March 29

2003 Honda Accord, Spark Plugs and Ignition Coils



Mark: It's Mark from Top Local. I'm here with Bernie Pawlik, Pawlik Automotive in Vancouver. Vancouver's best auto service experience. 23 time winners of best auto repair in Vancouver as voted by their customers. We're talking cars. How are you doing Bernie? 

Bernie: Doing well? 

Mark: So 2003 Honda Accord had a problem what was going on with this vehicle? 

Bernie: Yeah, so the client brought it in, it was due for a maintenance service and she had also noted that the engine was running rough under certain conditions. 

Mark: So how do you go ahead to proceed and test and diagnose what was going on? What was the actual problem? 

Bernie: Yeah, so we road test the vehicle and we could confirm under, you know, a bit of a load condition, the engine was running roughly, like misfiring. And that's the first step. So we got our diagnostic scan tool, that'll help us get in the direction of which cylinder the issue might be occurring in. If there's a misfire.

So we look at the data on the scan tool. We scan for codes and found, there's actually a code for misfire in every cylinder. So when there's a code, usually it comes up as P something. And so P03O1 , for instance means cylinder number one, misfire.

And it's interesting when they use diagnostic trouble codes or set up certain  codes, mean certain things like a 300 series code is an engine misfire code. A 400 series is an emission systems code. So it's kinda well-organized but anyways, there's a number of codes for a cylinder misfires, all of them in fact, not just one. So that made for some interesting next level testing. 

Mark: What exactly is a misfire and how do you determine what's causing said misfire? 

Bernie: When an internal combustion engine is running and you could have anything from I mean, I think about in cars, what we found is, you know, 3 cylinders kind of the minimum that you'll find and 12 is usually the maximum. And any of those cylinders every time they go through their cycle, they're supposed to fire as a spark and it's supposed to work. You know, it's supposed to fire a good combustion cycle and if it doesn't, the vehicle computer through a, usually a crankshaft position sensor, the speed of rotation, will figure out, Hey, that cylinder didn't fire properly. You can also feel it usually. 

Sometimes you'll get misfire codes where you don't feel any issue, which can sometimes be a sensor problem or something else, but normally you'll feel a roughness in the engine. It just isn't performing properly. It shakes or shutters, something happens. 

So the misfire is basically a combustion event that did not occur. And there are a number of reasons for it. It can be anything from like bad compression of the cylinder, or it may be a valve is burnt. It can be a spark plug that isn't firing and ignition oil, computer problem, fuelling objector intake leak. There's a number of things. And misfires can happen at low speeds or high speeds. So there's a number of causes. So I think he had a two-part question. What's a misfire. And what was the other question, Mark? 

Mark: How do you determine what's causing it? 

Bernie: Yeah, so how do we determine? So we basically go through a tree of items to look at, first of all, and a lot of is based on our own experience.  I've worked on cars for my whole adult life. I can usually tell by driving along, yeah. It feels like an ignition misfire. It feels like the spark plug somehow just didn't fire that spark. There's just a certain feel to it. Which can, it's not a hundred percent accurate, but a lot of times I find it could be 95% accurate, but there are things we can test. And usually the easiest area to start with is ignition system. 

This has an individual ignition coil per spark plug. It's a six cylinder engine, so we can transfer spark ignition coils around this specific cylinder. What we did is clear the codes and we're able to narrow it down to a couple of cylinders that it seemed to be more common causes.

So we swapped ignition coils around between the different cylinders and the issue followed those ignition coils. So then we know that coil is the problem. Also, when we removed a spark plug, you can see they were pretty old. So again, that was something we suggested to do as a repair as well.

Mark: So I don't imagine it's, because they're fairly accessible most of the time. It's not that difficult to job. Replacing spark plugs and ignition coils. 

Bernie: On this Honda Accord is actually a pretty straightforward job. We're lucky here because a lot of V6 engines have an intake plenum that hangs out over the back of the engine. So the rear cylinder bank is very hard to access the spark plugs and coils. And you often have to remove the upper intake manifold to take those apart. So it can be quite a bit more time consuming. 

On a Honda they've nicely put the intake plenum square over the centre of the sort of V of the engine. So it makes for a pretty straightforward replacement. And we have pictures here. We can actually look at some stuff. Let's have a look at some pictures. 

So there's our, there's our 2003 Accord. It's a 18 year old car, but still in pretty nice shape where you can see a little scuff on the bumper here. If you look close enough, but still nice and shiny and  in good condition. 

2003 Honda Accord, Spark Plugs and Ignition Coils

There's the front cylinder bank of the engine. So again, it's a V6 engine. There's three ignition coils. The rear is kind of like, looks like the same. And fortunately as say you can access it.

2003 Honda Accord, Spark Plugs and Ignition Coils
2003 Honda Accord, Spark Plugs and Ignition Coils

The other thing about this car too, is it has more of a longer hood than you find a newer cars that can often make it difficult to access the coils in the rear as well. But fortunately, on this car, it's not too difficult. 

And there we have the old ignition coil and spark plug, you can see the spark plug, there's a fair bit of corrosion above the, usually you get, you find these after awhile, there's probably a tiny little bit of combustion gas leaks out through the porcelain of the spark plug, not a big issue, but it kind of indicates it's been installed for awhile. These are probably original spark plugs. Hard to be a hundred percent sure. 

And there's one of the old coils again, you can see a bit of corrosion that just kind of common on coils, but you know, inside they're magnetic windings and things that just tend to wear out or they could be cracks that can develop down this tube here, which could cause spark to leak out into the the surrounding the metal of the valve cover. There's our picture show. 

Mark: So why not just narrow it down to those two coils that you found were bad and change all the plugs, but just those two coils? 

Bernie: Well, that's certainly a possibility. And one thing I will say is when the vehicle was brought in and had a misfire in all cylinders. So that doesn't necessarily mean that they're all bad, but they could have all been bad at some point in time, or sometimes, you know, one or two cylinders will cause all of them to misfire.

Sometimes just clear the codes and see what reoccurs, what's happening right now. But anyways, to answer your question, you know, it's a mathematical thing sometimes. How much did the coils cost? How much time does it take to diagnose the issue? How old are they? If two have failed and the vehicles got 165,000 kilometres, how likely is it that the other four are on their way out? If two or three have failed now or getting weak. 

And then the question is if you can narrow it down to those two specific coils and we do have other ways to test besides swapping coils. We can hook it up to a lab scope. We can actually look at the firing patterns of the coils and see how they're firing. But besides that you know what happens in a month or two, and we've had this happen where we've had a vehicle, say it's a four cylinder, easy to change a coil. Hey, just change one. We found one that's bad then. A month later, the customer's back, Hey, the engine's running rough. Then you have to redo the diagnosis. There's a cost there. 

So I think it's better, we do them all. You know, we have a, usually a two-year warranty on these items. So customer has a two year warranty it's done, you know, finished anything happens, say a coil goes bad. They're still covered for two years.

So you know, whereas if we do just one or two and then, Oh, that one, you know, there's another one that's bad, there's more diagnostic fees and more testing. And it just makes sense.

Now the only time it may not, if you have a vehicle with a very expensive coil, I used to own a Subaru with an H six engine, very expensive for the coils in this engine, because it's not a common engine. So. I had one that failed. I just replaced one because it was so expensive to change the coil to do all six would have been a couple of thousand dollars in parts. Kind of ridiculous. So you just gotta do the math and figure it out, but usually it makes sense to change them all once the car gets old. 

Mark: And that's based on, like you said, pretty much your entire adult life working on cars and having gone through every other possible way of doing this to try and save money for people and finding that the best way is sometimes the easiest way. 

Bernie: Yeah. And when you think of it from a maintenance perspective, again, you know, I love aircraft maintenance because they fixed stuff preventatively because they can't really afford an aircraft engine to fail while you're mid flight.

So you're thinking, well, why would you want your car to do the same thing? Yes, it does cost a little more money to do that, but it makes your driving experience overall a whole lot better and more enjoyable. More peace of mind. You know, this is time to change the ignition coils. They've run their lifespan. This is time to do them. 

Mark: Basically save your frustration for all the other parts of your life. 

Bernie: That's right. Exactly. Exactly. But if your car runs well, that part's easy. 

Mark: You mentioned this vehicle has 165,000 kilometres. Was there any other service due at this time?

Bernie: Well, there's a couple of things. One thing we did do, and this isn't in the Honda schedule, we did a motor vac fuel injection cleaning, which is something we recommend every two, three, four years on a vehicle, depending on how much you drive it. So we did that during this service, which made a lot of sense, considering the engine had been misfiring and we'd never done one on this particular vehicle. This person's owned the car for a few years. So we did that. 

But the other you know, schedule maintenance item is the timing belt. This engine does have a timing belt that's due about I think 165 or 168,000 kilometres. So we didn't do it this service. But we will be doing it in the near future. So that's kind of the big service item on a Honda and actually spark plugs were actually due at this particular time. So it's a good time to do it all. So timing belt coming up next and that's kind of the major Honda item. 

Mark: And how are these, this is an 18 year old car? How are these age of Accords for reliability? 

Bernie: Yeah, that's a really good car. Now it's funny talking about reliability for a car this old, but at least we've had 18 years of experience to see what kind of a car it is. And the automatic transmissions have been a problem on Honda's of this sort of earlier, early 2000 generation. And I'm not sure if this one's ever had the transmission replaced, it works fine at this point, but that's definitely a problem that's happening. And often they happen, you know, fairly early on in the life of the car, in the five to 10 year old range of the car. So I consider that to be kind of a bit of a problem, you know, for reliability. But other than that, they're good cars. I mean, there's the expense of the timing belt, which a lot of engines don't have, but at least that's a predictable expense.

Whereas say a timing chain failure is a non predicted expense and a lot more money. So overall, you know, I think they're excellent cars. You know, do you want to buy an 18 year old car at this point? I mean, if you're looking for an older car, that's probably well priced. They're still reliable if you can get one that's well-maintained. 

Mark: If you're looking for service for your Honda in Vancouver, the guys to see are Pawlik Automotive. You can reach them at (604) 327-7112 to book your appointment, or you can book online on their website, Of course, if you want to see us in living colour, there's hundreds of videos on there all makes and models and types of repairs.

Check out the YouTube channel. Pawlik Auto Repair. We've been doing this for nine years now. There's hundreds close to a thousand videos on there, actually of all like I'm serious, all kinds of vehicles. All types of repairs. Thank you so much for watching. We really appreciate it. Thank you, Bernie. 

Bernie: Thank you, Mark. I'll have to crack a bottle of champagne open when we do our thousandths video. 

About the author 

Bernie Pawlik

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