Why is my m50 running pig rich

[ScHpAnKy]

Confused, my m50nv is running so rich it's shooting flames...
granted, I don't have an o2 sensor but neither have my last couple cars and that was never an issue...


Cool temp sensor and sender are brand new, CPS is brand new, running 413 ECU since my 402 died. Harness checks out fine so I think it's a sensor somewhere, or DME? The only things that aren't new on the engine are the cam sensor, ICV, headgasket, and IAT... are any of those suspects?

[bimmerteck]

I don't have an o2 sensor

^ This would be my first guess.

[lolcantturn]

You need an O2 sensor dude. M50 runs like utter shit without it anyway

[slammin.e28]

Car can't make calculations. Rather than go lean (and EXPLODEEEEBOOMMM!), it protects itself and goes rich. Need dat o2 sensor. Rich > lean. It's a smart cookie.

[nando]

I don't get running a car with no O2 sensor. it's as critical to a modern EFI system as a MAF.

[ScHpAnKy]

welp, if I can the LC-1 working with this, than I suppose that'll be my next step!

thx all

[328ijunkie]

O2 Sensor. 413 ECU and a stuck injector are all prob your issues

[Nick_S]

Fuck it man. Flames are cool.

[ScHpAnKy]

O2 Sensor. 413 ECU and a stuck injector are all prob your issues

Stuck always on? I've got a shit ton of injectors I can swap in for free, but how do I figure out which one it is?

I just bought an LC-1, I understand I need to run the narrowband back to the DME for it to function as an O2 sensor and not just gauge?

Also, I have two 402 ECUs I can swap in, are they better than the 413?

Fuck it man. Flames are cool.

Hell yes! But I only want them between shifts :P

[greyis89]

My swap at it's early stages ran super rich and stumbled with a very touchy throttle. Maf sensor was the culprit for me after checking many of the things already mentioned.

[gp.plus]

Pull the plugs, that should tell you which cylinders are running rich.

[N2MYE30]

I was unaware that a 413 works on a NV.

[ScHpAnKy]

I was unaware that a 413 works on a NV.

I was unaware that the 413 didn't! :D
I know the later ones definitely don't work

[drez14]

+ 1 on stuck injector. or it could be a fuel pressure regulator problem. If your fuel system is running at a higher psi, then more fuel is shot in a given injector cycle. Pull your injector rail and jump the fuel pump relay. If you see leaking fuel then you know what and where the problem is.

I dont think its an 02 sensor problem. It wont run optimally without one, but i dont think the computer is capable of overcorrecting so much that it will consistantly shoot flames.

[greyis89]

Ok just watched the video. Dumping fuel at a fairly steady firing rate. I'm thinking fuel pressure too now. Unless you're building a funny car.