Coil pack test.
08-30-2005, 02:42 PM
#1
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Thread Starter
Join Date: Jul 2005
Posts: 32
Coil pack test.
Hello all. This my first thread on this board but it should help some people.
I just bought a 95 Maxima about a month ago and noticed that it had a weird miss at stoplights and stopsigns. It even hesitated slightly while accelerating. The miss was very bad. It was to the point it was pissing me off and I didn't want to drive it. Just like most members I assumed it needed a good ole tune up until I read some interesting things on this board.
To make a long story short, last weekend I decided to somehow test these things so I could fix the problem.
On my initial attempt I used a multimeter to test them and I got no difference in the readings. None at all. Then I realized that the engine only missed when the car was fully warmed up, in drive, with the brakes held. Do you see where i'm going with this?
So, with that in mind I decided to drive the car around until it actually started to miss(it didn't take long). I then drove back home, stopped the car, left it in drive, pulled the e-brake and put a brick under the front tire. Doing this similates exactly what the car is doing at a stopsign or stoplight so i figured that would be a good condition to test under.
Now, I opened the hood and watched the engine until it started missing(it didnt' take long). It was easy to see because it engine rocked nicely when it happened.
HERE IS HOW TO TEST!!!!!
What I did was created and additional missfire to find this sucker. I unlplugged each coil one by one by one... Most people know on a perfectly well running engine if you pull any spark plug wire it will create a missfire. What I did was used this fact to find the bad coil. If you pull the bad coil the engine will only missfire on that cylinder. If you pull the good coil the engine will missfire from the good coil you just unplugged and the bad one that is still plugged up. In other words it will missfire on two cylinders instead of one.
When I did this there was only one coil that I unplugged and the car only missed on one cylinder. THAT WAS THE BAD COIL.
Whey you unplug a coil you will need to watch how the engine is running for a minute or so. I did this test 3 times and every time it missed once when the front bank middle coil was unplugged. I went to a junkyard and had a buddy pull all three front bank coils off a maxima for free. I thought surely one of them was good. The first one I put in was a good coil. The car hasn't missed since and it's been almost 2 weeks. Very smooth under acceleration. I set in my driveway one day in drive(D) with the brakes held for at least 5 minutes one day and not one miss. Not one.
Any questions? Let me know. I will edit later with a simple version instead of the whole story.
WES
I just bought a 95 Maxima about a month ago and noticed that it had a weird miss at stoplights and stopsigns. It even hesitated slightly while accelerating. The miss was very bad. It was to the point it was pissing me off and I didn't want to drive it. Just like most members I assumed it needed a good ole tune up until I read some interesting things on this board.
To make a long story short, last weekend I decided to somehow test these things so I could fix the problem.
On my initial attempt I used a multimeter to test them and I got no difference in the readings. None at all. Then I realized that the engine only missed when the car was fully warmed up, in drive, with the brakes held. Do you see where i'm going with this?
So, with that in mind I decided to drive the car around until it actually started to miss(it didn't take long). I then drove back home, stopped the car, left it in drive, pulled the e-brake and put a brick under the front tire. Doing this similates exactly what the car is doing at a stopsign or stoplight so i figured that would be a good condition to test under.
Now, I opened the hood and watched the engine until it started missing(it didnt' take long). It was easy to see because it engine rocked nicely when it happened.
HERE IS HOW TO TEST!!!!!
What I did was created and additional missfire to find this sucker. I unlplugged each coil one by one by one... Most people know on a perfectly well running engine if you pull any spark plug wire it will create a missfire. What I did was used this fact to find the bad coil. If you pull the bad coil the engine will only missfire on that cylinder. If you pull the good coil the engine will missfire from the good coil you just unplugged and the bad one that is still plugged up. In other words it will missfire on two cylinders instead of one.
When I did this there was only one coil that I unplugged and the car only missed on one cylinder. THAT WAS THE BAD COIL.
Whey you unplug a coil you will need to watch how the engine is running for a minute or so. I did this test 3 times and every time it missed once when the front bank middle coil was unplugged. I went to a junkyard and had a buddy pull all three front bank coils off a maxima for free. I thought surely one of them was good. The first one I put in was a good coil. The car hasn't missed since and it's been almost 2 weeks. Very smooth under acceleration. I set in my driveway one day in drive(D) with the brakes held for at least 5 minutes one day and not one miss. Not one.
Any questions? Let me know. I will edit later with a simple version instead of the whole story.
WES
08-30-2005, 02:46 PM
#2
This is not revolutionary - it's the recommended way to find a bad coil, i.e. if you are having misfires, pull coils until you find one that doesn't change the way the engine is running. Once you pull a coil that doesn't change the way the engine is running, you have found the culprit.
To further validate your test, swap coils from a "properly" firing cylinder with the bad coil, and see if the misfire moves to the new cylinder (i.e. the cylinder you just put the bad coil on).
Glad you got your problem solved
To further validate your test, swap coils from a "properly" firing cylinder with the bad coil, and see if the misfire moves to the new cylinder (i.e. the cylinder you just put the bad coil on).
Glad you got your problem solved
08-30-2005, 03:52 PM
#3
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Thread Starter
Join Date: Jul 2005
Posts: 32
Originally Posted by njmodi
This is not revolutionary - it's the recommended way to find a bad coil, i.e. if you are having misfires, pull coils until you find one that doesn't change the way the engine is running. Once you pull a coil that doesn't change the way the engine is running, you have found the culprit.
To further validate your test, swap coils from a "properly" firing cylinder with the bad coil, and see if the misfire moves to the new cylinder (i.e. the cylinder you just put the bad coil on).
Glad you got your problem solved
To further validate your test, swap coils from a "properly" firing cylinder with the bad coil, and see if the misfire moves to the new cylinder (i.e. the cylinder you just put the bad coil on).
Glad you got your problem solved
Never said it was. I just never read it in all my searching on the site.
Thanks.
WES
08-30-2005, 06:40 PM
#4
Member who somehow became The President of The SE-L Club
iTrader: (19)
Join Date: Jun 2001
Posts: 16,033
Originally Posted by maxultra
I set in my driveway one day in drive(D) with the brakes held for at least 5 minutes one day
The excessive heat you created with the torque converter will completely break down your transmission fluid. If I were you, I'd get the tranny fluid changed after that stunt.
08-30-2005, 09:06 PM
#5
So everytime Im at a longer red stop-light, in crazy heavy traffic or waiting for the train to finish passing, I should switch it to Neutral, or Park ? Is that what your recommending ?
(This is a serious question)
(This is a serious question)
08-30-2005, 10:19 PM
#6
Guest
Posts: n/a
Originally Posted by goldtooth
So everytime Im at a longer red stop-light, in crazy heavy traffic or waiting for the train to finish passing, I should switch it to Neutral, or Park ? Is that what your recommending ?
(This is a serious question)
(This is a serious question)
08-31-2005, 12:29 PM
#7
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Thread Starter
Join Date: Jul 2005
Posts: 32
Originally Posted by njmaxseltd
Excellent way to burn your transmission fluid. The excessive heat you created with the torque converter will completely break down your transmission fluid. If I were you, I'd get the tranny fluid changed after that stunt.
The excessive heat you created with the torque converter will completely break down your transmission fluid. If I were you, I'd get the tranny fluid changed after that stunt.Dude you must change your fluid a lot then if that's the case. I have set longer than that at 4 way stoplights during lunch hour rush.
I guess I better go change my tranny fluid. Yeah right.
WES
08-31-2005, 02:38 PM
#8
Originally Posted by njmaxseltd
Excellent way to burn your transmission fluid. The excessive heat you created with the torque converter will completely break down your transmission fluid. If I were you, I'd get the tranny fluid changed after that stunt.
The excessive heat you created with the torque converter will completely break down your transmission fluid. If I were you, I'd get the tranny fluid changed after that stunt.
08-31-2005, 03:12 PM
#9
Newbie - Just Registered
Join Date: Aug 2005
Posts: 2
Pardon My Noobness... But your description your car's symptoms are identical to those of my recently purchased Max. I called the local dealer today and they want $100 to do a diagnostic with a scope.
After reading this site I am sure I am experiencing this infamous "Coil" issue. Just a quick question about your procedure above...
I understand the logic but can I just remove the cover and start unplugging coils by hand with the engine running? Are there any safety concerns doing this?
Just Curious..
Thanks. I think you may have saved me $100.
After reading this site I am sure I am experiencing this infamous "Coil" issue. Just a quick question about your procedure above...
I understand the logic but can I just remove the cover and start unplugging coils by hand with the engine running? Are there any safety concerns doing this?
Just Curious..
Thanks. I think you may have saved me $100.
08-31-2005, 06:55 PM
#10
Senior Member
Join Date: Dec 2003
Posts: 994
1- that method will not always work..
2- a bad coil pack creates a mis-fire, unplugging it makes it not fire at all
3- if you can look at a engine running, and be able to tell what cylinder is not firing i suggest you take a job with the pyschic hotline
2- a bad coil pack creates a mis-fire, unplugging it makes it not fire at all
3- if you can look at a engine running, and be able to tell what cylinder is not firing i suggest you take a job with the pyschic hotline
09-01-2005, 07:38 AM
#11
Junior Member
Join Date: Jul 2005
Posts: 28
If you can borrow an infrared temperature indicator ,you can check for misfire conditions by checking the temperature at the base of the spark plug with the engine running (works better from a cold start) the misfiring plug will usually be much cooler. These tools have gotten a lot cheaper I've seen some for about $70 but I don't know how good the cheap ones are. The link below shows an example of one.
http://www.raytek-northamerica.com/c...cat_id=2.3.3.3
http://www.raytek-northamerica.com/c...cat_id=2.3.3.3
09-01-2005, 01:04 PM
#12
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Thread Starter
Join Date: Jul 2005
Posts: 32
Originally Posted by Stuntin' 101
1- that method will not always work..
2- a bad coil pack creates a mis-fire, unplugging it makes it not fire at all
3- if you can look at a engine running, and be able to tell what cylinder is not firing i suggest you take a job with the pyschic hotline
2- a bad coil pack creates a mis-fire, unplugging it makes it not fire at all
3- if you can look at a engine running, and be able to tell what cylinder is not firing i suggest you take a job with the pyschic hotline
1. You may be correct about this one. I'm sure in some circumstances it won't work.
2. Exactly. That's what helps point you in the right direction.
3. I agree. Leave that to Miss Cleo.
Unplugging the coils one by one will not hurt a thing. If anything it may throw a code. You must make sure that your engine is missfiring before you start unplugging the coils. Otherewise this will not work.
Unplug one coil. If the engine missies consistantly and than all of a sudden hicups that coil is fine. Plug that one back up and unplug another. If the engine missies consistantly and than all of a sudden hicups again that coil is fine. Plug that one up and unplug another. If the engine misses consitstantly and never hicups than that coil you have unplugged is the malfunctioning coil.
You see? If you unplug a good coil then the engine will naturally miss on that cylinder. That'S automatic. If it misses again then that means that your malfuctioning coil is still plugged up.
Like I said. The car must be missing first.
WES
10-24-2005, 04:37 PM
#13
Luvs his Max
Join Date: Oct 2002
Posts: 117
Originally Posted by condor
I understand the logic but can I just remove the cover and start unplugging coils by hand with the engine running? Are there any safety concerns doing this?
Thanks
10-24-2005, 07:05 PM
#17
Member
Join Date: Sep 2005
Posts: 60
yuppp those simple solutions are the best
one cylinder, the #2, of mine was misfiring and threw a code
i got all psyched and whipped out the ol multimeter to see if that was the issue
poppa dukes says "shut your trap and look here, youngster", and procedes to switch the coil packs between the #2 and #4 cylinders, then he says "drive it and see if the code changes", sure nuff it did - much respect to old(56) people
one cylinder, the #2, of mine was misfiring and threw a code
i got all psyched and whipped out the ol multimeter to see if that was the issue
poppa dukes says "shut your trap and look here, youngster", and procedes to switch the coil packs between the #2 and #4 cylinders, then he says "drive it and see if the code changes", sure nuff it did - much respect to old(56) people
10-26-2005, 12:56 PM
#18
Hello all -- I have just registered, but am not allowed to post a new thread yet. There are several posts about the infamous coil packs on the 4th generation cars. I have a 1998 SE automatic, with approx 126K (purchased from a one owner with 106K) and I believe the original packs. Since I've owned the car the past three years, I have done the proper maintenance and haven't had too many headaches. My question involves the coil packs and whether they gradually deteriorate to the point of failure or if they are like a light bulb -- no warning, works today, not tomorrow. I only ask because I am currently trying to tune my car and make it as smooth as it came from the factory. There have been times recently when I started my car, drove it many miles and it ran great and then restarted it a 1/2 hour later or the next day and it didn't feel right at idle or when accelerating. Giving it some gas made it feel a little rough, but not to the point of "stumbling." I replaced the KS (without removing the intake) and recently the fuel filter. Cleaned the TB and EGR ports. Haven't pulled the IACV or PCV valve, but plan on doing those as well. I have tried two fuel injector cleaners (Lucas and Chevron) at various times and it ran a little better for a while, but still has the intermitent rough idle and acceleration between 1500-3000 rpm that mysteriously goes away.
Is there anyone out there who has experienced this problem? Because there are no misfire codes and the CEL has never come on I am hesistant to start pulling the coil packs and testing/replacing them. I was also planning on having a complete fuel injection cleaning performed, but because the car will run as smooth as glass for many miles at a time, I question whether the injectors have anything blocking their flow.
If anyone has any knowledge about the failure of a coil pack (sudden vs gradual) I would be greatly appreciated before I start spending money on unnecessary repairs. Also, any other information regarding my reply is welcome. Thanks. Ted, Chicago
10-26-2005, 04:00 PM
#20
what sky jumper said is kinda true. Driving around with a misfiring cylinder will eventually (could be 1000s of miles could be less) destroy your cat (because of unburned fuel), but just unplugging a coil for a few seconds won't do any harm.
12-12-2006, 03:14 PM
#21
Junior Member
Join Date: Dec 2006
Posts: 27
Big costly problem with coils
It just started with my car yesterday and now I have a big costly problem. Yesterday my car (95 SE 157k) started bogginging and idling rough.. This morning I went to work and it was not as noticable. But when I got in to go to lunch it was just loud as hell.. I had to turn it off for a while and think of what to do.. I'm not a mechanic so this was urking me. I drove it (very slowly) two blocks to a mechanic who took off the cover and removed one of the coils, underneath, (the rubber was shredded) he also told me that the plug thread was stripped so he might have to open up the motor and maybe order a new head..Can it be that bad..???? I He also told me that a new coil would be about 180 bucks!!Is that really the cost?...please help!!!
Any advice would be greatly appreciated..
Any advice would be greatly appreciated..
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