Quote:
Originally Posted by MohiAli
Hi, Please help! read all the pointers and followed them.
I had engine management light come up whilst driving one day.
Had it diagnosed. Misfire Cylinder 2&3 P302 and P303.
To eliminate the error, changed the coils around to test swapped 1 with 2 and 3 with 4 but fault remained in the same cylinders 2&3.
Changed the spark plugs around, again fault remained on cylinder 2 & 3.
Got the garage to then swap injectors around, fault only came up only on Cylinder 3 so to be safe had all 4 injectors changed upgraded to Index 9 from Index 7. Fault has now returned to Cylinder 2 and 3! After so much time, money and effort back to square one.
Car now in limp mode and management light come up as fast as you clear it.
I did notice however, when engine on and i disconnect the 2nd and 3rd coil (1 at a time) the engine carries on running but if i do the same with 1 and 4 engine almost cuts out. Not sure if that means anything to anyone.
Should I change all spark plugs and coils also or would that be a waste of time and funds?
Please can someone assist a fellow Bimmer driver in distress??
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Your process of elimination was correct! You switched the coils and plugs around but to no avail but when you switched the injectors you had some success. So it is most likely a faulty injector here based on what you posted. But it sounds like you bought "used" index 9 injectors here, So I have a few questions:
1. When you bought the used injectors, did you replace the expanding o-ring and the decoupling element? That could cause an issue where the injector is not seated correctly.
2. IF you did successfully replace those elements of the injector the last things are, was it installed in a timely manner? (After the self expanding o-ring is exposed [taking off the cap that comes with the injector], it starts to expand. So was the injectors replaced pretty quickly?
3. Last thing, if it was installed correctly, WAS IT CODED??? After installation the injectors has to be coded to new values. After coding, delete all errors and try starting the car.
4. If you did everything here and still got errors, this is the extent of my knowledge with this subject, sorry, LOL.
Quote:
Originally Posted by plilp
I have an -08 E91 with the n53 3liter motor and I'm having similar misfire issues in cylinder 3. Spark plugs (NGK) and ignition coils (Bosch) have been changed but it's still happening. After changing the coils the misfire didn't happen for 2 days but then reappeared. I have ordered new injectors (index 11) but I'm afraid it won't solve the issue... my symptoms in detail:
After starting the car there's no issues. I can drive for a good 15-20min before the symptoms appear. The check engine light will go on and the engine starts running roughly, rpm will start to fluctuate as well. When accelerating there's no power and the car noticeably shakes when slowly picking up speed. Idle is then also rough and rpm keeps fluctuating. Issue will not solve while the engine is hot, even if the car is turned off and back on the symptoms start immediately. Then the next day or after properly cooling down, the symptoms are gone again. As mentioned the only consistent error code I've received from the engine is P0303.
I believe the injectors are still the original ones or at least very old. I haven't checked myself. I used a petrol system cleaner, the kind you pour in the gas tank, and I feel like it improved the situation slightly, so I'm hopeful that replacing the injectors will fix the issue but still afraid it doesn't.
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Please refer to my response to the other quote on this message, I believe you are going through what he's going through. So when you install the new injectors please go through the checklist above to avoid any issues. If you replaced the plugs and coils with OEM spec parts and you are stock, you shouldnt worry about "gapping plugs". Hopefully this helps, Good luck friends.
Video Reference to how to properly change injectors (cred: Jake Spence):