When to replace Ignition coils. (2 Viewers)

[mdcoa]

[mostly same material posted in "Spark Plugs Alert Alert Alert"]

'04 with 147k miles. According to Toyota records, PO had dealer replace plugs ~30k miles ago. I checked them a few weeks and they seemed pretty tight, but I noticed some of the coil boots looked TIRED, so ordered a Denso boot set and new TT plugs and one spare Denso coil for the glovebox.

Put new coil boots on, but could NOT get the new springs to go in, and couldn't find anything online about getting this style of spring to seat, so put the old spring back in (thankfully pretty easy). I recall reading about a tool someone made but couldn't for the life of me find it tonight--if anyone has tips, please share. Or if it's not worth bothering with, that's fine too.

I used a very, very small amount of dielectric grease on the inside edges of both boots per the Denso instructions (the kit came with a small packet of dielectric grease).

Only did the DS bank--plugs 1-7--tonight; will do the even numbers later this week. #1 had some oily looking threads and was probably a bit loose. All plugs looked pretty good otherwise, but the #5 and #7 boots were clearly getting old, and #7 tore while trying to twist it off. Must be a bit warmer at the back of the engine, causing the boots to age more quickly.

 

[95Fantasma80]

[mostly same material posted in "Spark Plugs Alert Alert Alert"]

'04 with 147k miles. According to Toyota records, PO had dealer replace plugs ~30k miles ago. I checked them a few weeks and they seemed pretty tight, but I noticed some of the coil boots looked TIRED, so ordered a Denso boot set and new TT plugs and one spare Denso coil for the glovebox.

Put new coil boots on, but could NOT get the new springs to go in, and couldn't find anything online about getting this style of spring to seat, so put the old spring back in (thankfully pretty easy). I recall reading about a tool someone made but couldn't for the life of me find it tonight--if anyone has tips, please share. Or if it's not worth bothering with, that's fine too.

I used a very, very small amount of dielectric grease on the inside edges of both boots per the Denso instructions (the kit came with a small packet of dielectric grease).

Only did the DS bank--plugs 1-7--tonight; will do the even numbers later this week. #1 had some oily looking threads and was probably a bit loose. All plugs looked pretty good otherwise, but the #5 and #7 boots were clearly getting old, and #7 tore while trying to twist it off. Must be a bit warmer at the back of the engine, causing the boots to age more quickly.

Is it possible you have NGQ coils and are trying to install Denso boot kit? I am looking at purchasing boot kit as well and wondering if I may run into same issue. Or is it just a matter of not having the proper tool to install the spring.

 

[dogdaysindurham]

I had the same issue with the new springs not fitting. The outer seal and boot fit fine. I have OEM and Denso coils.

The springs looked fine after 90k and had no rust or what not.

I think another poster used the NGK boot kit and the springs fit if I recall.

 

[mdcoa]

Ha—glad it wasn’t just me. I’m about 99.9% positive these are the coils this rolled off the assembly line with, so, Denso.
The original springs have a flat spot at the bottom coil, presumably to aid with installation, but the new ones don’t and the springs seem a bit wider at the base—I’ll measure when I do the passenger bank.
I can’t find it now but I recall someone saying he slotted a piece of brass rod from a hobby shop, but I remember having a hard tome visualizing it...if anyone has a killer technique and photos...

 

[nbailz]

Ha—glad it wasn’t just me. I’m about 99.9% positive these are the coils this rolled off the assembly line with, so, Denso.
The original springs have a flat spot at the bottom coil, presumably to aid with installation, but the new ones don’t and the springs seem a bit wider at the base—I’ll measure when I do the passenger bank.
I can’t find it now but I recall someone saying he slotted a piece of brass rod from a hobby shop, but I remember having a hard tome visualizing it...if anyone has a killer technique and photos...

It took me about an hour, but i was able to get all 8 springs replaced. I wouldn't do that ever again...no way it was worth it. There was nothing wrong with the original springs that i could tell. I used one of these sets linked below, and just kind of jammed the spring down with one and worked around it in a circle with another. 6 went in without much fuss (5 mins each?), but i had two that did not want to go in. You have to be pretty aggressive with them.

Amazon product ASIN B07QYL9KJT

 

[Eyedaho]

[mostly same material posted in "Spark Plugs Alert Alert Alert"]

'04 with 147k miles. According to Toyota records, PO had dealer replace plugs ~30k miles ago. I checked them a few weeks and they seemed pretty tight, but I noticed some of the coil boots looked TIRED, so ordered a Denso boot set and new TT plugs and one spare Denso coil for the glovebox.

Put new coil boots on, but could NOT get the new springs to go in, and couldn't find anything online about getting this style of spring to seat, so put the old spring back in (thankfully pretty easy). I recall reading about a tool someone made but couldn't for the life of me find it tonight--if anyone has tips, please share. Or if it's not worth bothering with, that's fine too.

I used a very, very small amount of dielectric grease on the inside edges of both boots per the Denso instructions (the kit came with a small packet of dielectric grease).

Only did the DS bank--plugs 1-7--tonight; will do the even numbers later this week. #1 had some oily looking threads and was probably a bit loose. All plugs looked pretty good otherwise, but the #5 and #7 boots were clearly getting old, and #7 tore while trying to twist it off. Must be a bit warmer at the back of the engine, causing the boots to age more quickly.

View attachment 2416486

View attachment 2416487

I installed the Denso springs by holding the them with needle nose pliers and turning them clockwise while pushing them in. This winds them up a little, and they go right in. Until I tried that, I had the same issue since the diameter of the end of the spring is a little bigger than the top of the hole. I think they do that so they're retained in the coil.
This took five minutes and a refreshment break to figure out, and then thirty seconds per coil to install. It was the exact same Denso boot set shown above.

 

[ouzo12]

[mostly same material posted in "Spark Plugs Alert Alert Alert"]

'04 with 147k miles. According to Toyota records, PO had dealer replace plugs ~30k miles ago. I checked them a few weeks and they seemed pretty tight, but I noticed some of the coil boots looked TIRED, so ordered a Denso boot set and new TT plugs and one spare Denso coil for the glovebox.

Put new coil boots on, but could NOT get the new springs to go in, and couldn't find anything online about getting this style of spring to seat, so put the old spring back in (thankfully pretty easy). I recall reading about a tool someone made but couldn't for the life of me find it tonight--if anyone has tips, please share. Or if it's not worth bothering with, that's fine too.

I used a very, very small amount of dielectric grease on the inside edges of both boots per the Denso instructions (the kit came with a small packet of dielectric grease).

Only did the DS bank--plugs 1-7--tonight; will do the even numbers later this week. #1 had some oily looking threads and was probably a bit loose. All plugs looked pretty good otherwise, but the #5 and #7 boots were clearly getting old, and #7 tore while trying to twist it off. Must be a bit warmer at the back of the engine, causing the boots to age more quickly.

View attachment 2416486

View attachment 2416487

Do you happen to have the part number for the coil boot? I was budgeting for an upcoming preventative starter change (smoking deal off of summit) and figured I would do the coils as well. Never thought about needing to replace the boot.

 

[Eyedaho]

Do you happen to have the part number for the coil boot? I was budgeting for an upcoming preventative starter change (smoking deal off of summit) and figured I would do the coils as well. Never thought about needing to replace the boot.

If you're ordering new coils, I think they'll come with new boots.

 

[2001LC]

New coils come ready to install no boots needed. Watch for boot leg

For those rebooting:
IDK, if spring a big deal. But I simple use needle nose pliers. IIRC I turn in reverse to start. Very easy!

 

[dogdaysindurham]

@ouzo12 I believe it’s Denso 671-8184 which comes with a set of 8. These are made in China.

NGK is CPB-T007 (is only for a single set) and was made in Japan but now made in China.

 

[mdcoa]

New coils come ready to install no boots needed. Watch for boot leg

For those rebooting:
IDK, if spring a big deal. But I simple use needle nose pliers. IIRC I turn in reverse to start. Very easy!

Ha! Makes me want to drive to CO and bring you mine--it'd probably take less time than doing it myself.

I installed the Denso springs by holding the them with needle nose pliers and turning them clockwise while pushing them in. This winds them up a little, and they go right in. Until I tried that, I had the same issue since the diameter of the end of the spring is a little bigger than the top of the hole. I think they do that so they're retained in the coil.
This took five minutes and a refreshment break to figure out, and then thirty seconds per coil to install. It was the exact same Denso boot set shown above.

I had no such luck--I tried needlenose pliers--twisting both directions with varying degrees of pressure--and teensy screwdrivers, and having my wife--who can see really well close-up--try it. I finally shoved the original back in, which looked pretty stinking good. . . . I may try the same experiment with the other bank tonight, but I almost wonder if Denso changed the design of the coil base slightly and the new springs only fit new coils, although if @2001LC has done this on a bunch of coils, lots of those were probably original . . .

Seems like everyone thinks this is very easy or nearly impossible--really a funny split.

 

[haryv]

As our 100 series fleet ages we're seeing more ignition coil failures. Is there a certain mileage or age where our 100 series with the 2UZ-FE engine are seeing the need to replace one or more ignition coils?

If you’ve replaced any coils please post any performance differences before & after, along with your millage, years in service and anything that contributing to the reason why you replaced them. Such as age, climate condition, bad spark plugs or improper gap, spark plug tube gasket oil leak, under or over voltage or anything you consider could be a contributing factor.

Sure we need to change coils when we get the P0300 series code suggesting a miss firing coil. Just swap coils to confirm code moves to different cylinder as expected, then replace bad coil. If not confirmed, then work through diagnostic tree.

In some cases we've seen coil replacement correct a poor running engine issue such as rough idle, without the CEL (check engine light) or any code being stored. Can it be that weak coils are robbing us of performance, but have yet to cross the point of giving a code. Would periodic testing with specialize equipment (see: Coil on Plug ignition video below) be a good PM, especially if performance or MPG drops.

Here are some questions to consider:

• What are some of the reasons for coil failure?
• Should spark tube gasket, seals & grommet be a PM?
• Should all coils be replace once one fails?
• Should we do a complete coil replacement as a PM at some point?
• Do coils weaken over time reducing engine performance, what the best test to reveal this?
• Aftermarket or OEM coils?

Edited 3/21/16 Toyota OEM (Denso) or Denso is best, cheap aftermarkets' are failing.
Rough Idle/Sputtering/CEL/Misfire = Coil pack problems
Understanding Multi-Coil Ignition Systems
Coil-On-Plug Diagnostics: Toyota Tundra - Tomorrows Technician

In the Autolite video below, it's recommend one determine cause of failure and correct it or reoccurrence is likely.



Seem to be three camps on the issue of COP.
1) Replace only dead coil(s).
2) Replace hunting for performance issue without CEL.
3) Replace all 8 as a PM.

Certainly replacing only dead coils will give tangible results immediately, for the least $$ at the moment of failure.

What I find most interesting, are the testimonials of performance issues (running rough and/or low MPG) long before code or CEL reveled a bad coil to be cause. Along with notable improving in performance with those that have replaced all 8. The implication here is, coils do weaken and rob engine of performance, before failing.

We've also seen a few reports of a drop in MPG after changing spark plugs. Could we be damaging coils while removing or could there be some issue with matching old with new??

Which camp are you in and why???

Technically they should never be replaced if you replace your spark plugs and the gap is within specs on the spark plug. as the spark plug Gap deteriorates and the Gap increases it put more stress on the coil and the coils voltage goes up. Current increases on the coil and the dielectric starts to break down in the secondary circuit. Eventually the secondary circuit I will short out. I would monitor the spark plug maintenance schedule more often and make sure the Gap is a little bit smaller than specifications. Also carry one or two inside the vehicle as spares.

 

[Eyedaho]

Ha! Makes me want to drive to CO and bring you mine--it'd probably take less time than doing it myself.



I had no such luck--I tried needlenose pliers--twisting both directions with varying degrees of pressure--and teensy screwdrivers, and having my wife--who can see really well close-up--try it. I finally shoved the original back in, which looked pretty stinking good. . . . I may try the same experiment with the other bank tonight, but I almost wonder if Denso changed the design of the coil base slightly and the new springs only fit new coils, although if @2001LC has done this on a bunch of coils, lots of those were probably original . . .

Seems like everyone thinks this is very easy or nearly impossible--really a funny split.

I put those springs into some original coils on my '99. I didn't think it was going to go until I got the technique figured out, and then it seemed easy.

 

[2001LC]

Ha! Makes me want to drive to CO and bring you mine--it'd probably take less time than doing it myself.



I had no such luck--I tried needlenose pliers--twisting both directions with varying degrees of pressure--and teensy screwdrivers, and having my wife--who can see really well close-up--try it. I finally shoved the original back in, which looked pretty stinking good. . . . I may try the same experiment with the other bank tonight, but I almost wonder if Denso changed the design of the coil base slightly and the new springs only fit new coils, although if @2001LC has done this on a bunch of coils, lots of those were probably original . . .

Seems like everyone thinks this is very easy or nearly impossible--really a funny split.

Bring it.

Or;
The spring is coiled in a specific directing. Turn in one direction and coil of spring expands. Turn in other direction and coil tighten, getting smaller. Turns so it get smaller as you push into coil. Once in, reverse direction about 3/4 to 1 turn to wind down in bottom. Done!

 

[2001LC]

Technically they should never be replaced if you replace your spark plugs and the gap is within specs on the spark plug. as the spark plug Gap deteriorates and the Gap increases it put more stress on the coil and the coils voltage goes up. Current increases on the coil and the dielectric starts to break down in the secondary circuit. Eventually the secondary circuit I will short out. I would monitor the spark plug maintenance schedule more often and make sure the Gap is a little bit smaller than specifications. Also carry one or two inside the vehicle as spares.

I like the TT plugs, as they start at 1mm gap. Which Denso claims they use less power. So coils runs cooler.

I've found, coils as they age, start delivering power at varying levels. They are not always "just" either good or bad!

 

[haryv]

I like the TT plugs, as they start at 1mm gap. Which Denso claims they use less power. So coils runs cooler.

I've found, coils as they age, start delivering power at varying levels. They are not always "just" either good or bad!

Its just a coil I have built a tesla coil same idea. The secondary uses I think varnish to separate the coil windings. Varnish has a given Dialestric Constant "cannot recall its value" The widder the spark plug gap, the higher the voltage goes on the coil. Eventually, if the plug is neglected and gap becomes large, the secondary coil will puncture through the dielectric and short out the secondary coil. I had a friend who fried 20 COPS because he was to pridefull to take it to a shop. The ECM dwell circuit failed and placed to long of a dwell time on the coils and that was what was cooking his coils. The ecu was replaced and resolved the issue. I asked him if he saved any money and he said no LOL

 

[silver02accord]

Walmart has the Denso for just under $54 with free shipping, bought 8 for pm and upcoming park plug change.

 

[mdcoa]

Bring it.

Or;
The spring is coiled in a specific directing. Turn in one direction and coil of spring expands. Turn in other direction and coil tighten, getting smaller. Turns so it get smaller as you push into coil. Once in, reverse direction about 3/4 to 1 turn to wind down in bottom. Done!

Thanks again, @2001LC . I had the DS coils out this weekend and thought I'd give these springs another try, using your approach. I'll be doggone if they didn't go right in. I had previously tried twisting in both directions--perhaps I just needed to be more confident while twisting counter-clockwise. . . .

 

[silver02accord]

Replacing spark plugs with Coils in the mail. Coils looked good (small crack in one) and boots and grommets were soft and pliable. Pulled coil #7 ds rear and wow. Swapping with #1 for now but this looks bad. Ok to run truck?

 

[2001LC]

Yeah, for now. The crack may or may not be meaningless to function. Those look like from spark plugs were walking out. The plug draw more volts heating coil, and the combustion gasses escaping cook them also! The heat is what kills the coils.