coil packs - how variable can they be?

[stevetwors]

My back left coil pack went bad because of water. I bought a used one and replaced it. The motor no longer is missing, its firing on all cylinders now, but the car is just not the same. It is still running noticeably rough, just not nearly as bad as when the previous coil pack was completely dead. My theory is the used coil pack i bought is just weak or on its way out.

1. Do coil packs weaken over time? They provide a weaker spark and this causes that cylinder to fire slightly later in the combustion stroke?

2. How bad is it to drive around with no spark on one of the cylinders? I was forced to drive around at least 200 miles like this, and drove it semi-hard a couple times, this was before I knew it was missing because i had the stereo loud.

My fear is the coil pack replacement is fine, but damage has been done to that non firing cylinder. I'm worried the gas thinned the oil out and also caused oil to wash away in that cylinder.

I won't know until the car gets out of the body shop and I can do a comp test.

 

[UnhuZ]

check the compression on that cylinder.

my bad coil cost me $3000 in parts and labour to fix....i had all 4 valves burnt on that cylinder due to misfires

see this threads where the problem is discussed:

HELP!! car hesitates after driving in heavy rain storm!

Honda made a mistake or is it suppose to be that way RWG

NSX Injector O RINGS If you care

 

[4AU4LIFE]

I can't remeber if the coils are different front to back or not. I'm sure someone else can chime in to confirm that.
Did it say anything of the black casing of the coil pack about front or back specifically?
The way I have understood electrical items is that they usually don't give a warning or anything but rather just go bad...and usually at the worst time possible.
Sorry to hear of your continued troubles.
BTW, didn't you just buy this car recently?

 

[stevetwors]

yea i just bought this car. guys no offense, its a great car in so many ways, but this is fuking ridiculous. a car should not be so sensitive that you wash the car when you first get it, causes it to misfire because of the water, and when the coil is replaced its already too late the valves are burnt up. this is most likely what has happened. i can hear air hissing, sounds like combustion leaking out the intake valves and resonating out the aftermarket air filter.

grrrreat.

 

[stevetwors]

I can't remeber if the coils are different front to back or not. I'm sure someone else can chime in to confirm that.
Did it say anything of the black casing of the coil pack about front or back specifically?
The way I have understood electrical items is that they usually don't give a warning or anything but rather just go bad...and usually at the worst time possible.
Sorry to hear of your continued troubles.
BTW, didn't you just buy this car recently?

the rear and front banks are different. i got the correct rear bank version.

 

[UnhuZ]

Fronts have "FR" in white
Rears have "RR" in white also

 

[ScienceofSpeed]

yea i just bought this car. guys no offense, its a great car in so many ways, but this is fuking ridiculous. a car should not be so sensitive that you wash the car when you first get it, causes it to misfire because of the water, and when the coil is replaced its already too late the valves are burnt up. this is most likely what has happened. i can hear air hissing, sounds like combustion leaking out the intake valves and resonating out the aftermarket air filter.

grrrreat.

The coils usually work or don't work.

Washing the car will not damage the coils if the seals are installed properly. If they are not there, you can't really blame the car.

The hissing you are hearing is normal from the aftermarket filter (and likely an induction scoop).

If you're worried about power, a compression test will give you quick insight into the condition of the engine.

Cheers,
-- Chris

 

[UnhuZ]

The coils usually work or don't work.

Washing the car will not damage the coils if the seals are installed properly. If they are not there, you can't really blame the car.

Chris...its not that liquid....

my car had everything in place...the only non OEM and in good shape was the rust and corrosion on my coilpacks...every seal was there....

till today, nobody knows how it happened...the only evidence of something wrong, was really the coil

there is no seal to prevent water from getting arround the coils....is simple to prove me wrong...get a nsx, see if it have all the gaskets and seals in place...then close the hatch and wash it normally...you WILL see water over the coilcover....when removed, you WILL see water under it....

this is a flaw....and it have consequences....expensive ones...we have just to live with it

 

[goldNSX]

there is no seal to prevent water from getting arround the coils

Actually there is a seal (foam) around the cover but it doesn't keep the water out of the coil area. Also the rubber on the coil gets wider over time and makes them more sensitive to water. I did my own seals around the cover and never had any problem wasing the car since then as compared to the state before. So there IS a way to 'tune' the 'problem' in a very cheap way. :wink:

 

[UnhuZ]

Actually there is a seal (foam) around the cover but it doesn't keep the water out of the coil area. Also the rubber on the coil gets wider over time and makes them more sensitive to water. I did my own seals around the cover and never had any problem wasing the car since then as compared to the state before. So there IS a way to 'tune' the 'problem' in a very cheap way. :wink:

yes... there is a way....but not OEM....now i can empty a big can of water directly on top of rear cylinder head that not even a drop of water get to the bottom of the coils....

what i wrote is using only OEM parts as they were planned to be use...a 100% stock NSX

 

[WOODY]

I had a coil that was "weak". It operated fine under vacuum conditions , but when a larger load was pulled under boost it started to miss at about 5-6 psi.

 

[RON98]

chris is on the money, the coils are usually on or off.

dont worry about the cylinders not firing.

it will not result in any damage except maybe a little extra cylinder wall wear due to fuel washing the walls.

keep in mind the amount of preassure contatined by the engine under normal combustion is many times more violent then a non firing cylinder.

its like a body builder lifting 20lbs when they are capable of lifting 200. not much damage there.

congrats on fixing the problem.

happy motoring.

Rob :smile:

 

[angus]

Yes I'm also doubting the faulty coil was the cause of internal engin damage.
It would even take a long time for damage due to "fuel wash" to occur

 

[UnhuZ]

guys...sorry if this sounds a little bad....but...you guys doubt it...i'm sure.

the facts are:

1 - The engine was repaired and besides the 4 new valves on that cylinder, the only new parts was gaskets and the REAR COIL PACKS...

2 - Was not the valve adjustment, as it was perfect as were the other cylinders.

3 - Was not the injectors, as they were measured and were all within tolerances from eachother.

4 - since the event, the engine has done about 35000 milles of daily driving... and i don't spare the car...i drive like it was meant to be driven...hard.

5 - although the burnt valves, the cylinder head didn't needed any kind of treatment.

thoughts:

the burnt valves were due to heat above normal on that cylinder, this heat is due to bad combustion or fuel unburn that was ignited from flames coming through headers from other cylinder, etc.

you guys may doubt it, but then tell me what else would be the cause, because everything was checked and double checked so it won't happen again.

 

[stevetwors]

guys...sorry if this sounds a little bad....but...you guys doubt it...i'm sure.

the facts are:

1 - The engine was repaired and besides the 4 new valves on that cylinder, the only new parts was gaskets and the REAR COIL PACKS...

2 - Was not the valve adjustment, as it was perfect as were the other cylinders.

3 - Was not the injectors, as they were measured and were all within tolerances from eachother.

4 - since the event, the engine has done about 35000 milles of daily driving... and i don't spare the car...i drive like it was meant to be driven...hard.

5 - although the burnt valves, the cylinder head didn't needed any kind of treatment.

thoughts:

the burnt valves were due to heat above normal on that cylinder, this heat is due to bad combustion or fuel unburn that was ignited from flames coming through headers from other cylinder, etc.

you guys may doubt it, but then tell me what else would be the cause, because everything was checked and double checked so it won't happen again.

detonation, pre ignition, lean A/F. those are the only things i can think of.

detonation is usually when the engine is too hot and the fuel ignites on the outer edges (where its too hot) of the piston and that flame front collides with the flame front ignited by the spark plug in the center. causes a ping, marble in tin can sound. i dont think this does anything to valves though, this usually melts and deforms cast pistons. but nsx uses forged, but even with forged the problem is then the rings i believe? its also bad on bearings because of force applied unevenly or at wrong time/angle on the piston's stroke.

pre ignition is exactly as the name implies. this is bad for the crank/rod bearings too. burn is also too hot from this.

late ignition is much less worse than pre ignition. late ignition will have lower EGT, a cooler burn, less power. pre ignition, advanced timing, will give you more power, but at a risk because the burn is hotter. tuners try to advance timing as much as possible until it gets too hot and pings. they actually spark while the piston is still on its way up! the more advanced the timing, the slower burning fuel you need, this is what higher octane gets you, the higher the octane, the slower the combustion, allows you to spark even earlier.

i just realized im rambling. it sounds like most likely cause is lean A/F. When an injector starts to go bad, it sprays not enough fuel. this causes the A/F to be lean, which burns much hotter (and much more power). this is too hot for valves that are not made of inconel or titanium or whatever exotic pricey material. i know you said they ohmed out ok, but this test doesnt really prove anything, because that injector could have got gummed up or slightly clogged. a flowtest is the best test for injectors, thats the only way to know for sure, send it to RC. im willing to bet you $120 its a dirty injector that is flowing at 70%.

i dont see how a weak coilpack will cause pre ignition, maybe late ignition, which is not very bad at all.

im not an expert so id love to have the gurus correct some things i said above because i know im not exact 100% on this.

 

[FastraxTurbo]

Not to sound like an ass, but actually, most of what you have just said is incorrect. Preignition and detonation are two different things, late timing will raise exhaust gas temp and advanced timing will lower it. A weak coil will not change timing, but just give you a weak spark, thus possible incomplete burning of air/fuel and misfires.

 

[UnhuZ]

i don't think any of that apply on a stock engine and ECU...detonation appears from a lean AF ratio, and with a 100% stock car, i think it happens only if the injectors aren't pumping the right ammount of fuel....and that was not the case....