Misfires on Bank 1 - 02 4.6is
 

Hi All,

After sending my 02 4.6is to get the transmission repaired, it came back with a rough idle a the CEL on with codes 1341, 1343, 1345, 1347 & 1349... all on Bank 1.

Now this vehicle had been sitting for 2 years before I decided I wanted to drive it again so the first thing I did was fill the gas tank with fresh high-test fuel... I also cleared the codes and disconnected/reconnected the battery.

I spent a few days driving it hoping the issue would resolve itself but it hasn't... last night I decided to change the plugs to see if it would have an impact but it hasn't.

Looking at the codes themselves, I noticed that those are misfires related to fuel cutoff. I've spent the day reading other threads on the subject but haven't found a clear indication on what the issue might be.

-CCV - has never been replaced so not sure if that could contribute.
-Vanos solenoid?
-OSV? This has been changed in the past and hoses replaced but could the transmission shop have knocked the hose off and cause a vacuum leak?
-Other vacuum leak that would affect only one bank?
-Throttle body or MAF needs cleaning?
-Ground problem on Bank 1?
-Dirty injectors?
-Crank position sensor?

I unplugged the MAF as some have suggested and it had no impact. I should specify that this issue only occurs at idle and as soon as I touch the throttle, the engine smooths out and operates normally.

Tonight I plan on looking at the OSV again, cleaning the throttle body and possibly looking at cleaning/testing the injectors using this method (https://www.youtube.com/watch?v=ffdPCno5izU) and run a temporary ground to each injector.

Anything else I should consider?

Thanks
DF

fuel cut off usually occurs as a result of the system shutting down to protect the cats, which would indicate there is an incorrect (possibly!???) reading from the O2 sensors either before or after the cats. perhaps it would be prudent to check the O2 sensors ? or at least, swap positions with bank 1 sensor 1 and band 2 sensor 1 ?? (the two upstream sensors!)
just a though, I had a misfire with fuel cut off issue, and solved it with a new O2 sensor

To find out why you have the problem, you need to look at real time data. As been mentioned before, fuel cutoff is just the DME shutting the injector down so that the cats don't get destroyed by an overly rich mixture. You need to look at the long term and short term fuel trim for both banks. Looking at the MAF air flow wouldn't hurt either. You can also look at the 02 sensors and see what type of voltage they are putting out.

Thanks guys.... got sidetracked and didn't get to work on it tonight but I did get the messages in time to go pick up 2 o2 sensors... will try to install them tomorrow.

I do have DIS 5.7 I think but I bought it more than a year ago from a romanian guy on eBay and don't have the activation code to install it...

DF

You can buy a simple blue tooth scanner for under 20 bucks on Amazon or eBay. I use an App called Torque on my smartphone and tablet to read real time data on my X and my other cars with a OBD II DLC.

As with anything new apps, there's a learning curve on setting up the app and knowing what to look for.

Thanks... ordered from Amazon, should be here Friday!!

This place is great!

DF

Update
 

Ok... all 4 o2 sensors have been changed and it had no impact

I did receive my bluetooth obdII sensor and I am learning to use Torque...

I did try my test light to see if I have a good ground from my engine and I don't... I want to add a ground strap but I think there is one already from the factory... anyone know where it is?

DF

Precat 02 sensors only report the amount of oxygen in the mixture and the computer will adjust the fuel base on the o2 sensors and other sensors. Most of the time, 02 sensors rarely needs replacing. Looking at the 02 voltage readings on Torque would have shown you whether the sensors are working or not.

As for using the scope on a rope, did you connect the scope on the rope to the jump terminal in the engine bay and touch the tip of the scope on a rope to a Metallic part of the engine? Careful where you touch since there are a lot of plastic parts in the engine and as far as I know the German Engineers hasn't figured a way to make electric current pass through plastic.

Throwing parts at the BMW can be pretty pricey after awhile.

If the misfire is only at idle, but smooth out once the throttle is opened, then most likely you have a vacuum leak. Vacuum is highest at idle because the throttle plate is closed.

Real data (Short Term Fuel Trim) on Torque will show you if bank one is running lean compared with bank 2. If the Short term data shows a plus value that means the computer is adding fuel to the bank because the mixture is lean. If the number is negative, that means the bank is running rich and the computer is taking fuel away from the bank.

Learn to use Torque and report what the fuel trim data are for both bank.

MAF, CCV, OSV, throttle body or vacuum leak issues would not be limited to one bank. Injectors are individually grounded. The codes are ignition related and are on all four cylinders so it is highly unlikely there is an injector or coil problem. I suggest troubleshooting the camshaft position sensor for bank one.