Repeated multiple ignition coil failure. K12 Micra
Discussion
2008 Micra 1.2
Recent full service including spark plugs (unsure if relevant). Runs fine for a few days.
Car has small bump, front end. Radiator damaged. Driven a few miles home.
Parked up for a week. Bonnet, slam panel and radiator replaced with parts from breaker.
I drove the car for a few miles, all running well. Car returned to young owner. Driven around that night and next morning, all okay. Lunchtime it starts running very rough and won't drive.
Recovered by AA. Mention of possibly exhaust valves.
I have a look at car. Scan says multiple cylinder misfire.
Start car, runs really rough for maybe 20/30 seconds and cuts out. Unplugging coils 1, 2 and 3 (looking at engine left to right) makes no difference, so only running on number 4. Coil number 4 then used in cylinders 1,2 & 3, and run the engine, so 3 failed coils.
Coils sourced from breaker, installed, car runs perfect. I drive it a mile or 2, all seems good. Returned to owner. It does a couple of 30 mile trips the next day. No issues. Next again day, starts running rough. Coils 1 & 2 failed.
Replaced again with used coils but this time spark plugs also changed. Car starts and idles fine. Left running for a bit, then go to move it and coils fail again.
Any suggestions of what I should be looking at? Engine loom? ECU?
Recent full service including spark plugs (unsure if relevant). Runs fine for a few days.
Car has small bump, front end. Radiator damaged. Driven a few miles home.
Parked up for a week. Bonnet, slam panel and radiator replaced with parts from breaker.
I drove the car for a few miles, all running well. Car returned to young owner. Driven around that night and next morning, all okay. Lunchtime it starts running very rough and won't drive.
Recovered by AA. Mention of possibly exhaust valves.
I have a look at car. Scan says multiple cylinder misfire.
Start car, runs really rough for maybe 20/30 seconds and cuts out. Unplugging coils 1, 2 and 3 (looking at engine left to right) makes no difference, so only running on number 4. Coil number 4 then used in cylinders 1,2 & 3, and run the engine, so 3 failed coils.
Coils sourced from breaker, installed, car runs perfect. I drive it a mile or 2, all seems good. Returned to owner. It does a couple of 30 mile trips the next day. No issues. Next again day, starts running rough. Coils 1 & 2 failed.
Replaced again with used coils but this time spark plugs also changed. Car starts and idles fine. Left running for a bit, then go to move it and coils fail again.
Any suggestions of what I should be looking at? Engine loom? ECU?
Are the coils getting hot to the touch before they blow? The only reason I can think of for the coils failing is overheating due to excessive voltage or excessive dwell. Excessive voltage seems unlikely and would likely cause all sorts of other problems, but it's easy enough to check for with a volt meter.
ETA are the coils physically mounted correctly the same as originally?
ETA are the coils physically mounted correctly the same as originally?
Edited by GreenV8S on Tuesday 4th April 22:11
Are you sure the coils are faulty? A misfire code doesn't necessarily mean a plug is not firing, it just means the crankshaft speed is irregular which suggests a misfire.
Thinking outside of the box, was the exhaust cat damaged in this bump? If I remember correctly the cat is at the front of the engine below the manifold on these, if it is damaged, ceramic dust etc will be easily be ingested into the engine at low speed due to valve timing overlap and that can cause all sorts of damage including random sticking valves.
Thinking outside of the box, was the exhaust cat damaged in this bump? If I remember correctly the cat is at the front of the engine below the manifold on these, if it is damaged, ceramic dust etc will be easily be ingested into the engine at low speed due to valve timing overlap and that can cause all sorts of damage including random sticking valves.
oakdale said:
Are you sure the coils are faulty? A misfire code doesn't necessarily mean a plug is not firing, it just means the crankshaft speed is irregular which suggests a misfire.
I think my initial test pointed to the coils. The coil from number 4 ran all 4 cylinders. I only then tried one of the other coils in cylinder 4 and that didn't work. Simply removing the coils and re-fitting the same ones makes no difference, yet fires straight up when the replacements are fitted. This suggests to me that it is indeed the coils that are faulty. But I don't really know enough to be 100% sure.oakdale said:
Thinking outside of the box, was the exhaust cat damaged in this bump? If I remember correctly the cat is at the front of the engine below the manifold on these, if it is damaged, ceramic dust etc will be easily be ingested into the engine at low speed due to valve timing overlap and that can cause all sorts of damage including random sticking valves.
Certainly a possibility.E-bmw said:
I would be trying to source new coils to rule out a potential "common" failure.
It has crossed my mind, but it would be an expensive test for the owner - New coils are £40 each.It would also seem really unlucky that that 8 coils have failed in short order (and never cylinder 4)
Had an A6 that did this. Curiously it was also right after changing the plugs. Several COPs over a couple of weeks including repeat failures.
The solution in my case was obvious. I changed the plugs again for some different ones and it lasted for another 50k miles. If I recall correctly I had used some “fancy” ones and replaced them with less fancy ones. Sketchy on details, was a decade ago.
The solution in my case was obvious. I changed the plugs again for some different ones and it lasted for another 50k miles. If I recall correctly I had used some “fancy” ones and replaced them with less fancy ones. Sketchy on details, was a decade ago.
If the ECU switches each coil individually and the cables from ECU to coils 1, 2 and 3 shorted to earth there is a possibility that those 3 coils would burn out if the vehicles ignition wasn't switched off as soon as the shorts occurred
and
If cables to coils 1 and 2 shorted to earth during the next run they could possibly burn out if the vehicles ignition wasn't switched off as soon as the shorts occurred
and
If cables to coils 1 and 2 shorted to earth during the next run they could possibly burn out if the vehicles ignition wasn't switched off as soon as the shorts occurred
Just to update this thread -
After a few months off the road, 4 brand new coils were fitted and all has been fine for the past few weeks. I was certain that something else was causing the failures.
After a few months off the road, 4 brand new coils were fitted and all has been fine for the past few weeks. I was certain that something else was causing the failures.
E-bmw said:
I would be trying to source new coils to rule out a potential "common" failure.
Appears this was the correct advice.I own a Micra 160SR 55 plate and over the years have had many misfires with engine check light on, replaced numerous coils many times, I also work at Nissan and built the very car I have which I bought 2nd hand with 50,000k. It now has 148,000k and started to misfire again however this time I changed a coil it was ok but then the misfire returned after 1 week so I decided to take some advice from an engineer at work, turns out it's the crap E10 fuel that carbs up the fuel system over the years so I >
On an empty tank poured a full bottle of CleanDrive into the tank, put £20 (quarter tank) of super unleaded E5 in after 30miles driving steady BOOM misfire disappeared check light went off car running like new, 800miles later same again check light running rough, another bottle of Cleandrive & boom perfect again,
My injectors were blocked because of the crap E10 fuel and probably the whole fuel system.
I have now put a tin of BG 44K platinum in with a half tank of fuel (E5 fuel), this is apparently the No1 best fuel system cleaner. I now have a car running exceptionally well with increased mpg & superb response. I will add 44k again in 1500 miles to make sure it is getting rid of all the carbon build up & going forward use only E5 fuel.
I wish I had known this before & not wasted money on coil after coil & spark plugs when it's the crap E10 fuel all along.
The government are responsible for breaking everyone's cars with this 10% ethenol E10 and in the coming years current cars will have the same issues.
Ethanol blended gasoline can cause serious engine damage when used regularly. It is corrosive and highly water soluble, often leading to storage problems. If left, water in the fuel system can cause rusting, fuel degradation and other problems.
On an empty tank poured a full bottle of CleanDrive into the tank, put £20 (quarter tank) of super unleaded E5 in after 30miles driving steady BOOM misfire disappeared check light went off car running like new, 800miles later same again check light running rough, another bottle of Cleandrive & boom perfect again,
My injectors were blocked because of the crap E10 fuel and probably the whole fuel system.
I have now put a tin of BG 44K platinum in with a half tank of fuel (E5 fuel), this is apparently the No1 best fuel system cleaner. I now have a car running exceptionally well with increased mpg & superb response. I will add 44k again in 1500 miles to make sure it is getting rid of all the carbon build up & going forward use only E5 fuel.
I wish I had known this before & not wasted money on coil after coil & spark plugs when it's the crap E10 fuel all along.
The government are responsible for breaking everyone's cars with this 10% ethenol E10 and in the coming years current cars will have the same issues.
Ethanol blended gasoline can cause serious engine damage when used regularly. It is corrosive and highly water soluble, often leading to storage problems. If left, water in the fuel system can cause rusting, fuel degradation and other problems.
Edited by DirkDaring on Saturday 20th January 14:19
Edited by DirkDaring on Saturday 20th January 14:21
DirkDaring said:
I own a Micra 160SR 55 plate and over the years have had many misfires with engine check light on, replaced numerous coils many times, It now has 148,000k and started to misfire again however this time I changed a coil it was ok but then the misfire returned after 1 week so I decided to take some advice from an engineer at work, turns out it's the crap E10 fuel that carbs up the fuel system over the years
If the cause was fuel how did changing the coil fix it even temporarily? Neither system is connected in any way.DirkDaring said:
I wish I had known this before & not wasted money on coil after coil & spark plugs when it's the crap E10 fuel all along.
The government are responsible for breaking everyone's cars with this 10% ethenol E10 and in the coming years current cars will have the same issues.
In the coming years current cars won't have the issue as they are designed to run on it & have been designed to do so for many years now.The government are responsible for breaking everyone's cars with this 10% ethenol E10 and in the coming years current cars will have the same issues.
DirkDaring said:
Ethanol blended gasoline can cause serious engine damage when used regularly. It is corrosive and highly water soluble, often leading to storage problems. If left, water in the fuel system can cause rusting, fuel degradation and other problems.
E10 fuel only causes damage to cars that were not designed to run on it. Or if it is stored poorly and water manages to get in to the tanks. Because Ethanol is hygroscopic not water soluble.Best get your engineer to check his facts first next time.
ETA. Username checks out.
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