Progress. It runs! It drives!...But....Yes there had to be a but didn't there?
OK, so as I said above it runs. I removed the exhaust and it ran the best it's run in over a year. I could actually drive it around the subdivision without slipping the clutch or a bucking bronco impression. When I got back I figured I'd try it with the MAF unplugged again per a suggestion from the SaabRally guys. Apparantly with the air meter unplugged the car should resort the fuel injection to a sort of limp mode, where it injects fuel based only on RPM and throttle position. This can be helpful for diagnosing mechanical problems (rather than fuel injection sensor problems), since a plugged cat will make it misfire badly under load either way.
It will run badly, but if it will run under some load and at higher RPM's with the Air meter unplugged that points you to a sensor issue. If it does the same thing it could be mechanical.
So I get out to unplug the air meter. Guess what? it was still unplugged from the night before. Plug it back in and it won’t run for E36 M3 again again.
So if you're following it would sort of run, but badly with the exhaust on and the MAF plugged in, but if you unplugged the MAF it would stall. Remove the exhaust and it's running 'well' when the MAF is unplugged, but stalls again when it's plugged in.
Right now I'm thinking it's a MAF issue. The plastic cover fell off when I touched it, so some foreign material could have got into it over the last couple of years. The exhaust is in mint condition, everything looks almost new, other than the studs that sheared when I separated the downpipe from the elbow the other night, every fastener and slip joint came undone with ease. I've never had an easier time.
So, i guess I'm looking for another air meter to try. Anyone got one for sale or return? Also since there doesn't seem to be a blockage in the exhaust I guess the seals on the turbo are gone from the gunk that was coming out of the flange in the video the other day. Si I suppose I need a $50 e-bay T3 rebuild kit then put the whole thing back together. I do have a spare, but unknown turbo I could put on.
Driving it. https://www.youtube.com/watch?v=AYqF9Bu0NNA
Pulling in https://www.youtube.com/watch?v=Wu71TZ4sca8
Cat is perfect
Pretty much mint exhaust
Shopping list:
Air meter
T3 rebuild kit
Sundry turbo and exhaust manifold gaskets
High temp paint
Thoughts?
P.S. Honestly I'm not a total mechanical ignoramuses. I've built engines, done engine swaps, fitted LSD's to FWD Trans, built one car from two etc. etc. This things is just killing me