Question about coils going bad

04mazdaspeed · 07-28-2018, 12:10 AM

Hey guys. Just in the past few weeks, I had a misfire on 5 and 6 and it turned out to be my Delphi coils with 1k miles on them took a crap. Replaced them and all was fine until tonight again, it misfired and now is saying cylinder 6. I have a extra coil that im going to install in the morning to see if that fixes it again. Why are these coils going bad so fast? Im custom tuned on e30. I thought the Delphi coils were suppose to be newer and better? Anyone using precision raceworks coil set for the N55? Im willing to invest the money if they can be more reliable that the stock coils.

The Wind Breezes · 07-28-2018, 02:10 AM

What is wrong with the stock coils, exactly? And for that matter, how do you know your misfire is down to a bad coil? These things are way hardier than people give them credit for. When one actually blows, you'll know it. And they have WAY more than enough juice to ignite anything you're gonna toss into a stock motor.

04mazdaspeed · 07-28-2018, 02:31 AM

Well when I had the misfire the first time, I replaced those two coils and the problem went away. It will only misfire under heavy load and high rpm. If I am easing into the throttle its perfectly fine. Mash the gas at 3k and it breaks up as soon as boost hits.

juld0zer · 07-29-2018, 06:30 AM

Are you sure you are properly engaging the connector to the coil? I pre-engage the connector to the latch so I know they are locked together, then guide the connector all the way in whilst lowering the latch. Sometimes the connector will 'latch' and also look latched enough but it isn't. Also keep an eye out for the latch popping out of the coil hinge.

litebulb · 08-01-2018, 01:10 AM

FYI, if you are looking at switching I was told Endor coils newer/better than the Delphi. I replaced the full set earlier this month and they have been going strong on OTS MHL stage 2+

04mazdaspeed · 08-01-2018, 08:01 AM

Update. I replaced #6 with a new bosch coil and problem completely went away. Maybe just a bad batch? Either way I bought a few extra just in case..lol

07-28-2018, 12:10 AM	#1
04mazdaspeed Private First Class 61 Rep 144 Posts Drives: 2011 135i DCT Join Date: May 2017 Location: Chicago, IL iTrader: (0)	Question about coils going bad Hey guys. Just in the past few weeks, I had a misfire on 5 and 6 and it turned out to be my Delphi coils with 1k miles on them took a crap. Replaced them and all was fine until tonight again, it misfired and now is saying cylinder 6. I have a extra coil that im going to install in the morning to see if that fixes it again. Why are these coils going bad so fast? Im custom tuned on e30. I thought the Delphi coils were suppose to be newer and better? Anyone using precision raceworks coil set for the N55? Im willing to invest the money if they can be more reliable that the stock coils. __________________ 2011 135i DCT, 33k miles FBO on custom e30 tune
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07-28-2018, 02:10 AM	#2
The Wind Breezes Lieutenant Colonel 912 Rep 1,850 Posts Drives: 135i N55 DCT Join Date: Apr 2015 Location: USA iTrader: (0)	What is wrong with the stock coils, exactly? And for that matter, how do you know your misfire is down to a bad coil? These things are way hardier than people give them credit for. When one actually blows, you'll know it. And they have WAY more than enough juice to ignite anything you're gonna toss into a stock motor.
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07-28-2018, 02:31 AM	#3
04mazdaspeed Private First Class 61 Rep 144 Posts Drives: 2011 135i DCT Join Date: May 2017 Location: Chicago, IL iTrader: (0)	Well when I had the misfire the first time, I replaced those two coils and the problem went away. It will only misfire under heavy load and high rpm. If I am easing into the throttle its perfectly fine. Mash the gas at 3k and it breaks up as soon as boost hits. __________________ 2011 135i DCT, 33k miles FBO on custom e30 tune
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07-29-2018, 06:30 AM	#4
juld0zer Lieutenant Colonel 480 Rep 1,600 Posts Drives: Prev 135i 7DCT, Now 130i 6sp Join Date: Jul 2016 Location: 2153 iTrader: (0)	Are you sure you are properly engaging the connector to the coil? I pre-engage the connector to the latch so I know they are locked together, then guide the connector all the way in whilst lowering the latch. Sometimes the connector will 'latch' and also look latched enough but it isn't. Also keep an eye out for the latch popping out of the coil hinge.
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08-01-2018, 01:10 AM	#5
litebulb Captain 68 Rep 627 Posts Drives: '09 E88 135i M-Sport/6MT/SGM Join Date: Feb 2011 Location: Vancouver iTrader: (3) Garage List 2009 BMW 135i Cabri ... [10.00]	FYI, if you are looking at switching I was told Endor coils newer/better than the Delphi. I replaced the full set earlier this month and they have been going strong on OTS MHL stage 2+ __________________ \| Dinan S2=>MHD \| e46 M3 trans mounts \| Dinan CF CAI \| ER CP \| HKS SSQV4 BOV \| RB PCV Valve \| VRSF DP \| N55 MP \| BMW PE \| OC \| VRSF 7" FMIC \| UUC Evo3 SSK \| EBC GD Sport Rotors \| EBC Redstuff \| TRW F+R \| \| Whiteline KDT918 \| H&R Front Sway \| BMWP 313 \| MPSS 225/255 \| Scopione CF Rear Diffuser \| iCarbon CF Rear Spoiler \| P3 v2.1 Gauge \| Interior LED Retrofit \|
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08-01-2018, 08:01 AM	#6
04mazdaspeed Private First Class 61 Rep 144 Posts Drives: 2011 135i DCT Join Date: May 2017 Location: Chicago, IL iTrader: (0)	Update. I replaced #6 with a new bosch coil and problem completely went away. Maybe just a bad batch? Either way I bought a few extra just in case..lol __________________ 2011 135i DCT, 33k miles FBO on custom e30 tune
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