Another weird issue with X5

[PEV]

Hi, I am another "lucky" owner of 2001 X5 3.0. Although I love it when it drives and the way it handles the road (I have manual stick), but unfortunately most of the time I spend fixing it... The last one is the weird one. I did find another post where someone had exactly the same issue back in 2011, but there was no resolution/follow-up, so I have no idea if it was fixed or how. Here is the story:
Started from it stalling on the road - was a traffic jam and everyone was moving really slow. My X5 started losing power and couple of times there was a loud bang from the engine (almost like shooting rifle sound). I stopped and could not start the engine after that. Called tow truck and brought it to the local BMW garage. It was closed and as I was waiting for someone to pick me up, I tried starting the car - it did!!! I could even move it to another parking spot. But still decided to leave it with the mechanic as it did not run properly with low torque.
Next day I visited them to learn that they ran diagnostics and discovered that the 2 sparks misfired. Suggested that I replace all 6 which I did (and all 6 plugs as well). Could drive a car for 5 minutes after that and than it lost power and stalled again. Next recommendation to replace the fuel filter. Done. Can start the engine, but no power and when I try accelerating - nothing. As if I do not press the pedal into the floor.. Removed the first plug and noticed that it is not "burned" - looks brand new. Disconnected the cable from that coil (#1) and behavior of the car did NOT change. That tells me that one of the (the only???) issues is that spark plug #1 does not ignite. Although coils are brand new, decided to switch 1 and 2,- the issue stayed on #1 (eliminates the coil). Did not try switching plugs.. could it be bad plug?
What can possibly cause this and how/what can I test now? I took my car away from that shop as no real help from them and doing it myself now.
Any help / advise would be greatly appreciated!!!
Thank you!

[epdarks]

If it is a bad plug, that is an easy fix. Try that first.

You can test the coils by doing your same method... swap to another cylinder.

I assume you are getting a CEL after you misfire... what do your codes say?

[TerminatorX5]

knowing the codes is essential... did your original story with bang sound like a backfire on the old cars?

we just helped a fellow (diddy0071) troubleshoot something similar... you go in order from simplest to the most complicated.

you replaced the spark plugs and the coils - what brand of each did you use? was it is BMW original, or BOSCH (or other OEM)? or, was it some off-brand made on some unknown island in Asia?

since you are venturing into the engine diagnostics, i would strongly suggest buying diagnostic software INPA, GT1 along with the OBD to USB cable - in your case you also might need to buy the 20-pin round cable adapter for the data port in the engine bay. with diagnostic software at hand, you can read the codes, reset them, watch the new codes being set in the system, you can watch the live engine performance...

with that info at hand, you can throw more information on this forum, and i am sure, there will be somebody who can pinpoint the problem for you...

doing the diagnostic without the sotfware is like flying blind - you need to be helluva good mechanic to know what is happening there... or, keep throwing parts at the problem... which, after the fuel filter, next one will be fuel pump...

did you read this thread - http://www.xoutpost.com/bmw-sav-foru...essing-up.html?

[PEV]

Thanks a lot, guys! I did place the order for the software to read the codes about 4 weeks ago and it is still did not arrive. I guess, coming from China. And yes, I agree,- let me get the software and the cable and I will be able to provide codes. We will look into this after I get more info.

As for coils and plugs, they are Bosch and I just replaced the plug that did not fire and nothing changed. So, that eliminates the plug and the coil...

[TerminatorX5]

If DME determines that an issue with a cylinder severe enough, it will cut the power to that spark plug until the issue is resolved.

here some information - food for thought...
Smooth-Running Value and Misfiring Detection




The smooth-running values of the individual cylinders are indicated for troubleshooting purposes.
The engine must run at idle speed for at least 3 minutes to ensure that the correct values are set. Smooth idle speed can only be evaluated with the engine running at idle speed (cold or hot). An indication of the combustion quality of individual cylinders can be obtained by evaluating the crankshaft acceleration, measured at the crankshaft position/rpm sensor. An individual cylinder with poor combustion can be detected very well in this way.
Random fluctuations of the individual cylinders can only be detected by close observation of the value. The values over all cylinders are zero in the engine with theoretically uniform combustion.
An increase in the smooth-running values may be caused by various factors (e.g. misfiring, secondary air, mixture deviations, faults in fuel supply, low compression). For this reason, exact intervention limits cannot be specified.
The rotational speed (engine speed) of the engine is measured at the incremental wheel with the aid of a hall-effect sensor. Moreover, the smooth running of the engine is also monitored (misfire detection) as a measure of the engine speed.
To detect misfiring, the increment gear is divided (by the control unit) into 3 segments corresponding to the ignition interval, i.e. 3 sparks per crankshaft turn on a 6-cylinder engine and 2 sparks in 2 segments on the 4-cylinder engine. Within the control unit, the periodic duration of the individual increment gear segments is measured and statistically evaluated. For each point on the characteristic map, the maximum permissible rough running values are stored as a function of engine speed, load and engine temperature.
If these values are exceeded within a certain number of combustion cycles, the cylinders detected as faulty are stored in the fault code memory.

Uneven running data and misfire detection

The uneven running data from the individual cylinders is used by the digital engine module (DME) to detect misfiring.
Function

Analysis of uneven running data is only possible when the engine is idling. The engine temperature and load affect the data. Therefore, thresholds only ever apply under defined general conditions:

• Engine at operating temperature

• All auxiliary consumer units (air conditioning, rear window heater, ...) off

The crankshaft sensor is used to obtain uneven running data. This sensor continuously measures crankshaft acceleration. Analysis of the signal by the DME allows conclusions to be drawn about the quality of combustion in individual cylinders. Individual cylinders with poor combustion can be identified very well in this way.
Theoretically, when combustion is perfectly even, the values for all cylinders are zero.
There are various factors which can be the cause of uneven running:

• Differences in mixture between cylinders

• Misfiring

• Extraneous air

• Problems with compression in the combustion chamber

• Inadequate fuel supply

• Poor fuel quality

Because of this wide variety of possible causes, precise thresholds for intervention cannot be defined.
For the purposes of detecting misfires, the crankshaft-sensor incremental gear is divided by the control unit into:

• 2 segments in the case of 4-cylinder engines (2 ignitions per crankshaft revolution)

• 3 segments in the case of 6-cylinder engines (3 ignitions per crankshaft revolution)

• 4 segments in the case of 8-cylinder engines (4 ignitions per crankshaft revolution)

• 6 segments in the case of 12-cylinder engines (6 ignitions per crankshaft revolution)

The DME measures and continuously analyses the periodic interval of each individual segment of the incremental gear. For each point on the characteristic map, the maximum permissible uneven running values are stored on the DME as a function of engine speed, load and engine temperature.
Diagnosis

If those values are exceeded for a certain number of combustion cycles, the cylinders on which faults are detected are stored in the fault memory. Depending on the severity of the misfires detected, fuel injection for the cylinder concerned may be shut off.
The OBD lamp (MIL) on the instrument cluster is always switched on whenever misfires are detected.

[upallnight]

Again, sounds like a dying fuel pump. Check the pressure at the fuel rail to see what type of pressure the pump is producing.

Here's another thread where it was the fuel pump.

http://www.xoutpost.com/bmw-sav-foru...essing-up.html

[PEV]

I finally got the codes:
P1083 - Fuel Control Limit Mixture too Lean (Bank 1 Sensor 1);
P10345 - Misfire Cylinder 2 with Fuel cutoff;
P10343 - Misfire Cylinder 1 with Fuel cutoff;

Could it be just bad fuel? Or something more serious? Any help would be greatly appreciated.
Thanks!!!

[TerminatorX5]

you need to reset the codes, switch the coils from cylinders 1 and 2 for two other cylinders, like 3 and 4, start the engine , run the diagnostics and see if you get codes for the cyls 3 and 4... or, codes for anything else.. or, the codes will stay with 1 and 2... then, based on that info, you might need to change the coils or the spark plugs to the affected cylinders

once you have those rectified, then reset the codes again, and fire up the engine... see if the codes come back, or they are taken care of... once the cylinders are done, the fuel control code may go away on its own, if it doesn't, then we need to dig deeper...

[PEV]

The problem is, that the engine would not even start any longer. Starter goes on, the engine gets some power and then immediately idles. So, I can't get new codes (was told that in order for the codes to be updated, the car needs to run for a while). Sorry - I did not properly described the issue.
Once in a while it does run for 10-15 seconds with no power (I push accelerator into the floor with no results).
I did install new set of coils and plugs after the problem appeared and it did not change anything.
Another thing that I did not probably mentioned, - is that the car was sitting in my garage for almost a year with the tank half-full. After that it was running, but was idling quite often on stops. I was advised to add fuel conditioner, which I did together with new fuel. I was running on the same tank when problems started. That is why I am asking - could it be just remains of that fuel causing the issue? I know it sounds silly, but still.. Speaking of which - is there any simple way of draining the tank?

[upallnight]

Here we go again, why don't you just rent a fuel pressure gauge from the local auto parts store and check the fuel rail pressure. Just turning the key to the run position will initialize the fuel pump and you should be able to get a fuel pressure reading even if the engine doesn't start.

You could also have to bad coils. Swap them out with coils 5 and 6 and see if the misfire don't move to cylinders 5 and 6.