So, it's been a busy month and I haven't had a lot of time to work on the Stang until this week. I have ended up relocating my PCV valve to the driver side valve cover, with the breather hose in the same location as stock (between filler tube and intake elbow).
Today I finally got around to starting it again, after relocating the PCV, carefully checking the adjustment of the rockers, cleaning out the intake thoroughly, draining the oil out of the vacuum system (yikes), cleaning the intake, purging the oil from the cylinders, and replacing all the plugs which had fouled up.
Lo and behold, today it started up pretty well, albeit with a couple of hiccups.
- I have a vacuum leak that I'm going to fix tomorrow (which explains the idle surging and high idle speed)
- The MegaSquirt had overrun fuel cut turned on (which I didn't know about until viewing datalogs later), which was causing the computer to intermittently command zero pulsewidth to the injectors, causing a lean/misfire condition (this explains most of my problems including why it's running a bit rough, not to mention that I haven't dialed in the VE tables yet).
- The timing table was set way too low at the higher load levels near the lower RPM region, because I pulled a few degrees here and there before I started the car to make sure it wouldn't knock. I forgot to bump all the cells up to at least 10 degrees before starting it.
- I went with the recommendation that came along with my cam and set the lifter preload to 1/8 turn past zero lash. Comp Cams seems to recommend 0-1/8 turn of preload in general, but I think the valvetrain is a bit noisy, so I think I may tighten them down to 1/3-1/2 turn instead.
Tomorrow I'll be working on getting it to idle OK without IAC, and then I'll be working on getting the IAC valve to keep it rock steady.
Here's a video of it while I was trying to diagnose the roughness and the surging in realtime, and a bit of revving the engine to see if it breaks up at higher RPM toward the end.
My camera has a really crappy microphone, and the recording has a lot of tinny distortion in it. Sorry about that.
EDIT: Oh, and notice - NO SMOKE
EDIT 2: Datalog showing the the accel enrichment / overrun fuel cut is indeed what's causing my erratic fueling. It correlates perfectly.