Misfire and clutch

Tiny
NASER NASER
  • MEMBER
  • 2004 BMW 525I
  • 6 CYL
  • 2WD
  • MANUAL
  • 72,000 MILES
Clean car listed above with the M54 engine. Misfires on cylinder one. Thinking it could be the coil since they are notorious for it. Switched cold around, nothing. Bought a new coil, still. The misfire goes away and check engine light goes off while driving randomly and the car drives perfectly. Compression is around 130, thought maybe the ring is a bit sticky, so added some Rislone compression repair and started driving it, the check engine light went away sometimes, and that is only after I added this stuff. So hopefully it is helping. But I want to test the wire going to the coil. Is there a way to do that? What else could it be? Another issue with it is that the car while idling and parked has a similar to a knocking sound from the clutch, but when I press the pedal that goes away and the engine misfires decreases a lot.
Tuesday, October 15th, 2019 AT 8:57 AM

43 Replies

Tiny
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Welcome back:

The knocking sound is most likely related to a release bearing issue. The only way to confirm is to remove it.
Is the compression 130 on all cylinders?

Let me know.

Joe
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Wednesday, October 16th, 2019 AT 6:59 PM
Tiny
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I just rechecked the compression and its 130 or so on all. When first started in the am mo clutch bearing sound and the car is 95% smooth and very minor misfire. Here are the fuel trim numbers. I will report with the numbers again after she starts to misfire while idling, am starting to think maybe the injector? 72,000 miles though that usually isn't an issue.
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Thursday, October 17th, 2019 AT 6:47 AM
Tiny
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Still no major misfire but here are the readings when warm:
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Thursday, October 17th, 2019 AT 7:21 AM
Tiny
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Found this to not sure what it means. After I switched over injector 1 to 2, swapped, waiting to see if she will set the same code as cylinder one, once warm.
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Thursday, October 17th, 2019 AT 2:07 PM
Tiny
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Sane code again number 1 but with number 2742.
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Thursday, October 17th, 2019 AT 2:14 PM
Tiny
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Welcome back:

Bank 1 is overcompensating for a lean mixture. What all have done to check for a vacuum leak? Are you certain there are no exhaust leaks pre cat on bank 1.

Let me know
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Thursday, October 17th, 2019 AT 7:08 PM
Tiny
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I thought this car only has one bank since it's inline 6.
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Friday, October 18th, 2019 AT 5:36 AM
Tiny
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Just did a vacuum leak test and saw nothing.
All cylinders have 130 psi or for
plugs and coils are okay.
With the scanner turning injectors off while engine is running causes a change, including number 1, and that is when the car is warm and hardly misfiring (5%misfire felt).
Intake boots look okay.
Swapping injectors causes no change in the #1 misfire.
The misfire is worse after 30 minutes of idle especially when the throw out bearing knocking noise surfaces.
Takes that long going from pretty smooth idle to check engine light coming on and the knocking for that to happen.
Is it possible the knocking from throw out bearing putting a stress on the motor and hence causing the misfire?
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Friday, October 18th, 2019 AT 8:09 AM
Tiny
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Welcome back:

You know, and this is a long shot, I wonder if the noise is causing an issue with the crankshaft position sensor, Think about it, if it is banging on the crankshaft via the clutch, it could be causing an erratic signal from the sensor. I have no idea if you have an oscilloscope to test the signal from the sensor. However, if you do, here are the directions and what you should expect to see. I have no idea how bad the knock is you hear, but it could even be related to the crankshaft thrust bearings which commonly wear out faster with a manual transmission. In addition to the test below, check the crankshaft at the harmonic balancer for excessive end play.

Here are the directions I mentioned. The attached pics correlate with the directions.

__________________________

2004 BMW 525 (E60) L6-2.5L (M54)
Set Oscilloscope Display Crankshaft Sensor [FUB-SOW-FIN0201SO47TU001 - V.4]
Vehicle Powertrain Management Sensors and Switches - Powertrain Management Sensors and Switches - Computers and Control Systems Crankshaft Position Sensor Testing and Inspection Oscilloscope Patterns and Waveforms Set Oscilloscope Display Crankshaft Sensor [FUB-SOW-FIN0201SO47TU001 - V.4]
SET OSCILLOSCOPE DISPLAY CRANKSHAFT SENSOR [FUB-SOW-FIN0201SO47TU001 - V.4]
Functional description
Set oscilloscope display crankshaft sensor
FUB-SOW-FIN0201SO47TU001 - V.4

Signal at idle:

Pic 1

Signal at starting speed:

pic 2

Let me know what you find

Joe
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Friday, October 18th, 2019 AT 6:45 PM
Tiny
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Can that be done using a scanner? If not then no I do not have one.I will check the harmonic balancer for sure, the thing about thrust, well, I doubt, because the noise goes away when I press the clutch deal, so definitely a clutch issue correct?
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Friday, October 18th, 2019 AT 8:22 PM
Tiny
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If it goes away when you depress the clutch, that would be my first suspect.
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Friday, October 18th, 2019 AT 10:18 PM
Tiny
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So what would be my next move here?
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Saturday, October 19th, 2019 AT 5:46 AM
Tiny
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Car acting crazy, after I installed the injectors back it runs the same, but I have an o2 code now.
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Saturday, October 19th, 2019 AT 10:47 AM
Tiny
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And sometimes these codes:
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Saturday, October 19th, 2019 AT 10:57 AM
Tiny
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Welcome back:

The codes indicate a misfire and an issue with fuel mixture. Are you sure the O2 sensor is properly installed and the connection is proper? Was it a bank one sensor? Can you provide me the short term fuel trims so I can see what is happening?

Let me know.

Joe
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Saturday, October 19th, 2019 AT 5:58 PM
Tiny
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I didn't even disconnect the wires for the o2 sensors, just did lay them on the side to get to the injectors, weird, and they have different lengths so am sure they are okay. I will get the readings for the fuel trims tomorrow.
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Saturday, October 19th, 2019 AT 6:31 PM
Tiny
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Sounds like a plan. Let me know what you find.

Joe
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Saturday, October 19th, 2019 AT 7:01 PM
Tiny
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I took it to the dealer hoping they can find something. I told them I have already swapped coils plugs injectors, so what did they do? Did the same thing and found nothing and want to charge me $188.00 for that, and want $461.00 to do a leak down test. I told them never mind. The service manager suggested I do a leak down test. Is that different than the compression test I did?
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Thursday, October 24th, 2019 AT 11:11 AM
Tiny
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They just gave me a sheet with couple of things, dme: misfire cylinder 1, and dme: fuel trim, bank 1, both present.
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Thursday, October 24th, 2019 AT 11:13 AM
Tiny
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Can you tell me what the fuel trim are? That will help point me in the right direction.

As far as the leak down, they do a compression test differently? Rather than having the engine produce the pressure, a leak-down test relies on an external supply of compressed air which is injected into one cylinder at a time.

Joe
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Thursday, October 24th, 2019 AT 6:25 PM

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