If you look at the log the engine RPM is around 1790 rpm. so the engine is not shut down, but the maf is 0.

"Pending" P030X codes, occasional engine misfire
 

Yeah, I agree with you. But my understanding of how the logger works is that it triggers on a PID value change, thus certain readings may be a few seconds old when they are written to the file.

I certainly know that I turned off the engine (while coasting at highway speeds) to clear the limp mode.

You can tell when the misfires happened - when the fuel status values go to "8". After that happens (3 times in this file, all highlighted in yellow), I would have to power cycle the engine to clear the misfires.

Looking at the MAF readings in relation to throttle position and calculated load where the misfires did not occur, they seem to track accordingly and as expected, but I'm not certain as I'm only looking at numbers here while not fully understanding all the logic... ;-)

BTW - should the MAF voltage range be 0 to 5 volts? The range seems much wider than that in my log files.


Rookie48

More updates....

Replaced MAF
Replaced rear O2 sensors (previously only replaced front O2 sensors)

This made a small change - I can run between 65-75 MPH without any misfire codes being thrown. The engine is still stumbling slightly in this range (3000-3300 RPM). Stumble happens when at no or slight throttle and I am either letting off the throttle or accelerating.

It is still throwing only misfire codes across all cylinders at lower RPM's and at excessive highway speeds, again under the same throttle conditions as before.

Next steps (this weekend) are to:

Replace Vanos solenoids
Replace Cam sensors
Replace Crankshaft sensor

Vanos is not making any noise, and doesn't seem to be causing other typical symptoms (rough idle).

:dunno:

Slow down here a bit.

Do not think this is anything to do with the VANOS.

Crank or cam signal, maybe?? But I do not think so because you are not loosing the Tach signal.

I believe you are loosing fuel for some reason. I see you replaced the fuel pump and filter already.

The loss of fuel and the O2 sensors going fully Lean will cause the Fuel System Status to turn to 8 or got into an error mode. This also cause the Fuel Trims to default to 0 as well.

I would replace the fuel pump relay or swap the horn and fuel pump relay first and see what happens. You may even want to rig up a test light or LED to watch and see if the fuel pump drops out.

As for Logging with OBDFusion, here are some set up options.

First change the MAF reading from Pounds/Min to Grams/Sec, stupid EASY.

Settings, Units, Airflow, choose g/s.

Temp sometimes can be more useful in C vs F, but no so critical.

Settings, Log Setup then set the following:

Logging Enabled - checked

Logging Trigger - choose Trigger at a fixed sample time

Sample Time - choose 1000 msec

Log GPS Items - suggest you unselect it as to not advertise where you live

Select Items to Log - This varies a bit for each car. But here is a list I like to see:

Fuel - do not check any of these 3 items

JFOJ:

Thanks for the support here.... I swapped the horn relay with the fuel pump relay, as well as changed the two cam sensors and the crank sensor. (Horn worked fine under either relay switch)

The truck is still not running very smoothly, and has thrown the misfire codes P0300 through P0306, but has not entered limp mode yet. It also threw the following codes, but I'm not convinced the scanner tool didn't misinterpret some code as it doesn't store these codes in the diagnostic report:

C0303 - Starting letter C diagnostic code suggests that there are problems in controller area network wiring bus and modules. Maybe this is for injector #3?
P0203 - Injector Circuit #3 Open
P0101 - Mass or Volume Air Flow Circuit Range/Performance Problem

I changed the log file settings and am attempting to record the logs during a misfire/limp mode condition. Will post here when I capture the event again.

Do not see very many Cxxxx codes.

But based on what you are indicating, might be worth pulling the DME and inspecting the connectors for coolant or oil intrusion.

This is a very easy problem to identify and at least rule out as a possibility.

Not an E53, but still a BMW with a similar engine platform.

Fuel injector, possible DME issue? HELP! - E46Fanatics

Where might I find the DME control module on my 2003 X5 3.0i?

Under the dash behind the glovebox?

Attached is the log from today's drive into work. No limp mode, but the SES light came on at the 40 minute mark in the log (rows 506 to 565) - I assume that is when the misfire codes were thrown again. I hit the diagnostics button on the scanner while driving and got the screenshot attached. Weird codes again - but the diagnostic report doesn't show them at all!

https://dl.dropboxusercontent.com/u/...5%20AM%29.xlsx

https://dl.dropboxusercontent.com/u/...4/IMG_1372.PNG

https://dl.dropboxusercontent.com/u/...2015-12-23.pdf

The more I investigate this truck, the more I am convinced it is an electrical issue. Since swapping the horn relay with the fuel pump relay, the truck has not gone into limp mode. It has continued to throw misfire codes across all cylinders on almost every trip I take with it. This it might be a poor electrical connection to a sensor or the DME itself. When the truck is cold, and running in open loop mode (fuel status = 1) it idles fine, runs fine, no stumbles, performs well (although I'm usually not hammering it when it is cold). Once it enters closed loop (fuel status = 2), that's when the issues start.

One last thing that makes me think it is an electrical issue - today, other than the misfire codes being thrown, the truck ran great! I was at slower speeds, higher speeds (80+), and had no stumbles or rough running. I don't think it even gurgled through the exhaust... so something is working at times, but mostly not...

Can you put what model you have in your signature. Kind of annoying looking through an entire thread to figure this out.

In open loop, as in cold start, the MAF readings are being ignored. Have you tried unplugging maf and driving around without it. You will get check engine. Try it. Check intake boot for tares.