PLEASE OH PLEASE HELP. 540i/6 NO POWER

[Nicolas H]

Hi all, New to the forums, as well as BMW's. I just picked up a 2002 (2001 build year) 540i/6 M sport. Its got 157k on it. Everything seemed to be in working order but maybe not. Couple days ago I was attempting to repack my cv joint (driveshaft to diff) with grease. I dropped the exhaust, and pulled the o2 sensors out and i accidentally let the a/c drain line drip on to one of the o2 sensors but i pulled it out of the way and then proceeded with my work. Half way through I realized I didn't have enough grease, so I drove the car (open headers & o2's dangling) to my local advanced auto parts (7 miles away) and got some grease. Leaving the facility, I floored it, all was good until the top of 1st going into second. The car sputter in second and then died. I turned it back on, and once again it died. I coasted into a parking lot, and turned it back on... CEL popped up. OK im thinking no biggie, its obviously freaking out bc the o2's are disconnected from piping?? So i drove home, and it didnt stall anymore. got home, finished up my driveshaft.. (didnt fix it btw, still makes a ting ting ting noise) and I put my exhaust back on, as well as the o2 sensors. CEL is still on.. OK so I figure maybe it just needs a code cleared. So i go to advanced, and get the code cleared. The car gives me the code P0102, Low maf input? Maybe those are related bc my o2 sensors dictate fuel trim? So I clear code.. start the car. No code. turn it off and back on. Code is back. Great. Been driving now for a couple days with the light on. Definitely a decrease in power. Not a lot, but its still pretty noticeable. ok So i go to the junk yard and pull a used maf off of a 2001 740li (matching numbers on the maf) and I put it on the car. Nothing seems to have changed.. So i pull out on the main road and floor it, and experienced a HUGEEEEE power loss. Literally feels like the car is restraining itself. So I back off. hm.. ok so I unplug the maf.. drives the same. I put the old maf back.. drives the same. Go to auto zone and get the code read.. Now i have a new code p0102 & P0112 ( Air intake temp Sensor ) Wait what? m62tu got a maf with integrated AIT???? so what the hell?? Which leaves me to where I am now. I am stumped. I dont know what to replace. o2 sensors? maf? Maf wiring? I checked every where i could see and couldnt see any vacuum leaks.. intake piping is all hooked up fine. I do have a cone filter in place of the box filter. but i've had that for a while and no issues..

Please help guys?

[geargrinder]

Pull real codes with a real BMW scanning software not that P-code bullcrap. You'll get much better info.

[jstern]

+1 on what gg said but I think that you've confused your ECU. You need to clear codes, reset adaptations (you'll need more than a generic OBDII scanner to do that) and drive the car normally for a while so the ECU can relearn normally without all the "flooring it" nonsense. Sorry but the rough driving does nothing.

BTW I've gotten those MAF codes before and as you've found out they have nothing to do with the MAF. In my case it was poor programming by the supercharger company with the ECU knowing something was wrong, couldn't figure out what was wrong and generated those MAF codes, performance problem.

[geargrinder]

Agreed - MAF codes can definitely be red herrings for vac leaks or other flow / mix issues.

[Nicolas H]

Ok so update so far, I cleared all the codes and reinstalled the MAF from the junk yard.. No more CEL and I drove car around for awhile, turned it on and off multiple times.. nothing. The car drives much better than before but it still doesnt feel 100%.. The scan tool I used was able to tell me everything going on with the car while its driving. I mainly paid attention to the intake air temp and maf reading. Both seemed to be fluctuating and responding, so I do not think the maf is bad. I am not sure now if the car has to re-learn and eventually it will start to pull harder again? or is there something more to this. Also where can I find that bmw scanning software? Thanks for all the help

[Mach540]

How are your O2 sensors working? Scan tool can read that for you.

[ImTheDevil]

Just out of curiosity, it would be worth looking at your fuel trims. If they're notably high or low, it is an indicator of issues as well.

[Jack A]

Check for water in your gas tank. It will give you a bunch of unrelated codes.

[geargrinder]

All that swapping and dis/re-assembly can sometimes mean you've fixed up a vac leak from a bad connection that you didn't notice so you end up with a 'mystery fix'.

[Nicolas H]

Hey everyone, I appreciate all the help and as a first time bmw owner its nice to know the community is nice as well! The car is running back to normal, after the new maf install, day by day, the car gradually got better and better. Then I realized why it wasnt 100%... I had developed a header leak! Header to cat area. Snapped two studs but replaced them quite easily and now shes back to normal!!! thanks everyone so much for all the input

- - - Updated - - -

That is one off thing I did kinda look twice at.. While on the code reader, it simply stated "INC" next to my O2 sensors.. Not sure what it meant? incomplete? no CEL though

[jstern]

INC does mean incomplete. This is a readout for the OBDII readiness monitors. The readout is used to display the results of the individual Emission System readiness tests on OBDII compliant vehicles. Such a vehicle must have all the monitors read OK to pass inspection in most US States.

When you clear a fault code, you also clear ther readiness status for the individual emission system readiness tests. In order to reset these monitors, the vehicle must be driven through a complete drive cycle with no fault codes in memory. You can Google E39 drive cycle to find out exCtly what that is or you can drive the car normally and see if the monitor shows OK.

Your exhaunt manifold leak might cause the monitors for the O2s to be incomplete after clearing your fault codes. I'd think that they'd be OK after some more normal driving.

[Nicolas H]

Thanks thanks! Well I thought all things were good now but it seems I've stumbled across a new problem! I just filled up gas today after being stupidly low (15 miles to empty) and I filled her up all the way 18.6 gallons. And I went to start the car. Except it didn't want to start.. It just kept turning over and turning over. Starter was working. All the lights on my.dash were working. So I stopped in fear of burning out the starter. Tried again and it started right up? Ok... So I drove to Randall's to get some groceries and I come back out side, and once again same exact issue. Just keeps cranking but no catch. Try again and it starts right up no issues what so ever. Car is ever so slightly sluggish as I'm missing my second gear wheel chirp. Figured well I've got a full tank so. But now I'm thinking maybe running the car to near empty probably caused alot of old gas and dirt and grime to resurface and circulate through the fuel lines, and maybe that's why it's having an issue starting?