Defective Coil Pack Symptoms
03-06-2008, 05:45 AM
#1
Defective Coil Pack Symptoms
After getting my defective coil pack replaced, I thought I’d give you a list of symptoms to identify this problem. I looked in the forums quite a bit and was able to piece the information together but I thought I’d share a detailled list of symptoms so others can identify the problem more quickly. Maybe this has been done before, but just in case here it comes:
• The car starts running very rough, especially at low revolution (between 1-4K RPM) and you can feel it shake in the stick and pedals. Seems less apparent >4K RPM.
• I noticed a different sound (louder than usual)
• Smoke from the exhaust not coming out as a steady stream but in chunks (“puff puff puff”) instead of the usual steady (“rrrrrrrrrr”)
• Very noticeable lack of power
• Sometimes, the RPM drops while accelerating (RPM would drop from 3.5K to 2K for no reason at open throttle)
• Sometimes, the SES light comes on and/or blinks while accelerating
• The SES code was [P0302] CYL 2 MISFIRE
I know there are other problems that can cause these symptoms but if you’re experiencing something similar, you should get your coil packs checked (or check them yourself).
Please feel free to add to this with any relevant information!!
• The car starts running very rough, especially at low revolution (between 1-4K RPM) and you can feel it shake in the stick and pedals. Seems less apparent >4K RPM.
• I noticed a different sound (louder than usual)
• Smoke from the exhaust not coming out as a steady stream but in chunks (“puff puff puff”) instead of the usual steady (“rrrrrrrrrr”)
• Very noticeable lack of power
• Sometimes, the RPM drops while accelerating (RPM would drop from 3.5K to 2K for no reason at open throttle)
• Sometimes, the SES light comes on and/or blinks while accelerating
• The SES code was [P0302] CYL 2 MISFIRE
I know there are other problems that can cause these symptoms but if you’re experiencing something similar, you should get your coil packs checked (or check them yourself).
Please feel free to add to this with any relevant information!!
Last edited by Marl1979; 03-06-2008 at 09:47 AM.
03-06-2008, 09:55 AM
#4
How-to test Coil Packs
I thought I'd add the information on how to test the coil packs yourself to make it a more complete thread...
Mods remove if you will, i figure it might be handy 
How to verify if your coil packs work!
Engine worked with: 1996 maxima
Requires: An ohmmeter (cheap purchase at radio shack....)
Conditions: Make sure your engine is cold, or it'll be hot on your hands
you have 6 Ignition coil packs. 3 up front and 3 near your firewall. (when asking for new ones, they are referred to as L and R)
3 are hidden behind the plastic piece on your engine that says NISSAN... simply remove the bolts and remove the plastic piece.
once removed, you should see 3 coil packs. un plug and test them one at a time.
I won't go into how to remove them since it should be fairly obvious
Simply remove both bolts (do one coil pack at a time...) and pull the coil pack out. i had one where it was very hard to get out... so you may have to pull hard...
Once out, look at the area where you removed the electrical plug. You should see a "+" on the back end of the electrical plug. There should also be the letter "B"....
the spot where you see the positive symbol, means that's prong number one on the electrical connector.
To test:
Turn on your ohmmeter and place the positive wire on the 1st prong in the electrical plug of the coil pack. The negative wire should be touching the middle prong. Verification of the ohmmeter at this time should say "0" aka infinite... if it's anything else, the pack should be changed. Next test: reverse the wires... positive on the middle prong and negative on the 1st prong.... on a new coil pack, it should give a value of approximately 1.3-1.7 mega ohms. If any of the readings are off, replace the coil pack.
Note: Firewall coil packs are extremely easy to find, simply look in the cracks of the intake header. you'll see 3 similar looking coil packs to the front ones. The exception with these is that they are longer and look a slight bit different. removal is the same process as the front coil packs. Simply pay special attention to not dropping the screws in the intake area... it'll be hard to get out
to test: follow the front coil pack testing method. Look for the Positive symbol, this is your first prong... and go from there.
Good luck...
How to verify if your coil packs work!
Engine worked with: 1996 maxima
Requires: An ohmmeter (cheap purchase at radio shack....)
Conditions: Make sure your engine is cold, or it'll be hot on your hands
you have 6 Ignition coil packs. 3 up front and 3 near your firewall. (when asking for new ones, they are referred to as L and R)
3 are hidden behind the plastic piece on your engine that says NISSAN... simply remove the bolts and remove the plastic piece.
once removed, you should see 3 coil packs. un plug and test them one at a time.
I won't go into how to remove them since it should be fairly obvious
Simply remove both bolts (do one coil pack at a time...) and pull the coil pack out. i had one where it was very hard to get out... so you may have to pull hard...Once out, look at the area where you removed the electrical plug. You should see a "+" on the back end of the electrical plug. There should also be the letter "B"....
the spot where you see the positive symbol, means that's prong number one on the electrical connector.
To test:
Turn on your ohmmeter and place the positive wire on the 1st prong in the electrical plug of the coil pack. The negative wire should be touching the middle prong. Verification of the ohmmeter at this time should say "0" aka infinite... if it's anything else, the pack should be changed. Next test: reverse the wires... positive on the middle prong and negative on the 1st prong.... on a new coil pack, it should give a value of approximately 1.3-1.7 mega ohms. If any of the readings are off, replace the coil pack.
Note: Firewall coil packs are extremely easy to find, simply look in the cracks of the intake header. you'll see 3 similar looking coil packs to the front ones. The exception with these is that they are longer and look a slight bit different. removal is the same process as the front coil packs. Simply pay special attention to not dropping the screws in the intake area... it'll be hard to get out
to test: follow the front coil pack testing method. Look for the Positive symbol, this is your first prong... and go from there.
Good luck...
10-13-2008, 09:54 AM
#6
Hmmm. Usually when testing resistance with a multimeter it shows 0 when there is continuity in a closed circuit with no resistance. Infinite resistance is indicated by something else, like a dash or some other non-numerical display.
Another problem with testing resistance to determine failure of a coil is that ignition coil failure is almost always an insulation breakdown when the coil is hot, so you should test with a coil that is up to temperature. Even then it may not indicate anything is wrong, since insulation usually fails when there is (significant) voltage present, and a multimeter is not going to give enough voltage to cause an insulation failure. So you may end up with a false negative (i.e. no indication of anything wrong) with this method.
A high-pot test would be conclusive, but that takes special equipment that the home mechanic doesn't usually have.
Another problem with testing resistance to determine failure of a coil is that ignition coil failure is almost always an insulation breakdown when the coil is hot, so you should test with a coil that is up to temperature. Even then it may not indicate anything is wrong, since insulation usually fails when there is (significant) voltage present, and a multimeter is not going to give enough voltage to cause an insulation failure. So you may end up with a false negative (i.e. no indication of anything wrong) with this method.
A high-pot test would be conclusive, but that takes special equipment that the home mechanic doesn't usually have.
10-13-2008, 12:25 PM
#8
Member
Join Date: Nov 2006
Posts: 251
Also, when you buy a brand new coil, CHECK it again and compare to any healthy coil that is already on your car- they should read same readings. Beleive it or not, I bought a defective coil at O'Reiley a year ago and decided to test it just for fun, and it showed OPEN circuit, meaning, when the ohmmeter leads were reversed, it showed "infinite", test every electronic component that you buy from autoparts, they are selling defective stuff sometimes.
10-29-2008, 12:07 PM
#11
I'll repeat what I said earlier, since maybe it wasn't clear. If you use a multimeter, the resistance of a coil pack may look normal even for a faulty coil pack. So if the resistance you get is way out of spec, then the coil is definitely bad. But if it isn't out of spec, it may still be bad.
12-28-2009, 04:15 PM
#14
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Join Date: Dec 2009
Posts: 1
I have a 1996 hyundai accent with the same symptoms. Missfiring and sometimes backfiring. The Check engine light flashed a few times and i had no idea what the problem was. At first i changed the oil and the oil filter because i thought the oil had water in it which was causing it to run rough. Then, i took it to a garage and they changed my plugs, wires, air filter and gas filter for 400.00. I thought my problems were over but about 5 kilometers away from the garage my car started lacking power, missing, and stalling. I went out and bought a new coil pack which costed me a little over 100.00 and put it on. Now my car works better than ever before.
12-28-2009, 04:30 PM
#15
I have a 1996 hyundai accent with the same symptoms. Missfiring and sometimes backfiring. The Check engine light flashed a few times and i had no idea what the problem was. At first i changed the oil and the oil filter because i thought the oil had water in it which was causing it to run rough. Then, i took it to a garage and they changed my plugs, wires, air filter and gas filter for 400.00. I thought my problems were over but about 5 kilometers away from the garage my car started lacking power, missing, and stalling. I went out and bought a new coil pack which costed me a little over 100.00 and put it on. Now my car works better than ever before.
12-28-2009, 05:07 PM
#16
I have a 1996 hyundai accent with the same symptoms. Missfiring and sometimes backfiring. The Check engine light flashed a few times and i had no idea what the problem was. At first i changed the oil and the oil filter because i thought the oil had water in it which was causing it to run rough. Then, i took it to a garage and they changed my plugs, wires, air filter and gas filter for 400.00. I thought my problems were over but about 5 kilometers away from the garage my car started lacking power, missing, and stalling. I went out and bought a new coil pack which costed me a little over 100.00 and put it on. Now my car works better than ever before.
why are u here?
12-28-2009, 07:12 PM
#17
I have a 1996 hyundai accent with the same symptoms. Missfiring and sometimes backfiring. The Check engine light flashed a few times and i had no idea what the problem was. At first i changed the oil and the oil filter because i thought the oil had water in it which was causing it to run rough. Then, i took it to a garage and they changed my plugs, wires, air filter and gas filter for 400.00. I thought my problems were over but about 5 kilometers away from the garage my car started lacking power, missing, and stalling. I went out and bought a new coil pack which costed me a little over 100.00 and put it on. Now my car works better than ever before.
01-07-2010, 06:18 PM
#18
Join Date: Nov 2009
Posts: 16
01-10-2010, 01:10 PM
#19
Newbie - Just Registered
Join Date: Jan 2010
Location: New Zealand
Posts: 5
Hi,
I tested my coil packs and get the 1.7Mohm reading between the IB and G pins but I don't get the continuity reading between the positive and G.
I'm trying to sort out an inconsistent idle on a 95 2.5 Cefiro/Maxima with 167k.
Apart from the idle the car runs beautifully and economically.
I tested my coil packs and get the 1.7Mohm reading between the IB and G pins but I don't get the continuity reading between the positive and G.
I'm trying to sort out an inconsistent idle on a 95 2.5 Cefiro/Maxima with 167k.
Apart from the idle the car runs beautifully and economically.
01-10-2010, 09:45 PM
#20
Anyone else had backfire from the intake caused by bad coil packs?
I was having loud intake backfires at odd times followed by a quick loss of power.. sometimes multiple backfires in spurts. Replacing my coils solved the issue. Just something to keep in mind
I was having loud intake backfires at odd times followed by a quick loss of power.. sometimes multiple backfires in spurts. Replacing my coils solved the issue. Just something to keep in mind
01-24-2010, 10:11 PM
#21
Member
Join Date: Aug 2009
Location: Portland, OR
Posts: 38
Same problem, coils check out OK?
I have the same exact symptoms as the first post, except intermittently. So I checked the coils, but each one tested fine. Now I'm not sure what to look for. My throttle body is clean and the plugs are new. What else should I suspect now?
01-25-2010, 07:53 AM
#22
Time to repeat what I said earlier, I guess.
Ignition coils operate under high voltage. When they become defective, it is because of a breakdown in internal insulation at high voltage. The insulation may be perfectly fine at low voltage. Since your multimeter applies at most about 9V, you are only testing the low voltage resistance, which may appear perfectly normal, even though the insulation is breaking down during actual operation. Heat also lowers the standoff voltage potential of insulation, which is why an ignition coil may operate fine when the engine is cold, and then start missing when it heats up.
Ignition coils operate under high voltage. When they become defective, it is because of a breakdown in internal insulation at high voltage. The insulation may be perfectly fine at low voltage. Since your multimeter applies at most about 9V, you are only testing the low voltage resistance, which may appear perfectly normal, even though the insulation is breaking down during actual operation. Heat also lowers the standoff voltage potential of insulation, which is why an ignition coil may operate fine when the engine is cold, and then start missing when it heats up.
Last edited by Stephen Max; 01-25-2010 at 08:00 AM.
01-25-2010, 10:46 AM
#23
Member
Join Date: Aug 2009
Location: Portland, OR
Posts: 38
Time to repeat what I said earlier, I guess.
Ignition coils operate under high voltage. When they become defective, it is because of a breakdown in internal insulation at high voltage. The insulation may be perfectly fine at low voltage. Since your multimeter applies at most about 9V, you are only testing the low voltage resistance, which may appear perfectly normal, even though the insulation is breaking down during actual operation. Heat also lowers the standoff voltage potential of insulation, which is why an ignition coil may operate fine when the engine is cold, and then start missing when it heats up.
Ignition coils operate under high voltage. When they become defective, it is because of a breakdown in internal insulation at high voltage. The insulation may be perfectly fine at low voltage. Since your multimeter applies at most about 9V, you are only testing the low voltage resistance, which may appear perfectly normal, even though the insulation is breaking down during actual operation. Heat also lowers the standoff voltage potential of insulation, which is why an ignition coil may operate fine when the engine is cold, and then start missing when it heats up.
It would be a waste to spend $300 on new coils only to find something else is the problem.
01-25-2010, 12:43 PM
#24
I tested them when they were at normal operating temperature, and they tested fine. From your post, I can gather that either 1) The coils are fine, and something else is the problem, or 2) the coils are not fine, and they are causing the problem. What is the normal procedure when the car gives off classic coil symptoms, but they are apparently OK?
It would be a waste to spend $300 on new coils only to find something else is the problem.
It would be a waste to spend $300 on new coils only to find something else is the problem.
If you can determine which cylinder is misfiring (assuming it's only one or two that are giving you problems), then you can swap coils with a different cylinder (that you know is not misfiring) and see if the misfiring moves to the cylinder you put the suspect coil in. If the same cylinder still misfires, then it is not a defective coil problem. If the cylinder you put the suspect coil in misfires, then you have found the source of the problem and you can just replace the one coil.
The traditional way to determine which cylinder is misfiring is by disconnecting coils one by one and seeing how it affects idle speed. If there is no change in idle speed after you disconnect its coil, then that is the cylinder that is misfiring.
01-26-2010, 01:43 AM
#25
Member
Join Date: Aug 2009
Location: Portland, OR
Posts: 38
If you can determine which cylinder is misfiring (assuming it's only one or two that are giving you problems), then you can swap coils with a different cylinder (that you know is not misfiring) and see if the misfiring moves to the cylinder you put the suspect coil in. If the same cylinder still misfires, then it is not a defective coil problem. If the cylinder you put the suspect coil in misfires, then you have found the source of the problem and you can just replace the one coil.
The traditional way to determine which cylinder is misfiring is by disconnecting coils one by one and seeing how it affects idle speed. If there is no change in idle speed after you disconnect its coil, then that is the cylinder that is misfiring.
The traditional way to determine which cylinder is misfiring is by disconnecting coils one by one and seeing how it affects idle speed. If there is no change in idle speed after you disconnect its coil, then that is the cylinder that is misfiring.
My symptoms are:
-Occasional misfire feel and sound
-Blinking CEL upon acceleration
-Steady CEL with 0505 error (no error)
-Occasional lack of power
-Occasional bad starts (this may be unrelated, however)
I'm stumped. Any other suggestions?
01-26-2010, 08:03 AM
#26
Unfortunately, I did both the "disconnection" test and the multimeter test. Both suggest that my coils are fine. I cannot place the misfire, but know it exists occasionally. The problem is that it comes and goes.
My symptoms are:
-Occasional misfire feel and sound
-Blinking CEL upon acceleration
-Steady CEL with 0505 error (no error)
-Occasional lack of power
-Occasional bad starts (this may be unrelated, however)
I'm stumped. Any other suggestions?
My symptoms are:
-Occasional misfire feel and sound
-Blinking CEL upon acceleration
-Steady CEL with 0505 error (no error)
-Occasional lack of power
-Occasional bad starts (this may be unrelated, however)
I'm stumped. Any other suggestions?
Your symptoms point to intermittent coil failure. Your car is a 99, which means it has the ignition coils known to have a high failure rate (I believe the problem years were 99-01). You can wait until the bad one(s) go completely bad, which will simplify diagnosis, or you can just go ahead and buy a set now and see if that cures the problem. A gamble, I know, but at this point you are reduced to a replace-and-see-if-that-fixes-the-problem strategy, and there are good reasons to suspect coil failure and not a different problem.
01-26-2010, 10:55 AM
#27
Member
Join Date: Aug 2009
Location: Portland, OR
Posts: 38
Your symptoms point to intermittent coil failure. Your car is a 99, which means it has the ignition coils known to have a high failure rate (I believe the problem years were 99-01). You can wait until the bad one(s) go completely bad, which will simplify diagnosis, or you can just go ahead and buy a set now and see if that cures the problem. A gamble, I know, but at this point you are reduced to a replace-and-see-if-that-fixes-the-problem strategy, and there are good reasons to suspect coil failure and not a different problem.
01-26-2010, 07:48 PM
#28
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Join Date: Jan 2010
Posts: 10
my 1999 i30 has pretty much all those symptoms listed above except a few but im not sure how much longer should i drive with these bad coils.
are they really that serious since i've already driven it for almost 4k miles and it might take a while longer for me to get that much money to replace the coils... i know i will have to replace them eventually but will these bad coils damage my engine or something horribly adverse?
are they really that serious since i've already driven it for almost 4k miles and it might take a while longer for me to get that much money to replace the coils... i know i will have to replace them eventually but will these bad coils damage my engine or something horribly adverse?
Last edited by brunos; 01-26-2010 at 07:50 PM.
01-27-2010, 10:15 AM
#29
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Join Date: May 2006
Posts: 6
I have the exact same symptoms as listed above. BUT...I checked my coils today while the car was running and as I unplugged each coil, the idle changed. This means they are good right? The car was at normal operating temp. I am getting no CELs
02-01-2010, 11:17 PM
#31
Member
Join Date: Aug 2009
Location: Portland, OR
Posts: 38
From what I understand, that is not a conclusive test. In medical terms, you may be getting a "false positive".
02-12-2010, 09:17 AM
#32
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Join Date: Jan 2010
Location: Fort Walton, KS
Posts: 1
I am having these same issues:
-Occasional misfire feel and sound (intermittent pulsing while sitting at traffic light and low rpms)
-Occasional lack of power (Hit the gas, car accelerates slowly and then finally kicks in like a Max should)
I have been testing many other things, all seem to be ok. I am not throwing any misfire codes, but that's not to say there isn't an issue. I tested my coils cold a couple weeks ago(which I need to retest while warm) and the resistance I got between the 6 coils was all over the place. My question is should the resistance be somewhat close between all of the coils? I had some very low and very high readings between the coils. Nothing was within a few digits of the others. Thanks.
-Occasional misfire feel and sound (intermittent pulsing while sitting at traffic light and low rpms)
-Occasional lack of power (Hit the gas, car accelerates slowly and then finally kicks in like a Max should)
I have been testing many other things, all seem to be ok. I am not throwing any misfire codes, but that's not to say there isn't an issue. I tested my coils cold a couple weeks ago(which I need to retest while warm) and the resistance I got between the 6 coils was all over the place. My question is should the resistance be somewhat close between all of the coils? I had some very low and very high readings between the coils. Nothing was within a few digits of the others. Thanks.
08-12-2010, 11:52 PM
#34
i have a similar issue except for the fact that i cant even get mien started i have ohmed out my injectors AND my coils and everything is within nissan acceptable specs im going tomorrow to get another set of battery terminals and a 4gauge wire to do another ground .. maybe that will help it out.. it couldnt hurt lol
04-08-2011, 10:56 AM
#36
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Location: Worcester, MA
Posts: 4,011
05-23-2011, 10:58 AM
#38
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Location: Worcester, MA
Posts: 4,011
