So yeah, you guys know my luck with cars. There was a short thread in the lounge talking about it, but here's the whole story.
You know how sometimes on manual cars if they're started wrong, they shake violently forward and backwards? Well yesterday I was driving along yesterday going about 30, and it randomly started doing that. I thought maybe it didn't get into gear correctly or something, so I shifted and it smoothed out. Weird.
About 500 feet later I got to a stop sign. As soon as I stopped, I stalled. Weird. I started the car back up, and the revs jumped and struggled to stay up it looked like, but eventually they dropped too low and I stalled again. Weird. I turned the car on again, and the RPMs dropped straight to zero and stalled. Weird. I then tried to start the car again, and it wouldn't turn over. I could hear it trying with the "reur reur reur reur reur" sound, but it wouldn't start.
Luckily I have some amazing friends who are pretty savvy with a wrench (since I'm not). I called them up, and half an hour later there was a line of BMWs up and down my street (yes, I ended up having to buy pizza for everyone who came out, hah).
Rob was the most knowledgeable (as usual) and ended up going down the list of things to scratch off. We were first thinking maybe it was a vacuum leak and the engine was starving, and each additional time I tried it, the hose got more loose or something. No visible hoses were detatched or loose. Airflow was fine, and even removed the intake to allow direct air suction, to no avail.
We then thought maybe it was the fuel, so took off the backseat and listened for the fuel pump clicking on when the key was moved to the ON position. It clicked on, and upon removing the cover in the engine, we think could hear fuel moving through the fuel rail. Okay, another one off the list.
We tried disconnecting a few things, and forgot we left the TPS (throttle position sensor) off when we tried starting the car, so that threw a CEL that confused us for a while. But we soon realized our mistake and went on to the next thing.
The next CEL it threw (checked via the pedal trick) was 1281, something about the DME's memory retention. We tried unplugging the ECU (battery first of course) for 15 minutes to let it reset. We plugged it back in, and the car started!.... for about 4 seconds. It did the same RPM struggle, and stalled again. Start again, stall. Tried to start again, and it wouldn't turn over. Same thing as last time.
Seems like a ECU problem. No signs of wetness, and it hasn't really been in the rain recently, so I'm ruling out the older e36 problem of flooding because of the drain plug. We tried plugging the ECU into Rob's 93 325i (also a DME 413), and his car did the exact same thing, the engine wouldn't turn over.
I thought that meant it was the ECU for sure, but alas wrong again. I spoke with a local BMW tuning shop (strictly german) and they explained the two types of ECUs in 1995 m3's... burgundy label vs clear label. I'm pretty sure the label on my DME was white (if I remember right), and thus clear label, meaning it has the early stages of EWS, and without the microchip setup, it wouldn't start Rob's car anyway, regardless of if it was good or bad. So currently I don't know if my DME is good or bad.
I checked the thread this morning in the lounge, and Rob mentioned he was onto an idea regarding the HFM/MAF. He's still sleeping now though, so I don't know what he was talking about.
Anyway, right now my car isn't drivable. Does anyone have any ideas or suggestions? What would be the next step for troubleshooting it? Thanks!
Cliffnotes: Car was driving fine and randomly started stalling. Then wouldn't crank at all (engine trying, but couldn't turn over). Ended up resetting the ECU, and it stalled and did the same thing. Throwing CEL 1281. Need to get car drivable, so please read the whole thing above, haha.