Engine running rich, code 1264 and fuse 9 blown help

[jwest11]

Replaced my after market exhaust with my stock exhaust and new o2 sensor. For my old exhaust, i extended the harness side of the o2 sensor which I thought I did correctly but must not have. Car has been running very rich since and I thought the stock exhaust would help... nope. Upon first start up my check engine light finally went away until I drove and the engine died and restarted immediately with the check engine light now on. Did a stomp test and got code 1246, and found fuse 9 to be blown. I assume these two are related but I'm not sure where to go now. I attempted to reset the DME but never saw "PPPP" appear on the OBC like I was told it would. Then moved onto the O2 harness to unextend it and make it normal again, I'm hoping this fixes my problem but now I'm waiting for the new pins to come in from BMW, I have 3 different sizes coming because I don't know which I need, the part numbers are 61131376191, 61131376193, 61131376195. A few more questions just out of curiosity, does the O2 sensor from an e34 fit? Looking at the photo from this link it looks to have the same connector, and an OEM extension would be nice when I decide to get new long tube headers. How bad is it for a new O2 sensor to be in the car and after one drive its black/darker, really hoping I didn't just ruin a brand new one. Thank you for the help!

[cheffy30]

Alternator? giving a charge? 9 is fuel delivery system sent from hell using tapatalk

[jwest11]

Alternator? giving a charge? 9 is fuel delivery system sent from hell using tapatalk

I'm pretty sure my alternator is good. I guess that would make sense that when fuse 9 blows the engine cuts power for a split second, right?

[cheffy30]

check the output on alternator. change fuse 9 same result? Rev it to red line.... get it on the highway and stand on the pedal. sent from hell using tapatalk

[sert57]

you sure you're reading the code right? I can't find 1246 anywhere.

it should run okish if you disconnect the O2 sensor, so try that and see what it does. I know that the wires for the O2 harness are a special metal, so it could be that the extension is messing with that.

I don't think the motronic is that sensitive to exhaust setup, so if disconnecting the O2 doesn't help much its probably something else.

[jwest11]

you sure you're reading the code right? I can't find 1246 anywhere.

it should run okish if you disconnect the O2 sensor, so try that and see what it does. I know that the wires for the O2 harness are a special metal, so it could be that the extension is messing with that.

I don't think the motronic is that sensitive to exhaust setup, so if disconnecting the O2 doesn't help much its probably something else.

Yeah, the code was correct. I rewired the harness side of the 02 sensor (took away the extension) after putting the stock exhaust back on and it runs much better. I reset the DME, replaced fuse 9 and no more CEL! I am having other problems now that never occurred with my old exhaust which makes me think they are related but Idk why.

[jwest11]

you sure you're reading the code right? I can't find 1246 anywhere.

it should run okish if you disconnect the O2 sensor, so try that and see what it does. I know that the wires for the O2 harness are a special metal, so it could be that the extension is messing with that.

I don't think the motronic is that sensitive to exhaust setup, so if disconnecting the O2 doesn't help much its probably something else.

Meant to type 1264, my bad lol