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Bad Coil Packs? What are the symptoms

104K views 25 replies 12 participants last post by  icefox 
#1 ·
So I was driving my car tonight kinda hard (not that bad) on the highway, my Rpms were in the 3500-4000 range for a good amount of time.. After i get off the highway the car is running rough, sounds like a wrx. I know people on this site say a car sounding like a WRX is most likely the coil packs.
My question is... What causes the coil packs to go? Is it just coincidence that they went after I was getting on the car a little? And how can I determine which coil pack out of the four is the bad one or one(s).
 
#9 ·
Re: Bad Coil Packs? What are the symptoms (icefox)

Typically your engine will be running rough. You usually can head/feel it missing along with degraded performance. Your CEL light sometimes will flash indicating a misfire issue.
The easiest way to determain which coil pack is bad is using VAG-COM.
Without VAG-COM you can remove each coil pack and look for stress/ burn marks. If none of them show physical signs of damage, pull and read the spark plugs.
 
#10 ·
if you dont have a VAG-COM, just a generic OBDII scanner and you get a misfire in a cylinder, swap the corresponding coil with another one and see if the CEL jumps with it.
either way, there are a thousand reasons why you could be running lean, but relatively few places that could be the cause of it. its not getting burned, so it definitely sounds like something with the plugs or the like.
 
#11 ·
Re: (Custom158)

is it bad to drive with bad coil packs? I only ask because I have other coil packs at my parents house, and I wanted to put those in and see if i fix the problem, also my friend with a vag com live up near my parents. Its about a 45 min drive. What do you say?
 
#13 ·
Re: (ratbox20v)

I pulled them and they all seemed to be alright, the only difference I seemed to notice with one of them was all the way inside on the metal that actually touches the spark plug was either black or brown, either way I couldnt see it, where was on the other 3 it was clearly visible.
 
#14 ·
Re: (icefox)

Quote, originally posted by icefox »
I pulled them and they all seemed to be alright, the only difference I seemed to notice with one of them was all the way inside on the metal that actually touches the spark plug was either black or brown, either way I couldnt see it, where was on the other 3 it was clearly visible.

Its like that skit on Seasame street - "Which one of these is not like the others?"
Sounds to me like you've narrowed down which one is bad.
 
#18 ·
Re: Bad Coil Packs? What are the symptoms (icefox)

Quote, originally posted by icefox »
My question is... What causes the coil packs to go? Is it just coincidence that they went after I was getting on the car a little? And how can I determine which coil pack out of the four is the bad one or one(s).

Coil packs most often go if you are driving a 1.8T

Seriously, I've had a number go on me, and it's normally under high acceleration. I kept replacing one here and there with the Bremi "R" revision (AWW engine), or whatever was the newest at the time. Problem was they kept poping out and going bad. Finally, when two went bad at the same time, I changed all 4 to the Hitachi "E" revision normally, AWD engine) and bolted them onto the valve cover. I haven't had an issue since then.
 
#23 ·
Re: Bad Coil Packs? What are the symptoms (icefox)

I'm certain this is not a VW approved diagnostic technique, but it works. With the engine idling, pull a coil off the sparkplug. If it is good, you will hear a pop, pop, pop sound of the spark on each ignition cycle. No pop= bad coil.
 
#25 ·
Re: Bad Coil Packs? What are the symptoms (r0ach)

Quote, originally posted by r0ach »
Pull them all and if one is bad the metal may appear to have a brownish tint. (I have no idea why that happens but it does)

that's not necessarily true in all cases. i had two of the brand new version "R" go out on me after 2 months! they looked brand new!! http://****************.com/smile/emthdown.gif http://****************.com/smile/emthdown.gif

Edit:
Please replace them all with Hitachi bolt-down coilpacks found on http://www.ecstuning.com and save whatever good coils you have in your trunk http://****************.com/smile/emthup.gif


Modified by RvGrnGTI at 9:19 PM 1-22-2008
 
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