2005 E53 4.4i N62 Misfire Help!

[kamhoe]

I need some advice or guide to troubleshoot the misfire that never go away!

The service light recently pop up and I did the code scan and found

VIN: ...LV13586
Mileage: ~69250
Symptom: Engine keeps shaking; losing power; service light blinking on starting and stay on

2019-02-23
Current Fault Log
------------------
P0300: Random/Multiple Cylinder Misfire Detected
P0303: Cylinder 3 Misfire Detected
P0305: Cylinder 5 Misfire Detected
P0306: Cylinder 6 Misfire Detected

Pending Fault Log
------------------
P0301: Cylinder 1 Misfire Detected
P0303: Cylinder 3 Misfire Detected
P0304: Cylinder 4 Misfire Detected
P0305: Cylinder 5 Misfire Detected
P0306: Cylinder 6 Misfire Detected
P0308: Cylinder 8 Misfire Detected


I replaced 8x NGK BKR6EQUP spark plugs and did a few new scan on different dates and found


2019-03-02
Current Fault Log
------------------
P0300: Random/Multiple Cylinder Misfire Detected

Pending Fault Log
------------------
P0301: Cylinder 1 Misfire Detected
P0303: Cylinder 3 Misfire Detected
P0305: Cylinder 5 Misfire Detected
P0306: Cylinder 6 Misfire Detected


2019-03-09
Current Fault Log
------------------
ECU reports no current faults

Pending Fault Log
------------------
P0305: Cylinder 5 Misfire Detected


2019-03-10
Current Fault Log
------------------
P0300: Random/Multiple Cylinder Misfire Detected

Pending Fault Log
------------------
P0301: Cylinder 1 Misfire Detected
P0302: Cylinder 2 Misfire Detected
P0305: Cylinder 5 Misfire Detected


So I decided to replace 8x Bosch 0 221 504 464 coils and did new scan and found

2019-03-17
Current Fault Log
------------------
P0300: Random/Multiple Cylinder Misfire Detected

Pending Fault Log
------------------
P0301: Cylinder 1 Misfire Detected
P0304: Cylinder 4 Misfire Detected
P0305: Cylinder 5 Misfire Detected


I am thinking of the fuel injectors that cause the misfire and I found the guide on

https://www.pelicanparts.com/techart...eplacement.htm

I am wondering if this is the correct guide for my N62 engine?


I never deal with fuel injectors before and I curious if this not too tough can be done by myself in my yard?


I have some experiences for battery, spark plugs, ignition coils, window regulator replacement & dashcam hardwiring.


I welcome anyone's advice and info to fix the problem!

[andrewwynn]

I would stay with cleaning with techron or equivalent. I had good success with Lucas injector cleaner. Wife's car started having similar creeping m random misfires. First just in on one cylinder, I swapped that coil then it just moved to a different cylinder. Swapped one more coil then I ran a bottle of injector cleaner through 1/2 a tank of fuel and haven't had a shaky start or engine code since (at least a month now).

[kamhoe]

Originally Posted by andrewwynn

I would stay with cleaning with techron or equivalent. I had good success with Lucas injector cleaner. Wife's car started having similar creeping m random misfires. First just in on one cylinder, I swapped that coil then it just moved to a different cylinder. Swapped one more coil then I ran a bottle of injector cleaner through 1/2 a tank of fuel and haven't had a shaky start or engine code since (at least a month now).

Are you suggesting to pour in an injector cleaner 1st before removing those injectors? How long do I need to run the car to see the result?


I think I watched the Lucas cleaner on YouTube yesterday & I will give a try!


Thanks!

[andrewwynn]

i was about to buy an injector cleaning tool (they actually are an in-car tool you don't need to remove), but it dawned on me in most of four years ive never run injector cleaner through either of our cars which were both kicking in SES sporadically but too often.

Put in half a tank of gas in each car, reset codes, no codes either car in a month. I did a nice long drive each car at least an hour to 90 minutes after putting in the Lucas cleaner.

I could feel the difference in throttle response within ten minutes of driving it was clearly making a difference.

I think I'll add to my regular maintenance probably six month interval including just before winter since those cold starts are the hardest on the engine.

[EODguy]

This is the BMW & Mercedes authorized injector cleaner and I highly recommend it but it is some vicious stuff and one little can treats 65 liters. Do NOT let it touch your skin, as it absorbs fast enough that you can taste it pretty quickly from contact. I'll translate the name and get a better picture when I get home tonight.

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[EODguy]

Here's the other side

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[kamhoe]

Originally Posted by EODguy

This is the BMW & Mercedes authorized injector cleaner and I highly recommend it but it is some vicious stuff and one little can treats 65 liters. Do NOT let it touch your skin, as it absorbs fast enough that you can taste it pretty quickly from contact. I'll translate the name and get a better picture when I get home tonight.

No luck to find this additive online for US region!

I went to local Walmart and bought this Lucas Fuel Treatment. I poured in 4oz but haven't got any chance to run the car yet due to my jobs. Probably will do a long run on weekend!

I also found that BMW are using re-branded Techron fuel additive from the post of https://xoutpost.com/bmw-sav-forums/...icks-info.html

[EODguy]

You should be able to get it at the stealership either BMW or Mercedes. It's a very small can about the size of the little V8 juice cans, but missing online doesn't surprise me cause that crap is vicious.

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[stiubhartach]

While injectors can cause lean misfire, the ECM will usually adjust by advancing the timing to prevent detonation.

Your problems sound more likely to be ignition related than fuel.

Since you replaced the plugs and the coils, the most likely culprit is the unseating of the coils.

From the Bosch website. More at the link:

“With the newly-designed coil, the customary “snap” is no longer heard nor is it an indication that the coil has been properly installed. This new design does, however, provide better coil performance at the spark plug connection point, which was the area that concerned some technicians. In other words, the original design actually gripped the spark plug tip and felt more secure; whereas the new design uses a contact spring on the spark plug tip and this design may not feel like the connector is gripping the spark plug – but in reality it does the job just as well or better than the old design.”

https://www.boschautoparts.com/en/au...ignition-coils

[stiubhartach]

I actually just did all eight of mine yesterday, and initially had misfires on 1,2, and 7. Had to reseat them.

Pull the coils on the affected cylinders, lubed the TOP rubber boot with light silicon spray (NOT the plug boot!). Reseat them, twisting and ensuring the top seal sets down fully against the head. Make sure they’re all the way seated before you plug-in the connector socket and flip down the hold down.

Clear the codes, then start the car. Check for cylinder misfire codes. Reseat any cylinders that are still misfiring. Repeat until it’s clean.

Note:
1. Don’t use dielectric grease. It causes the coils to lift.
2. Do use DeOxit on the connector contacts if you’re worried.
3. The plastic hold downs that bolt to the head don’t guarantee that the coil is seated.