are good, advance is correct, and idle valve has been tested. I've went through multiple threads and videos, and have gotten absolutely nowhere. The car runs extremely lean, hence the high numbers on the VE table; this was the only way I could get a steady idle long enough to try (fail) and troubleshoot. Car continues to run perfectly on stock ECU.

Logs and tune are attached.

festersays

iTrader: (3)

Disclaimer, I'm still a newb at megasquirt.. I took a look at your tune though and it seems like your engine displacement size is set up for a 1.6, and your injector size is set also to a higher then stock setting. I didn't see you mention that they were larger then stock injectors. I would take a look at that and correct it to get a good req. fuel number, then try again. I thought I saw that you chose closed loop idle also, I would recommend to turn that to open loop mode for now until you can reliably get the engine running and idling. Good luck and hopefully you can sort it out over the weekend.

Graxis

I just pulled the plugs and 1+3 are dark/almost black, and 2+4 are white. I'm going to take a wild guess and say that's where the problem lies.

Graxis

Going over the mainboard, R35 and R37 had been replaced with transistors instead of the current-limiting resistors specified in the Megamanual assembly guide. One had the legs snipped and then jumpered; the other just had two pins soldered in place. My fault for not checking more thoroughly when I was modifying the board for my car. Removed/replaced, and now we're up and running right.