Ground issue

[Romak]

Yesterday I went to start my car after washing it. It started, idled to 1000 rpm then died. I tried this a couples times before getting out the computer and plugging it in. After running tests the computer says its the AFM. I took it out opened it up and tested it but it seemed to be fine. Did some google searches and looked on the forums and found it may be the ICV. So I unplugged the ICV to eliminate it, started the car and it idled steady at 1000, figuring it was the ICV i removed it and cleaned it today. I put it all back together (ripping the end of the crankcase vent hose in the process) I scabbed the hose back on and went to start it. Started with no CEL but still idled rough 700-800 rpm approximately. It was running rough before all this occured i thought it was because i was on the last of the 87 octane i first put in and almost on the 91 i just filled it with. Ran the computer tests again and it said AFM and Knock sensor 2, shut it off unplugged the AFM and attempted to start it but again wouldn't stay running. Plugged the AFM back in and unplugged the ICV and it held steady at 1000 with strong odor from the exhaust (running rich im assuming?), ran the tests and it comes back with ICV and only the ICV, the knock sensor and AFM codes did not come up. Went for a drive, came home pulled the hood release, went to lift the hood and my alarm siren goes off. Turned it off closed the hood and did it again, same thing. I was puzzled so i closed all the doors and the hood tried to arm the system and it arms with no chirp (normally chirps when arming). Then removed the negative terminal and cleaned it, went to reconnect and the siren went off which i expected. I was unable to disarm it with the fob and it randomly stopped going off but the park lights continued flashing i then turned them off by pressing the hazard light switch twice.

So far i am convinced it is an electrical issue there are too many coincidences to be separate issues. It all started after washing my car, could i have gotten water somewhere it shouldn't be?

Any insight on this issue would be helpful.

[cooljess76]

Sounds like your ecu got wet.

[Romak]

I had read that it could also be an ecu (dme the same thing?) Can i dry it out or is it fried?

[cooljess76]

Yes same thing. IDK, try removing it, opening it up and allowing it to air dry indoors. Dry out the compartment while you're at it.

[Romak]

Removed the dme, check the compartment and the dme, both are dry and dusty. Looks like its not water. Put the car on the computer cleared all the codes and retested. This time I get 201 Lambda Regulation. Its telling me to check my spark plugs which are less than 2 weeks old, exhaust, temp sensor, injection valve, intake tract etc. Could it really be one of those things? Keeping in mind that before I disconnected the battery at all my ews system went haywire. Lifted the hood at the parts store to show the guy the crankshaft vent hose i was looking for and it went off as i leaned in to put it back on, I swear i didn't lean on the key fob. It just randomly went off with the hood open.

[jiggapoo]

I'm fighting a similar problem with my 205k mile M42 318i right now, as well. Mine is not as severe as yours, but possibly because I don't have keyless (or an alarm).

I have been getting on-and-off-again issues with a random TPS code at start-up (accompanied by knock and voltage level codes). My problem was traced to two areas: the positive "junction" or distribution point on the front right wheelwell and one of the knock sensors, itself, through which the TPS was grounded. I assume that a severe-enough ground might cause the ECU to get confused.

If you don't already have the wiring diagram (through Bentley or similar) it may be worth your while get a copy and do a trace and see what touches your alarm, to begin. Otherwise, begin tracing wires for continuity.