Possible fuel injector issue?

renesis27 · 11-26-2012, 08:56 PM

Put new plugs in about a month ago and started to misfire...swapped coils and still misfiring from time to time in cylinder 5. Weird thing is that it only misfires when I opening her up and when its boosting towards 15lbs...if I keep it to 10lbs its fine. I am going to replaced that plug tomorrow thinking maybe its the plug that is fouled and was bad from the start...my other thought is that if it still does it with the new plug, then it has to be injectors right? Can it be possible that my injector is already bad? I have an 08 with only 50,600 miles on her...just seems strange no misfire when hit around 10, but when you open her up more than that..boom misfire and then it goes away once you turn her off and on again...any thought?

Dackelone · 11-26-2012, 09:17 PM

Did you use BMW bought plugs? See my Spark Plug DYI for why. Aftermarket plugs are known to cause issues.

IF your plugs are good, then it can be coils or injectors.

Tee-Dub · 11-26-2012, 09:36 PM

My car had 3 injectors replaced under a recall, all before hitting 35k miles.

renesis27 · 11-26-2012, 10:04 PM

I don't think it's the coils because I've swapped them around and it only occurs in cylinder 5. I bought a oem BMW plug and will install it tomorrow so ill keep everyone posted. My guess is if that doesn't fix it it has to be an injector but idk how to change that myself

Fed P · 11-27-2012, 10:31 AM

It's not too hard actually. You unscrew the fuel pipe going from the main rail to the injector (careful, it can spray fuel, especially if you haven't let it all cool), unplug the electric cable that supplies the injector, unscrew a plate holding down the injectors (3 plates, each one holds 2 injectors, 1-2, 3-4, 5-6), pull the injector up and out, replace with new. If going with new it's much simpler and you need less special tools, because if replacing existing then you need to do a bit more work with the seal on the end of the injector which has to be replaced if you don't reinstall the injector within 5 minutes of taking it out (supposedly the sealing ring swells up).

I would do this on a cold car and I would unplug the battery just in case, it's never a bad idea IMO.

However, since your issue started after changing the plugs, it's probably not a coincidence!

renesis27 · 11-28-2012, 08:20 PM

So quick update...I replaced the plug and beat the shit out of my car when it was warmed to proper temps and didn't misfire yet. Hopefully that fixed it. My other question is that the car feels sluggish and I'm not sure if it is due to the cold weather here in Philly right now...about 35 degrees. Also, anyone know any other possible issue with idle not being as smooth as it should be? I replaced plugs already and have replaced the valve cover gasket. Don't know if this has anything to do with it, but I was watching my spark advance and it was jumping from -3 to 2 and wasn't sure if that was normal or not..Thanks for the help guys!

slow35i · 11-30-2012, 09:00 AM

Have your intake ports carbon blasted @ 50k I'm suprised you lasted this long , we've had to perform carbon blasting on cars as low as 15k miles ,also perform a fuel injection flush with BMW FUEL SYSTEM concentrate (blueish/greenish bottle )

slow35i · 11-30-2012, 09:02 AM

Were starting to recommend it as a service interval of every 30k

Dackelone · 11-30-2012, 09:17 AM

Quote:

Originally Posted by renesis27

So quick update...I replaced the plug and beat the shit out of my car when it was warmed to proper temps and didn't misfire yet. Hopefully that fixed it. My other question is that the car feels sluggish and I'm not sure if it is due to the cold weather here in Philly right now...about 35 degrees. Also, anyone know any other possible issue with idle not being as smooth as it should be? I replaced plugs already and have replaced the valve cover gasket. Don't know if this has anything to do with it, but I was watching my spark advance and it was jumping from -3 to 2 and wasn't sure if that was normal or not..Thanks for the help guys!

Any oil leaks, like a valve cover gasket(VCG) will also cause a vacuum leak. Vacuum leaks will cause a rough idle. Maybe your VCG is still leaking. ?

It could also be the winter blends of fuel in your area. Maybe change fuel brands. ?

Sounds like the spark plugs were your issue.

Tee-Dub · 11-30-2012, 10:11 PM

If you were at 50k on original plugs it was past time to replace them all, especially if you're tuned. I've heard guys recommend every 25k on a tuned car. BMW says 45k as a stock recommendation. Running a tune will show weaknesses in your ignition system from what I've been reading.

renesis27 · 12-02-2012, 06:35 PM

I've changed the plugs..guess the one new plug I bought was foul and causing issues. The car is boosting as high as 15 lbs...could be the cold weather. I don't know what other gas to use. I only go to shell or sunoco and ONLY use 93. SLOW35I where do I get this fuel system concentrate? and do you work at a dealership or something that you are saying WE are starting to recommend it? Thanks guys!

11-26-2012, 08:56 PM	#1
renesis27 Private First Class 29 Rep 143 Posts Drives: '08 135i Coupe Black Saphire Join Date: Apr 2012 Location: Philadelphia iTrader: (0)	Possible fuel injector issue? Put new plugs in about a month ago and started to misfire...swapped coils and still misfiring from time to time in cylinder 5. Weird thing is that it only misfires when I opening her up and when its boosting towards 15lbs...if I keep it to 10lbs its fine. I am going to replaced that plug tomorrow thinking maybe its the plug that is fouled and was bad from the start...my other thought is that if it still does it with the new plug, then it has to be injectors right? Can it be possible that my injector is already bad? I have an 08 with only 50,600 miles on her...just seems strange no misfire when hit around 10, but when you open her up more than that..boom misfire and then it goes away once you turn her off and on again...any thought?
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11-26-2012, 09:17 PM	#2
Dackelone European Editor 10528 Rep 22,992 Posts Drives: N54 e82 Join Date: Feb 2010 Location: Bayern, Germany iTrader: (1)	Did you use BMW bought plugs? See my Spark Plug DYI for why. Aftermarket plugs are known to cause issues. IF your plugs are good, then it can be coils or injectors. __________________ Dackel's European Delivery Museum Guide
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11-26-2012, 09:36 PM	#3
Tee-Dub Captain 35 Rep 753 Posts Drives: 2008 135i Join Date: May 2009 Location: Vancouver, WA iTrader: (9)	My car had 3 injectors replaced under a recall, all before hitting 35k miles.
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11-26-2012, 10:04 PM	#4
renesis27 Private First Class 29 Rep 143 Posts Drives: '08 135i Coupe Black Saphire Join Date: Apr 2012 Location: Philadelphia iTrader: (0)	I don't think it's the coils because I've swapped them around and it only occurs in cylinder 5. I bought a oem BMW plug and will install it tomorrow so ill keep everyone posted. My guess is if that doesn't fix it it has to be an injector but idk how to change that myself
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11-27-2012, 10:31 AM	#5
Fed P Private First Class 23 Rep 111 Posts Drives: 135i Join Date: Mar 2012 Location: Russia iTrader: (0)	It's not too hard actually. You unscrew the fuel pipe going from the main rail to the injector (careful, it can spray fuel, especially if you haven't let it all cool), unplug the electric cable that supplies the injector, unscrew a plate holding down the injectors (3 plates, each one holds 2 injectors, 1-2, 3-4, 5-6), pull the injector up and out, replace with new. If going with new it's much simpler and you need less special tools, because if replacing existing then you need to do a bit more work with the seal on the end of the injector which has to be replaced if you don't reinstall the injector within 5 minutes of taking it out (supposedly the sealing ring swells up). I would do this on a cold car and I would unplug the battery just in case, it's never a bad idea IMO. However, since your issue started after changing the plugs, it's probably not a coincidence!
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11-28-2012, 08:20 PM	#6
renesis27 Private First Class 29 Rep 143 Posts Drives: '08 135i Coupe Black Saphire Join Date: Apr 2012 Location: Philadelphia iTrader: (0)	So quick update...I replaced the plug and beat the shit out of my car when it was warmed to proper temps and didn't misfire yet. Hopefully that fixed it. My other question is that the car feels sluggish and I'm not sure if it is due to the cold weather here in Philly right now...about 35 degrees. Also, anyone know any other possible issue with idle not being as smooth as it should be? I replaced plugs already and have replaced the valve cover gasket. Don't know if this has anything to do with it, but I was watching my spark advance and it was jumping from -3 to 2 and wasn't sure if that was normal or not..Thanks for the help guys!
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11-30-2012, 09:00 AM	#7
slow35i Enlisted Member 3 Rep 48 Posts Drives: 13' glacier silver 328xi Join Date: Oct 2012 Location: Grandview, WA iTrader: (0)	Have your intake ports carbon blasted @ 50k I'm suprised you lasted this long , we've had to perform carbon blasting on cars as low as 15k miles ,also perform a fuel injection flush with BMW FUEL SYSTEM concentrate (blueish/greenish bottle )
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11-30-2012, 09:02 AM	#8
slow35i Enlisted Member 3 Rep 48 Posts Drives: 13' glacier silver 328xi Join Date: Oct 2012 Location: Grandview, WA iTrader: (0)	Were starting to recommend it as a service interval of every 30k
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11-30-2012, 10:11 PM	#10
Tee-Dub Captain 35 Rep 753 Posts Drives: 2008 135i Join Date: May 2009 Location: Vancouver, WA iTrader: (9)	If you were at 50k on original plugs it was past time to replace them all, especially if you're tuned. I've heard guys recommend every 25k on a tuned car. BMW says 45k as a stock recommendation. Running a tune will show weaknesses in your ignition system from what I've been reading.
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12-02-2012, 06:35 PM	#11
renesis27 Private First Class 29 Rep 143 Posts Drives: '08 135i Coupe Black Saphire Join Date: Apr 2012 Location: Philadelphia iTrader: (0)	I've changed the plugs..guess the one new plug I bought was foul and causing issues. The car is boosting as high as 15 lbs...could be the cold weather. I don't know what other gas to use. I only go to shell or sunoco and ONLY use 93. SLOW35I where do I get this fuel system concentrate? and do you work at a dealership or something that you are saying WE are starting to recommend it? Thanks guys!
	Appreciate 0 Quote