(VIDEO) 327i hunting and running rich at idle

[nando]

the heating circuit is always on. But maybe it's not working. try swapping the relay with the one for the fuel pump. also try running with the O2 sensor unplugged.

[rcfanatic]

The wideband controller provides power to the heating circuit, so relay wouldn't be the cause in this case.

I'll try unplugging the O2 and report back

[nando]

so you're using a wideband to send data to the ECU? are you certain the narrowband output is hooked up properly and calibrated? how about grounds? where is the wideband getting power?

[rcfanatic]

The documentation states that no calibration is required for the O2 sensor. However, there is a narrowband switch point that I can adjust.

"The default Lambda Switch Point is “1 Lambda”, at Lambda =1 the Simulated Narrowband Voltage is 0.45[v]. When your ECU sees 0.45[v] it will believe that the engine is running stoich. By shifting the switch point to below 1 Lambda, your engine will run richer at light engine loads. By shifting the switch point above 1 lambda, your engine will run leaner at light engine loads."

So maybe I'll try raising the switch point.

Ground is where the valve cover grounds to the battery shelf. I tapped into a window switch for the 12v

[nando]

LC-1?

I just wonder if the second output is set to wideband instead of narrowband.

[rcfanatic]

SLC Pure Plus

It has a dedicated narrowband output and I don't see a way to switch it to wideband. I don't believe that option is available.

[nando]

allright, that makes enough sense.

I'd try running it open loop first (be sure to reset the ECU by unplugging the battery) before mucking with any settings of the wideband.

[e30trooper]

what exhaust are you using , the ETA , or I ? , the eta o2 sensor is located next to the CAT, the I is located right below the headers ( on the down pipe ) could be an Issue. Sorry but I dont feel like reading 38 post lol

[nando]

I don't think that makes much of any difference.

[rcfanatic]

I'm starting to think that my AFM may be the problem. I'm guessing the spring has lost some of its stiffness and it's reading a higher value for air then it should be.

I've read several threads about adjusting it, and apparently there is a screw you can use to let in more air and lean out the mixture.

Where is this located?

[rcfanatic]

Just filled up again yesterday.. getting about 10 mpg right now.

Does anyone know how to tighten up the afm (spring) so it won't read so high?

I'm want to convert to the miller MAF after I save up some more funds, so I don't want to pay for a remanned AFM if I'm not going to keep it very long

[rcfanatic]

Bump..

Would appreciate some help. What do I tighten in order to make the AFM spring stiffer? I've read in some other threads that it is possible, but with no explanation of how to do it.

Driving to orlando on Friday and don't want it to cost me a fortune at 10-15 mpg

[call me jack]

google m20 afm adjustment. i found this when i typed bmw afm adjustment

http://forums.roadfly.com/forums/bmw/bmw-3-series-e30/3147035-1.html

[rcfanatic]

OK, so I bit the bullet and just bought a remanned AFM and HOLY SHIT did that do the trick. I've had this car since 2004 and never has it run so well.

No more hunting at all; sits dead steady at 750 rpm during idle. The idle speed doesn't drop when you first touch the throttle so no more "blipping" before taking off. Couldn't be happier except now the wideband shows the AFR to be really high.

I found a few minor vacuum leaks when I did the smoke test a couple weeks ago. I'm wondering though if the lean condition is being caused more by the low fuel pressure than vacuum leaks. Thoughts?

[rcfanatic]

I should also mention that at cruise the AFR is in the 16's and at WOT it's in the 13's