Coil Pack Failure?

Why do you suspect defective coils; any symptoms or codes?

What’s the miles?

 

Swap coil packs with another cylinder and see if your misfire follows.

I've never had more than one fail at once, but sometimes within a few months of each other. Used ones are a minor gamble, all depends on the price really.

I've learned through trial and error that there are many low grade counterfeit ones on the market, sold in convincing packaging with all the right brand names and marks. Amazon and eBay are full of counterfeits.

Also learned that the counterfeits work fine, at first. But they tend to fail after a year or two instead of 10-20 like with the real deal ones.

 

When you removed the intake manifold did you clean it, in particular the small diameter (4~5 mm) EGR passages, one at each intake port?

Also, did you follow through on cleaning the EGR components? (you had a previous thread, prepping to do that)

your miles reported in previous but recent thread, are around 108,000? That’s somewhat early for head gasket to fail. If you haven’t done a full EGR clean I would, soon.

Also keep an eye on engine coolant level in the reservoir, and consider doing (or getting done) boroscope inspection and/or leak down test.

Regarding the coils, there’s no codes, and your main reason for suspecting them is you’re experiencing occasional rough running. May be a red herring.

 

This is kind of exactly what's going on with the 13 persona right now with the description you posted of how your car is running The torque plate business and all that I'm about to get the transmission out and have a look and I have my old original transmission on standby as well as two torque plates and the flywheel that the torque plate bounce on I'm banking that either The plastic pieces in the springs have been knocked out of one or two of these springs The flywheel portion the six or five bolts or whatever something's loose possibly I have no idea but I will say on the video that I have posted on wherever it is I can send the link it's on my YouTube I think under my same name here You see my engine running absolutely stupidly smooth while the racket between the engine and the transmission where your eyes immediately focus to is just wild n out.. I wish I could find a mess I have aftermarket junkie coil packs as most people here might call them and they seem to be spot on the plugs and all the ignition seem to be firing absolutely perfectly You can see it in the video If it was an older style car and I was lifting the plug wires off of the plugs you would hear the drop and all the funny business like you did back in the day of course doing that to this vehicle You might damage the coils If I thought for a minute I had bad coils there are aftermarket very nice coil over plug units made by some Asian company they work out to be I don't know what about $44 a pop they're like billet aluminum and so on and so forth have pretty good warranty on them they're called out for our cars and many others Hondas Toyotas some GM maybe even two they've sent me advertisements to my business address several times I think they're red I can't think of the name they look like they do a good job and maybe doing a good business and then there are others I wouldn't think coilover plug technology is anything we need to really super worry about needing any kind of super high quality of course you don't want junk so far the aftermarket coil set that I bought for my Gen 3 which look very much like the factories seem to be working fine have no problems and the wells that they sit in are clean but I have the same clunking business you do right now and it's been this way for a few months we've not been driving the car I'm worried about that clunking and clanking rattling everything to death We have plenty of cars so that's not a problem. But my next move is to get the transmission out and have a look behind it maybe put the transmission that was originally in the car which was working flawless when the engine blew up We will see. And good luck. We will phase out our Gen 3's as they fall by the wayside and we're back to four generation twos and may have one or two more any minute

 

Every engine control unit has its own thresholds for misfires, but they can all have misfires for a while without actually logging a P030X code. At some point it gets worse and then codes are trapped.

Until that happens, you kind of have to go by older methods.

One such: selectively unplug one coil at a time, and do a test run. The engine should feel like it is running on three cylinders with the bad coil disconnected. It will run worse than on three cylinders (or perhaps not at all) when one of the good coils is disconnected.

Look for carbon tracking. In many cases the failure mode is high voltage leaking. The spark is occurring, but it's happening between the coil and the inner wall of the tube it lives in rather than at the plug gap. Sometimes this leaves observable burns and carbon dust. I haven't had much luck with this method, but others do okay.

That's a heat harvester. Keeps the engine coolant warm by flowing exhaust over it. Faster warm-ups, so the engine burns less fuel getting into its most fuel-efficient temperatures. Good to keep it happy.

 

I understand it to be a running measurement of crankshaft position. A Prius is well-instrumented to know exactly where the crankshaft is within its circle, and if it suddenly seems to be behind schedule (due to misfire) the ECU can mark the event as a misfire if it is severe enough. But I couldn't tell you what the tolerance is or how to read it from your diagnostic tool.

You're correct, swapping two coils is useful if you already have a suspect meaning a misfire severe enough to leave a code, and considerably less so if you don't. Swapping in a 5th of any origin will eventually help you puzzle it out.

 

You need a code reader to tell you where the missfire is first.
If it's #1, and switch #1 and 4, and clear the codes and the missfire moves to #4, then you know it's that coil.

 

Have you pulled the plugs?
Have you check your fuel quality? Maybe you got some bad fuel.
Take a sample and put it in a clean clear jar. Wait 5-10 minutes and see what
it looks like.
It is possible you have a bad connection at the packs. If they injectors are clogged,
they likely won't be producing a mist pattern. And if the droplets are too large they
don't burn fully or quickly. Which could cause a hessitation. And might not show
as a missfire because the coil and plug are firing correctly.

 

I thought it was crazy to blame ignition coils for engine problems for decades... But have fixed Prius by replacing ignition coils, so it really is a thing. But kind of embarrassing that Toyota can't build such a simple electrical circuit without such a high failure rate.

 

To see if there actually are any misfires, hook up Techstream, put the vehicle in maintenance mode, and switch to Engine and ECT > Live Data List. Monitor the misfire counts for each of the cylinders. Anything more than 0 is an anomaly, and then you can swap components between cylinders to see if anything changes.

 

I look at it like I'm coming up at 300K on three of these cars win some misfires start to develop some of mine I have NGK coils in place of the denso units on same engine so they've been worked on and dealt with before now while I have the car. When the misses start to show up I'll just get new coil sets put in new plugs and start there nowadays there's some really nice coilover plug manufacturers that seemingly do good work so it's probably just worth it to do that they're not that expensive The ones I bought for the Gen 3 were like $88 for the set and I was extremely skeptical but when they came the packaging was decent The material and workmanship looks good I can't see the circuit inside. And they've worked flawlessly for about 2 years so I'm okay with it.

 

The primary is also pretty much impossible to check, by any simple 'resistance' or 'diode' check. No connector pins expose the coil directly; you're trying to make those measurements across what turns out to be a more complicated electronic circuit really.

 

Do you know why they went from a single coil to 4 coils? The single coil systems of all my old cars seemed bulletproof? Why do these weaker coil over plugs fail so often?

 

Yes but then you have to have a mechanical distributor well generally speaking or you have a four coil pack mounted to the side of the motor and four wires running up to the extensions and to the plugs I guess is another way to do it general motors. But generally these coilover plugs were talking about these it well over $170,000 mi usually and usually really over 200 for the most part or right in that range I buy cars a lot and see coils have been replaced NGK is a popular brand so I have the gray NGKs on one or two cylinders and the black denzo on the other two now whether the change was really needed or not I have no way of knowing a lot of these cars people just pull the parts cannon and start firing which can be problematic I guess but it seems the coilover has taken over and is the way to go The failure rates don't seem to be really that high they just seem to be pretty steady and it pretty high mileage when most people have long gotten out of the car because of whatever reason.