Coil Pack Failure?

I guess economy. Better maintainability. Instead of replacing a whole pack you replace just one coil. Although, theoretically, if one fails the others should fail since they age at the same rate? But in the real world that would never happen, which is why it's like this I guess.

 

Well I"ve bought a set of 4 used but genuiine coils off of ebay, they'll either make a difference or not, if they don't I'll send them back or resell them.

But TBH, two of my coild have their outer dark metal bit rusting and corroding since I didnt have the plugs all tight for a couple od weeks. I'll be interested to see the results.

 

I don't, but the seller claims they're tested as working.

There's three ways this could go:

• Confirm that the problem was indeed a coil/coils if the car runs better.
  • But I'm with Medel on this, it MAY not be them, but who knows.
  • I need two new ones anyway as combustion leaked up the side of two of them recently because I didn't tighten my plugs properly.
• Confirm that a coil/coils were NOT the problem because the car runs exactly the same with the same symptoms.
• Confirm the seller lied about testing them because the car runs worse, at which point I'll send them back for a refund with video evidence.

 

Just to report... the car is still the same after swapping all 4 coil packs over for 4 completely different ones.

I guess this shows two things:

• The problem with the car is NOT the coil packs.
• I probably didn't buy defective used genuine coil packs.

Next on the list is redoing the cleaning of the EGR system, but to actually take the heat exchanger off and do it properly and not be lazy. That won't be for a little while though, sadly.

For now, I'm defeated.

 

I've had the Torque Pro app on my phone reading the OBD2 port while I drive, and there are no misfires on any cylinders ever. Never seen a fault code on the car. I assume this is the same as what Techstream would see.

All I'm concluding at this point is the fact that It pretty rough while charging when it goes to two bars. Presumably because the engine is providing more torque at lower speeds (i.e more fuel, like when an engine is cold and it needs to run richer). So going to explore fuelling next.

It's a horrid bag of spanners when driving at low speeds (moving in a traffic jam for example) while it's charging (when it needs to move from two battery bars to three). It'll switch from moving with the batteries, to switching to charging the battery from the engine and moving wiith the motor also charging the battery. I'd then slow down, engine stops and it regenerative charges, i'd come to a stop and then engine starts up and wants to charge without moving, but withing seconds I'm needing to move, engine kicks in, and it just painful.

I veering towatds a fuelling issue now. What values should I look for in terms of fuelling in normal mode vs charging mode and moving off from a standstill.

As always, I really appreciate the dialogue.

 

Yea this is what I've gathered, I monitored it all on the way to work this morning. There wasn't much life from the EGR system, presumably because my engine coolant temperature never got about 75oC. Does EGR valve start working at over 80oC or something?

 

I've "probably" worked out what item is causing the issues on my car. I haven't come across this issue in this forum before, so bear with me.

This morning I went under and I sprayed this valve type thing on the exhaust near the second catalytic converter with WD40 and the symptoms lessened.

When I say the symptoms lessened, it starts the engine a LOT smoother, because, for months now, there is ALWAYS a clunk as the engine kicks in (and shuts down for that matter)... whereas when I bought the car (nearly 3 years ago), when the engine started it was barely noticeable in 'Park', and when on the move if the engine got started to helping the motor move the car or charge the battery it literally unnoticeable other than the extra engine noise and the feel of assisted acceleration. It was silky. Another thing that's pretty much gone is when it's charging at standstill, idling in 'Park'. While driving, it's start the engine and transitions fine, and it does still rattle while on the move, presumably because everything is moving with applied torque and power to the wheels, but it is genuinely much, much better. The real acid test for me now, is when the traction battery drops down to 2 bars in slow moving stop/start traffic because THAT is when it's a real bag of spanners! But I kid you not, the difference is real and I'm not hallucinating!
So what I'm going to describe below may sound a little misunderstood from my perspective and Prius knowledge, technically illogical but scientific, even controversial and coming across as complete nonsense to some. But bear with me here because it can't be a coincidence, I swear I'm not hallucinating.

Thinking back to last year, when I cleaned out my EGR system, because of similar symptoms, I also did this same 'quick fix' to the valve in the exhaust and it also worked better again at that time, albeit for a short amount of time, so I didn't think much of the fix and dismissed doing it again because of the ambiguity of whether it actually worked or whether it was a coincidental result, and it's under the car. So the problem at the moment is the ambiguous nature of what this valve thing in the exhaust and how it's the root cause of the symptoms I'm experiencing. But I'll offer my thoughts, and I'll be interested to hear your thoughts, some of you will dismiss it as pure fantasy, other may agree, and others will want to understand more.

Bear in mind that my Prus is an UK based European spec vehicle. I read somewhere that the exhaust pipes can have different ancillary add-ons depending on the regions of the world the car was sold to.

I understand that all Priuses have the coolant fluid going down to warm the catalytic converter up to make it more efficient and less polluting? I'm also led to believe it may also work the other way round, whereby the coolant flows to warm the engine up quicker when the catalytic converter get to a hot enough temperature that can help warm the engine? Unless this is what I think this special valve does? Either way, they all have these types of mad features to squeeze as much economy out of the system as a whole.

I'm sure I read somewhere, that some Priuses (specifically UK ones) have this 'other' thing that has to do with reducing noise levels? This may or may not be part of the same assembly that helps to warm the engine up using hot exhaust gases. As opposed to the EGR system where by exhaust gases are diverted to a cooler to help recycle exhaust (but that's another tangent).

But this valve thing I'm seeing seems to be some kind of extra baffling that can be introduced in and out of the exhaust flow to control noise levels? Because noise is also loss of energy too! So again, it's an efficiency thing. The whole exhaust 'assembly' add on thing has the coolant pipes coming in and out from up from the front towards the engine. This is where the US cars may be missing a feature, but there's this 'mechanism' where there's a shaft being pushed by a piston attached to a spring loaded hinge that goes up into the exhaust pipe presumably with a flap inside which has the additional muffling to quieten the exhaust noise and therefore save 'energy'. Again, I don't think all Priuses have this other additional thing, but mine seems to have it.

So if this valve is unable to work to it's full range because it's dirty, dry, corroded, stiff or stuck it would have an effect on the harmonic flow of the exhaust gases thus causing an unbalance in the cylinders as the valves work, therefore leading to what seems like a misfire, but in reality, it's more of a harmonic unbalance in exhaust back pressure, probably not helped by the fact that the engine works more in the Atkinson cycle (presumably controlled by the variable valve system)... Could the above waffle be the root cause of the mechanical unbalance in my engine, which in turn causes the damper plate to vibrate?

 

I did buy a two hour subsrciption to Toyota TIS this afternoon and did see those pages. So your quite right to call me an armchair speculator.

So now I know it, and what it does. I'm going to spray the mechanism again in the morning, might pop the spring off and lube the shaft the flap is on, and make sure it moves freely. It might be a bit crudy to move, or the spring has rusted up a bit on the inner turns it's coils. I'll also run the engine and watch for the shaft coming out, and how hard it pushes. I'm not disputing you saying it pushes hard. Could the thing fail in some way? Could the wax leak or age or harden or soften? I assume I could verify if the water actually gets to it by feeling the water pipes? Maybe it's time to change the fluid? Crud might have collected and settled down there? Anyway, I'll post back again tomorrow when I've been back under it.
Thanks ChapmanF.

Back with an edit. Question.

Could I take this thing off by clamping the coolant hoses (as opposed to draining the whole lot) to check the condition of the bung, gasket, etc?