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Discussion Starter #41
Sailor24

Just before I started doing the MAF tests several weeks ago, I did do a sustained rpm pull with the MAFs unplugged and ultimately was able to trigger a CEL due to misfires and I got the following results (taken from Post #23 above):

Unplugged the MAFs and drove +50 miles before I got to my testing spot. Drove the car in 3rd gear at +5500 to 6000 rpms for a sustained period. It seemed to take a little longer the CEL to activate, but it eventually did. Pulled over, scanned & cleared the codes, restarted the car and she drove fine. I went to the next exit and plugged back in the MAFs. Here are the codes I got:

29 (41) Signal, air-mass flow sensor, right
39 (57) Signal, air-mass flow sensor, left
4D (77) Signal, intake-air temperature sensor
C4 (196) Misfiring, cylinder 1 with cylinder cutout.
C5 (197) Misfiring, cylinder 2 with cylinder cutout.
C9 (201) Misfiring, cylinder 6 with cylinder cutout.
CC (204) Misfiring, several cylinders with cylinder cutout.


Is this worth trying again?

I'll need to look at how to scan both the long and short trim with my scanner. As you saw before, I'm not able to pass along what my scanner collects and have it be understandable on your end. Since I'm not able to pass the results along, I'm assuming I need to see what the trims are when the misfire occurs, correct? Is there anything specific I should be looking for?

Per the previous owner's thread (New E39 M5 owner, let me introduced you to her.) he mentions having changed the MAFs; however, I am not able to find them on the receipts he provided, nor am I able to find a date stamp on the MAFs, so I can not be 100% positive they are new within the last 20k to 30k miles.The ones that are on the car appear to be Bosch units with BMW part matching numbers.

Thank you,
 

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No I think you have enough to assume the MAFs are fine and this also rules out any above throttle air leaks. That narrows it down. It does not rule out below throttle leaks which would also include the injector orings, the fact that the codes are pretty constant on those cyls sort of rules out any air leak that is not on one of those cyls that are throwing the misfire codes. It could be one of the ICV orings connecting to one of those cyls, but those behave a little different and have symptoms when you get off the throttle. The vacuum jumps then sucks air into those cyls, the injector orings do present the symptom you have.
You are talking yourself in to look at the injectors but that is a rabbit hole in itself because it is so much work, you might as well do more work while there.
If it was me while pulling things a part I would spray a flammable fluid into where the injectors sit once I had the plenum off, with the car running. The problem with that is since you issue only happens at high rpm and big load on the rings, it will likely have no results because it might not leak under low vacuum. Ask about that and how to do when you decide you are going to look at the injectors.
Don't forget it still could be those drivers in the DME that are getting worked hard at high rpm. Another rabbit hole.
If you don't hit high rpm often maybe the thing to do is keep driving it until the condition gets a little worse and points you in one direction or another.
 

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Discussion Starter #43
Thank you @Sailor24.

Since this doesn't appear to pose an immediate issue, this may have to get put on hold until my finances become more stable. As you said, once I'm into it that far, I might as well replace other components that should be replaced as I go through the process of getting to and cleaning / replacing the injectors.

Until then, I will continue to go through the process of looking to source fuel injectors if there are any out there that are a factory (or near facotry) alternative to the ones offered by either ECS Tuning and FCP Euro. I do believe however, I have found a local shop for injector cleaning (Fuel Injector Specialists - Home - Wheat Ridge, CO). I still need to call them about their processes, but to date I haven't heard anything negative about them.

I will follow up on this thread once I start the process of if anything changes related to this issue.

Once again, thank you,
 

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Hi, same exact problems as yours illustrated in my thread below. Unfortunately almost two years in I am still not able to figure out what is causing it. I have replaced everything short of injectors. Appears that you are on that path as well.
Since my latest post, crankshaft sensor and a second round of MAFs.


my car also potentially has a Dinan software upgrade. I am thinking of running to a local Dinan dealer and having them check that out and possibly reflash.
 

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Discussion Starter #45
@diman242424,

Thank you for your input. I believe I am at the stage of injector removal and testing, but this will take some time due to finances in the current times. I will probably post once I'm about to start the injector removal.

I haven't done much searching since my last thread, but I'm still hoping to get a line on injector replacements other then the ones currently offered by ECS or FCP. If I have to go the BMW Genuine (with their prices) route I will, but I'm still looking for OE replacements.

Thank you,
 
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