Slight Misfire

rominun · 04-10-2017, 11:14 PM

So i bought a 2008 BMW 135i a couple months back. I just changed my spark plugs and cleaned the intake valves. Im having a slight misfire at idle (no codes) and when im tuned, the misfire happens after multiple WOT runs. I got cylinder one misfire, so i flip flopped that coil with #2. I tried to replicate the problem so it can throw a code, but it doesnt want too. However the misfire at idle is still the same!!

Some of you know that i swapped my motor due to a spun bearing. When i swapped motors, i transferred all the components to the new one. This misfire has been happening on both motors, so it has to be something related to fuel, air, or my ignition coils. How do i know if it is my injectors. Maybe they arent index 10+ or arent even coded. Ive been stumbled upon this more months. Please help. BTW i just ordered one brand new bosch coil to see if it will help me track down a bad coil.

rominun · 04-10-2017, 11:24 PM

forgot to mention that i have 5 index 8 injectors and 1 index 7 injector.

ianc · 04-11-2017, 12:32 AM

Quote:

the misfire happens after multiple WOT runs

Sounds like coils; they heat up after hard runs. Mileage?

Unless you're strapped for cash, think about coils and injectors. They're cheap (relatively) now...

ianc

rominun · 04-11-2017, 12:33 AM

Quote:

Originally Posted by ianc

Quote:

the misfire happens after multiple WOT runs

Sounds like coils; they heat up after hard runs. Mileage?

Unless you're strapped for cash, think about coils and injectors. They're cheap (relatively) now...

ianc

not sure about the mileage on the injectors or coils. i'm thinking it's the coils, i bought a new one and i'm going to replace it with cyl 1 because that's where the misfire first came from.

Dackelone · 04-11-2017, 04:33 AM

Did you use BMW dealer bought plugs? They say "BMW-Bosch" on the plugs. Some guys experience misfires with aftermarket "Bosch" plugs. Could be a bad coil or fuel injector.

Coils don't last that long... if you are around 70K I would just replace all six coils.

rominun · 04-11-2017, 10:00 AM

Quote:

Originally Posted by Dackelone

Did you use BMW dealer bought plugs? They say "BMW-Bosch" on the plugs. Some guys experience misfires with aftermarket "Bosch" plugs. Could be a bad coil or fuel injector.

Coils don't last that long... if you are around 70K I would just replace all six coils.

yeah ill probably end up swapping the coils

Stewy_604 · 04-11-2017, 03:50 PM

+1 for the coils. What gap are the plugs?

rominun · 04-11-2017, 03:50 PM

Quote:

Originally Posted by Stewy_604

+1 for the coils. What gap are the plugs?

not sure. i'm just popped them in when i bought them

rominun · 04-13-2017, 01:09 AM

Quote:

Originally Posted by Dackelone

Did you use BMW dealer bought plugs? They say "BMW-Bosch" on the plugs. Some guys experience misfires with aftermarket "Bosch" plugs. Could be a bad coil or fuel injector.

Coils don't last that long... if you are around 70K I would just replace all six coils.

yeah ill probably end up swapping the coils

Jeff@TopGearSolutions · 04-13-2017, 09:37 AM

As another member suggested, if you are strapped for cash you can try and budget doing a coil or injector here and there but I'd sooner tell you to replace all 6 injectors and 6 coils.

Those old injectors especially the index 7 and 8 were one of the worst revisions.

Your car will be performing and running in top top shape with all new injectors and coils. Highly recommend if you can afford it.

rominun · 04-13-2017, 09:39 AM

Quote:

Originally Posted by Jeff@TopGearSolutions

As another member suggested, if you are strapped for cash you can try and budget doing a coil or injector here and there but I'd sooner tell you to replace all 6 injectors and 6 coils.

Those old injectors especially the index 7 and 8 were one of the worst revisions.

Your car will be performing and running in top top shape with all new injectors and coils. Highly recommend if you can afford it.

i thought so. my friend just totaled his 135i so i think he's letting me have any of his parts as long as i swap them out with mine.

rominun · 04-13-2017, 08:52 PM

So i think i fixed the issue. Friends car got totaled and gave me me brand new oem coils and index 12 injectors. car runs better than before but ill let you guys know a couple days from now.

Mandinca · 11-27-2017, 10:54 AM

Quote:

Originally Posted by rominun

So i think i fixed the issue. Friends car got totaled and gave me me brand new oem coils and index 12 injectors. car runs better than before but ill let you guys know a couple days from now.

I'm having a similar issue - did coils and injectors fix it permanently ?

rominun · 11-27-2017, 11:13 AM

Quote:

Originally Posted by Mandinca

Quote:

Originally Posted by rominun

So i think i fixed the issue. Friends car got totaled and gave me me brand new oem coils and index 12 injectors. car runs better than before but ill let you guys know a couple days from now.

I'm having a similar issue - did coils and injectors fix it permanently ?

yeah, i had a faulty injector. i would start with replacing your plugs and coils. if those dont fix it then its most likely your injectors.

04-10-2017, 11:14 PM	#1
rominun Banned 171 Rep 615 Posts Drives: 2008 Bmw 135i Join Date: Sep 2016 Location: So-Cal iTrader: (0)	Slight Misfire So i bought a 2008 BMW 135i a couple months back. I just changed my spark plugs and cleaned the intake valves. Im having a slight misfire at idle (no codes) and when im tuned, the misfire happens after multiple WOT runs. I got cylinder one misfire, so i flip flopped that coil with #2. I tried to replicate the problem so it can throw a code, but it doesnt want too. However the misfire at idle is still the same!! Some of you know that i swapped my motor due to a spun bearing. When i swapped motors, i transferred all the components to the new one. This misfire has been happening on both motors, so it has to be something related to fuel, air, or my ignition coils. How do i know if it is my injectors. Maybe they arent index 10+ or arent even coded. Ive been stumbled upon this more months. Please help. BTW i just ordered one brand new bosch coil to see if it will help me track down a bad coil.
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04-11-2017, 04:33 AM	#5
Dackelone European Editor 10604 Rep 22,992 Posts Drives: N54 e82 Join Date: Feb 2010 Location: Bayern, Germany iTrader: (1)	Did you use BMW dealer bought plugs? They say "BMW-Bosch" on the plugs. Some guys experience misfires with aftermarket "Bosch" plugs. Could be a bad coil or fuel injector. Coils don't last that long... if you are around 70K I would just replace all six coils. __________________ Dackel's European Delivery Museum Guide
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04-11-2017, 03:50 PM	#7
Stewy_604 First Lieutenant 77 Rep 310 Posts Drives: 2011 E82 135i M-Sport Join Date: Aug 2015 Location: Vancouver, B.C. iTrader: (0)	+1 for the coils. What gap are the plugs? __________________ 2011 BMW 135i M Sport Space Grey - BMS JB4, VRSF 3.5" catless DP, Berk exhaust, BMS intake, ER CP, Eibach Pro-Kit, H&R spacers, black kidneys, Blacklines, LUX angel eyes 2014 BMW X5 xDrive 35d M Sport Mineral White - MPBK w/ F85 rotors & Carbotech pads, ACS Springs/Links, iND reflector deletes, iND black roundels, MP black kidneys, M50D grille inserts 2007 Suzuki GSX-R 750 - too much to list
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04-13-2017, 09:37 AM	#10
Jeff@TopGearSolutions 3441 Rep 79,211 Posts Drives: C6 Z06, 09 335i, 10 335xi Join Date: Dec 2008 Location: www.TopGearSolutions.com iTrader: (37)	As another member suggested, if you are strapped for cash you can try and budget doing a coil or injector here and there but I'd sooner tell you to replace all 6 injectors and 6 coils. Those old injectors especially the index 7 and 8 were one of the worst revisions. Your car will be performing and running in top top shape with all new injectors and coils. Highly recommend if you can afford it.
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04-13-2017, 08:52 PM	#12
rominun Banned 171 Rep 615 Posts Drives: 2008 Bmw 135i Join Date: Sep 2016 Location: So-Cal iTrader: (0)	update So i think i fixed the issue. Friends car got totaled and gave me me brand new oem coils and index 12 injectors. car runs better than before but ill let you guys know a couple days from now.
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04-10-2017, 11:24 PM	#2
rominun Banned 171 Rep 615 Posts Drives: 2008 Bmw 135i Join Date: Sep 2016 Location: So-Cal iTrader: (0)	forgot to mention that i have 5 index 8 injectors and 1 index 7 injector.
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