2002 530 (M54b30) rough idle and check engine light

[henryki]

EDIT: The problem has been resolved!

Lesson learned, if you're throwing lean + rich codes and the motor is idling rough, learn from my mistakes and double check to make sure your O2 sensors are connected to the correct plug! Sounds dumb I know, but I bought the car with the rough idle and never thought to take a look at how the O2 sensors were plugged in. ​ :banghead:


The issue:
If it's above 1,000 RPM it runs perfect with no issues at all until you are at full throttle past 4,500RPM where the power delivery feels as if it is surging.


P0175 - mixture control 2 system too rich bank 2
P0172 - mixture control system too rich bank 1
P1084 - fuel control mixture rich bank 1 sensor 1
P1085 - fuel control mixture lean bank 2 sensor 1




The work I've done so far:
- New vacuum lines from EGR valve (part #11727540468) to the electric valve (part#11747810831)
- New vacuum lines/caps from electric valve to the intake manifold the only thing that I haven't replaced there was the one way valve (part #11611312737)
- New intake manifold gaskets
- New sucking jet pump (11617545382) (includes hoses and F connector that connect to the intake boot and hoses that connect under the manifold)
- Fuel tank breather valve hoses under the manifold(did not replace the valve itself)
- New PCV + hoses (plus new o-rings for the dipstick tube & air distribution piece on top of the manifold)
- Intake boots
- New Siemens MAF from Pelican Parts
- New camshaft position sensor (both intake and exhaust)
- New DISA unit
- Cleaned ICV
- New Mann fuel filter (with built in FPR)
- New air filter
- Fuel injectors looked clean and no residue on them whatsoever








The only vacuum related things that I can think of that I haven't done yet would be:
- The larger o-ring that seals the MAF to the air box
- Throttle body o ring.
- ICV Gasket
- valve cover gasket
- Intake air temp. Sensor?




Aside from vacuum lines could it also be my vanos acting up?
bad O2 sensors?
Or no fuel tank ventilation? (clogged carbon container)
http://www.realoem.com/bmw/showparts.do?model=DT63&mospid=47587&btnr=16_0496&hg=16&fg=10




Any ideas or suggestions would be greatly appreciated.
Thanks!

[henryki]

Bump

[henryki]

Bump.

could there also be enough of a vacuum leak from the top of the sucking jet pipe to the hose connecting to the brake booster to cause a rough idle situation?

My brakes do do need to be changed but under heavy freeway braking the rotors feel as it they are warped. But under normal breaking they stop smooth. So could the warped rotor feeling be coming from a vacuum leak?

with how much time I've spent working on this car I'm open to any and all suggestions and I don't want to sell it with CEL's on.


HALP ANYBOOOODEEE

[henryki]

Bump!

So after replacing the valve cover gasket, I dropped P0185 (fuel control mixture lean bank 2 sensor 1) and picked up P0186 (fuel control mixture rich bank 2 sensor 1)

Now that I have no lean codes, it seems to me that I have resolved all my vacuum leaks but I'm stumped as to why I still have rich codes.
Could it be the computer trying to figure out the right mixture since it was running lean for so long?

engine-codes.com states that the probable causes for codes P1086 & P1084, could be:
- Low fuel pressure
- Large vacuum leak on engine
- Faulty Mass Air Flow (MAF) sensor
- Faulty Ignition
- Faulty fuel injector

and for P0175 & P0172
- Faulty front heated oxygen sensor
- Ignition misfiring
- Faulty fuel injectors
- Exhaust gas leaks
- Incorrect fuel pressure
- Faulty Mass Air Flow (MAF) sensor

From my earlier post you can see that I have replaced the MAF, and fuel filter/fuel pressure regulator.
Just last night I also replaced the spark plugs with OEM plugs, which made the car run slightly better.

I don't want to keep throwing parts at it to try and resolve this issue, does anybody have anything to add that I might be able to do in order to resolve this issue?

Thanks.

[RuskiE39]

My wifes car got a cylinder miss fire code P1345... felt exactly as your describing... sounded like a train and was chugging at under 1K rpm, I never "got on it," though to see what the higher rpms felt like. I went to an auto place to get the codes read, cleared them, and the car drove perfectly. My scenario is most likely an ignition coil or spark plugs... have you tried those?

[henryki]

My wifes car got a cylinder miss fire code P1345... felt exactly as your describing... sounded like a train and was chugging at under 1K rpm, I never "got on it," though to see what the higher rpms felt like. I went to an auto place to get the codes read, cleared them, and the car drove perfectly. My scenario is most likely an ignition coil or spark plugs... have you tried those?

I just did the spark plugs last night but I don't have any coils to swap around to figure out which ones are bad (if they are).

As soon as I did the plugs and started the car it threw up misfire codes on start for cylinders 2 + 3, which are codes P1345 and P1344 I believe, don't remember off the top of my head. But when I scanned the car again today the misfire codes were gone and just the 4 codes (P0175, P0172, P1084, P1086) remained.

[Flounderasu]

I just did the spark plugs last night but I don't have any coils to swap around to figure out which ones are bad (if they are). As soon as I did the plugs and started the car it threw up misfire codes on start for cylinders 2 + 3, which are codes P1345 and P1344 I believe, don't remember off the top of my head. But when I scanned the car again today the misfire codes were gone and just the 4 codes (P0175, P0172, P1084, P1086) remained.

Swap 2&3 with 1,5,or 6. Clear codes and restart. If the codes pop up and they move to the ones you swapped, you found the bad coils.

[RuskiE39]

Swap 2&3 with 1,5,or 6. Clear codes and restart. If the codes pop up and they move to the ones you swapped, you found the bad coils.

This... when you plug them back in the one that changes idle is most likely the bad one.

[bimas]

+1. Sorry, I had more info. But I realized that it pertains to N52. My bad.

[henryki]

I didn't swap anything around and again no misfire codes for 2 & 3 but now there's misfire on start codes for 4, 5, & 6.

So lost, but I'll try swapping them around in the morning and post my results

[henryki]

Started the car this morning and scanned it, all misfire codes disappeared but all the rich codes remain. I'm going to take it to be diagnosed by a local mechanic later today. This seems to be an issue with e39's with the m54 motor and tends to go unresolved. With these vehicles aging more I think it's only fair to share what ended up resolving the issue, keep yall posted. Thanks again for the replies.

[Flounderasu]

Started the car this morning and scanned it, all misfire codes disappeared but all the rich codes remain. I'm going to take it to be diagnosed by a local mechanic later today. This seems to be an issue with e39's with the m54 motor and tends to go unresolved. With these vehicles aging more I think it's only fair to share what ended up resolving the issue, keep yall posted. Thanks again for the replies.

I'm guessing Vacuum leaks....

[henryki]

Problem resolved!!

the previous owner replaced the O2 sensors. And when he did he plugged the bank 1 sensor Into the harness slot for bank 2.

So cylinders 1-3 were getting the O2 sensor readings for 4-6 and vice versa.
DOH, I can't believe that I never thought of that.

[RuskiE39]

Problem resolved!!

the previous owner replaced the O2 sensors. And when he did he plugged the bank 1 sensor Into the harness slot for bank 2.

So cylinders 1-3 were getting the O2 sensor readings for 4-6 and vice versa.
DOH, I can't believe that I never thought of that.
Nice! Good to hear.. label your plugs people.

[henryki]

Nice! Good to hear.. label your plugs people.
+1

Whenever I'm dealing with plugs I always label everything, critical especially when I took the manifold off to do manifold gaskets.

But I was just on the verge of replacing my pre-cat O2 sensors so I'm glad that the old ones are still good.


Again, thanks for all your replies, and the car is for sale now! And it has had lots of preventative maintenance recently done hahaha.

[Mitsos]

I'm glad you solve your problem .
What is the mileage on the car?

[bullard123]

Why are you selling it? With the codes gone it should be a blast to drive now. Is it auto or manual?

[henryki]

Why are you selling it? With the codes gone it should be a blast to drive now. Is it auto or manual?

It is really nice to drive but I went from an 1990 5speed E30 with a LSD and a m20 with a mild cam+tune to this. And being auto it's super nice to just cruise around in but Im not liking it as much as I thought I would. Granted it's a super nice car and I searched for a long time to find it (had to be face lift black leather interior + sport package), but I'm 21 and right now I'm more interested in a fun car. One of my friends is selling his e21 and I wanna get that instead.
And if I end up getting it, a single head light and euro bumper conversion is in order. I'm not into that "stance" bullshit so it wouldn't be slammed, just lowered on some h&r's or something haha.

[henryki]

So a little update on the car, I had a buyer lined up to buy the car. But I don't think this car wants me to sell it because I got the dreaded P0741 code for the torque converter slipping too much.

Considering doing a manual conversion, which mechanically will be straight forward and not an issue. But it's the software that I'm concerned about. I know there's a lot of threads out there regarding the subject of doing a manual swap. And after completely reading through Stück's 3.0zhp and 6 speed manual swap on his 01 525 I have some glimmer of hope. So if anyone knows what it'll take to program the DME to thinking it has a manual, or program it so it ignores all the codes that'll be thrown from the lack of an auto box?

[BabyAlex]

Bummer! Was very interested in your car. Hope you get that sorted out for not too much $. Know that can be an expensive fix. Best of luck with the repair.

[sleuth255]

Whoa! Wrong connections? How the heck can that even happen? The pre-cat O2 wires have a pretty specific routing pattern. Must've been a real id10t that did them. Glad you got it sorted!

[henryki]

Bummer! Was very interested in your car. Hope you get that sorted out for not too much $. Know that can be an expensive fix. Best of luck with the repair.

damn... haha well its a good situation for you not getting stuck with this problem!


Whoa! Wrong connections? How the heck can that even happen? The pre-cat O2 wires have a pretty specific routing pattern. Must've been a real id10t that did them. Glad you got it sorted!

The previous owner claimed to be a "diesel mechanic" and since this is my first M54 car I didn't know any better... So while the previous owner is a complete dumbass, half of that also falls on me haha. But you can be sure that from now on, if an M54 is having a rough idle with Lean+Rich codes, that'll be the first thing I check.