Misfire, tough idle - fuel injector issue?

[ard]

you seem to be sure it is an injector issue. Throwing parts is expensive.

[xchen]

Originally Posted by ard

you seem to be sure it is an injector issue. Throwing parts is expensive.

@Art:

Honestly, I am not so sure about the #6 fuel injector (and alone) is the culprit.
However, it is a suspect since the non-BMW injector is not being programmed to the engine computer.

I don't know a way to identify vacuum leaks and other potential problems with the engine yet.

[xchen]

@Ard:

As I stated in my first note (#18) on this thread, the engine got a P0306 code (for cylinder #6 misfire) and ran rough and stall. I replaced the ignition coil and spark plug and the engine still runs rough but less stall and continue to have code P0306. So I moved on to replace #6 fuel injector. The engine runs slightly better (I have taken it on to local streets) but still runs rough on acceleration, and still has the code P0306 with the check engine light ON.

As M5James mentioned in post #14 with the last sentence that "they (meaning injectors) NEED to be coded so the car will run correctly with them." It is a reasonable guess that a genuine BMW fuel injector may not require the re-coding.

Experts like you and M5James may be able to tell if non-OEM fuel injectors would work on this X5 3.0si and if they need re-coding into the computer and how. I really have no clue.

I read through this thread and some have suggested that vacuum leak and lean condition could also cause misfire codes. But how do I identify them?

Yesterday I remove the newly installed #2 spark plug after about 15 miles and it has black coat on the tip. Does that mean "running lean?"

[ard]

You need to program each injector's 'flow compensation value' into the DME. So BMW injector or no-name, still needs to be coded.


The challenge, IMO, is with these aftermarket parts, who knows if they are actually measured properly.


If the DME doesnt have the correct calibration, that one cylinder can be too rich or too lean- each causing their own issues.


But Im not convinced it was a cylinder/injector issue- did you chase down the other paths raised in this thread? (or the other- I lost track)

[xchen]

Originally Posted by ard

You need to program each injector's 'flow compensation value' into the DME. So BMW injector or no-name, still needs to be coded.


The challenge, IMO, is with these aftermarket parts, who knows if they are actually measured properly.


If the DME doesnt have the correct calibration, that one cylinder can be too rich or too lean- each causing their own issues.


But Im not convinced it was a cylinder/injector issue- did you chase down the other paths raised in this thread? (or the other- I lost track)

Thank you Art: No I have not been able to start chasing potential vacuum leaks. JFOJ has mentioned using a ODBII tool (for which I have one) to monitor Fuel Trim values for identifying vacuum and crankcase air leaks and I have posted request for HOW.

[xchen]

@Art:

You mentioned that injectors have their "flow compensation value" and needed to be coded into the DME. How do I go about identifying these FC values?

The non-BMW injector that came from AutoZone just has a clear little plastic bag used to seal the injector inside and a paper packing box. There is not indication of a CF value anywhere.

And pardon me for my ignorance: what are DME and IMO?

[ard]

who is Art?





if you read the procedure for changing injectors at www.newtis.info, it will include EVERYTHING you need...pictures...words...



There is this thing called Google. You can type in 'what is DME' and I bet it will say "DME is Digital Motor Electronics which is BMW speak for the engine computer". IMO? All the hip kids use it to mean in my opinion

[xchen]

Originally Posted by ard

who is Art?





if you read the procedure for changing injectors at www.newtis.info, it will include EVERYTHING you need...pictures...words...



There is this thing called Google. You can type in 'what is DME' and I bet it will say "DME is Digital Motor Electronics which is BMW speak for the engine computer". IMO? All the hip kids use it to mean in my opinion

Sorry Ard for mistyping your ID.

Before responding to your last note I googled DME and I got "DME stands for Durable Medical Equipment" and Digital Motor Electronics was not mentioned in the search list.

As for IMO, now you cleared it for me and thank you - I though maybe there is another electronic box on the vehicle that has the name IMO.

[xchen]

Originally Posted by ard

who is Art?





if you read the procedure for changing injectors at www.newtis.info, it will include EVERYTHING you need...pictures...words...



There is this thing called Google. You can type in 'what is DME' and I bet it will say "DME is Digital Motor Electronics which is BMW speak for the engine computer". IMO? All the hip kids use it to mean in my opinion

@Ard:

The link in your post doesn't seem work.

[xchen]

Purchased a $60 OBD2/EOBD Scanner and here are the photos on reading of cylinders with the condition that there is a P0306 code. Notice that only Cylinder #6 has a high 348cnt Test Value, while others have either 0, or 5 and 8 Test Values.