When to replace Ignition coils. (2 Viewers)

[sean2202]

"coil" is that an Denso coil, how'd you know which one to change?

I believe it is an original denso coil. I replaced the coil on the right in picture, it looked like it was starting to have a meltdown.
(other seven did not look like that)
Interesting side note had 7 Bosch
plugs and 1 NGK. Can't remember
if this coil was on the NGK or not.
Used denso coil 673-1303 from amazon as replacement.

 

[Battleship]

I replaced mine over the weekend at 165k. I was doing the plugs anyway, and they seem to wear out with vague signs of failure that can last for months before you see a CEL. I got aftermarkets, from DEAL electronics on eBay for $110 for a set. With 9 miles on them they are doing great. If they start to conk out they will get replaced with OEM.

 

[nmatcek]

155k on 2004 here. No CEL. I have a bit of a rough idle in drive. It comes and goes as the idle changes with the AC compressor. It's not bad enough to shake the steering wheel but it makes a deep bass sound through the cabin. No perceivable misfire during acceleration. For those that have had coils go out, how does this compare to your experience prior to getting a CEL?

 

[camino70]

155k on 2004 here. No CEL. I have a bit of a rough idle in drive. It comes and goes as the idle changes with the AC compressor. It's not bad enough to shake the steering wheel but it makes a deep bass sound through the cabin. No perceivable misfire during acceleration. For those that have had coils go out, how does this compare to your experience prior to getting a CEL?

That's about how mine felt before two packs died completely and threw a code.

 

[2001LC]

155k on 2004 here. No CEL. I have a bit of a rough idle in drive. It comes and goes as the idle changes with the AC compressor. It's not bad enough to shake the steering wheel but it makes a deep bass sound through the cabin. No perceivable misfire during acceleration. For those that have had coils go out, how does this compare to your experience prior to getting a CEL?

Assuming you've tuned the engine, keep up with PM and run a can of 44k through the gas tank. I'd say it's a good bet you'll see a failure of coil(s).

 

[Dwight S]

Good description. Slight stumble from idle up to around 1600 rpm when engine is cold. Mine usually went away after a few miles of driving. Last one got worse after a month or so. I have another going bad now. Same symptoms but also has a random arcing pop in the speakers until truck warms up and other symptoms disappear.

 

[calskibum]

I plan to replace my spark plugs this weekend, and after reading this thread, I realized that the slight stumble I've been feeling at idle may be a symptom of a coil going bad so I've just ordered some Denso ones from Amazon.

A quick question, what is the torque value for tighening the bolt that holds the coil to the engine?

Also, in another thread someone mentioned that you have to push down the coil hard to snap onto the spark plug. Can I assume that when the base of the coil is flush with the mounting surface on the outside of the engine, then it's properly seated with the spark plug? Or should I anticipate a noticeable click/snap in order to know that it's seated on the spark plug properly?

 

[Battleship]

Or should I anticipate a noticeable click/snap in order to know that it's seated on the spark plug properly?

I didn't get any kind of feedback that the coil had seated itself, either with my new aftermarket or when I was moving around my original packs. I wondered the same thing, but it's working.

 

[Clutchee]

2006- replaced all 8 coil packs and plugs at 258k.
Also replaced fuel filter.

No issues just pm to keep it running smooth.

 

[2001LC]

I plan to replace my spark plugs this weekend, and after reading this thread, I realized that the slight stumble I've been feeling at idle may be a symptom of a coil going bad so I've just ordered some Denso ones from Amazon.

A quick question, what is the torque value for tighening the bolt that holds the coil to the engine?

Also, in another thread someone mentioned that you have to push down the coil hard to snap onto the spark plug. Can I assume that when the base of the coil is flush with the mounting surface on the outside of the engine, then it's properly seated with the spark plug? Or should I anticipate a noticeable click/snap in order to know that it's seated on the spark plug properly?

Spark Plug torque is 13ft-lbf and gap of new is 1.1mm (0.043 in.), make sure to start threading plugs back in by hand. Many use a piece of rubber hose over end of spark plug as aid to starting threads.

You'll feel coil seat as you push in, and it's not necessary to push all that hard. Top seal of coil will contact valve cover at top of spark plug tube. When you torque bolt to 66in.-lbf (Yes that's inch not foot lb) it will compress the rubber seal at the top of coil a little.

Not sure other than replacing/swapping one at a time how you'll discover weak coil(s). I'm working on gather some old coils to run some test, just for this reason. If you can sent me your old coils please PM me.

 

[calskibum]

Thanks Buckeyefan and 2001LC. Right now I just hope that I don't find my spark plug well filled with engine oil when I pull up the coil. I've noticed some oil seeping out under the valve cover so the seal will need to be changed sooner or later. I hope by tightening the valve cover bolts it'll buy me some more time as I'm a newbie and don't feel confident in doing the valve cover seal myself yet. If a spark plug well is filled with oil, I'll have to wait on changing the plugs and coils until I can have a mechanic change out the valve cover seal. Of course that's getting away from the topic of this thread. keeping my fingers crossed on what I'll find this weekend.

 

[SNLC]

FYI, Amayama has OEM coil packs for $65ish

Search for Genuine Parts - Amayama Trading Co. Ltd.

Cheers

 

[suprarx7nut]

At 230k miles my cylinder 6 coil went out. With no warning the engine started running very rough and shortly after (3 miles) threw a P0306 code. I swapped coils with cylinder 4 and the problem code followed the coil. Easy diagnosis.

$57 via amazon for a genuine Denso coil: http://amzn.to/1XtEIdg

 

[brandon12777]

$57 via amazon for a genuine Denso coil: http://amzn.to/1XtEIdg

Just got one of these to have as a garage/trail back up

 

[85x]

Saw both of these on Amazon today:

673-1303 was $57.78 - Amazon.com: Denso 673-1303 Ignition Coil: Automotive
90080-19027 was $82.93 - https://www.amazon.com/Genuine-Toyota-90080-19027-Ignition-Coil/dp/B00FZMYD7O

Saving $25 bucks x 8 makes a big difference.... any thoughts on why the 673-1303 are cheaper?

 

[Battleship]

any thoughts on why the 673-1303 are cheaper?

My guess is that they are like the ones from Rock Auto, with the "Toyota" ground off the head. Maybe that batch didn't meet the QC standards Toyota has, so they get de branded and sold cheaper. They are still "Denso", just not "Toyota". I bet it makes little difference to us.

 

[suprarx7nut]

Saw both of these on Amazon today:

673-1303 was $57.78 - Amazon.com: Denso 673-1303 Ignition Coil: Automotive
90080-19027 was $82.93 - Amazon.com: Genuine Toyota 90080-19027 Ignition Coil: Automotive

Saving $25 bucks x 8 makes a big difference.... any thoughts on why the 673-1303 are cheaper?

673-1303 Is a Denso part.

90080-19027 is a Toyota part which they bought from Denso and must mark-up accordingly.

Toyota has to mark the product up to cover their overhead, and secondary manufacturing process (to add the Toyota logo and part number or at least to use that mold cavity in this case). This same principle holds true with ALL re-branded OEM parts.

The big car makers like Toyota make plenty of their own parts, but many parts are made by Denso, Aisin, Koyo, NSK, Timken, Nippon, Bosch, Delphi, TE, etc... You can buy the third party parts through the OEM (Toyota), but you are paying for Toyota branding and their distribution channels. Rock Auto, Amazon and other large retailers have FAR better distribution networks than Toyota, Nissan, Ford, etc... This allows for a significant price difference when comparing the same product.

This is a universal phenomenon with import vehicles from either Japan or Germany (and possibly other places). You can buy OEM always and get great parts - or you can figure out who actually made the part (rarely is it the OEM for non-body, non-cast metal pieces) and save on all that dealer markup, OEM branding and distribution short-falls.

My guess is that they are like the ones from Rock Auto, with the "Toyota" ground off the head. Maybe that batch didn't meet the QC standards Toyota has, so they get de branded and sold cheaper. They are still "Denso", just not "Toyota". I bet it makes little difference to us.

I'd be shocked if the Denso parts were rejects based on otherwise Toyota destined parts, but there is machining marks in the area where the Toyota logo would go. [shrug]

Anecdotal story: My previous employer made industrial measurement equipment. High precision, high dollar stuff. They also sold accessories to pair with it. Printers, Clamps, Hardware, Cables, etc... All of the accessories were literally just repackaged parts made by another company. Our contribution was solely a new part number of our own and new packaging. Zero value added, no testing done. We would buy accessory X off the shelf for $5 each and sell them for $50-100 each. The markup was purely made up to cover our extra, unnecessary re-branding and limited only by what we thought would drive too many customers away from our main product. Our OEM branding added nothing to the product, but in customer minds it added unbelievable value. We joked that we had a sickening license to print money. I had limited customer interaction unless they needed odd tech support or something, but I even told them they could buy part X online or in a store and they would just shrug it off and buy the re-branded stuff just to make sure it was the "right thing".

Another way to think of this situation is that Toyota, as a corporation, has no desire to just sell parts. They sell parts because they have to. If they don't sell parts then they can't sell what they really want to sell... CARS. This doesn't even take into account the dealers! The dealer, who you actually buy parts from, marks the product up AGAIN, usually 20+%, just to cover their operating costs and profits.

Wow, didn't expect that to turn into a novel. Sorry about that. Anyways... When you can determine the actual manufacturer of anything, buy it through them. I've never seen or heard any evidence that points to quality differences from an original source and the re-branded OEM.

 

[Battleship]

Yeah, who knows? I didn't even spring for the Densos and bought the totally cheap ones from eBay. They work fine so far (2 months) at $15 each.

My parents worked for GE a million years ago. They said that for some common parts, production runs with a failure rate of x would go to Japanese manufacturers, 2x would go to Americans, and 3x would go to parts stores. I made those numbers up, but that is why I made that assumption.

 

[hkeller]

239k miles on our 2000 LX on original plugs and still going strong. I will replace when they fail.

 

[2001LC]

239k miles on our 2000 LX on original plugs and still going strong. I will replace when they fail.

IMHO not a good idea as this can lead to coil failure. Cheaper to change 8 spark plugs then one coil. Additionally the longer plugs remain torque in the great the risk they'll freezes up. HF has a $10 spark plug cleaner, works great with air compressor set at 85 PSI for 20 seconds. I'd pull plugs, clean and test to FSM spec at minimum.