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06 DC SR5 White
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Discussion Starter · #1 ·
Why is it that the 6 cylinder, 4L engine (1GR-FE) is the only engine that requires replacement of spark plugs every 30,000 miles. All other Toyota engines are scheduled at 120,000 miles.:sosad:
 

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WOW 120,000...I would never do that anyway
I changed them every 30-40,000 anyway on my other 2.7 taco.
I dont get the big deal either..they are what 2 bucks each
 

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3SGTE & 1GRFE
MR2 Turbo, Taco Dcab
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793 Posts
Kneebiter - i wouldn't be giving out advice like that. have you ever stopped to think what happens with excessive plug gaps?

long story short, it burns out ignition coils. i'd rather replace plugs than coils anyday. it's not like plugs are expensive or hard to change.

personally, i'll be following the service schedule because i'd like my truck to last for many years after i'm done paying for it. do what you will with your own. :)

-Mike
 

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Tacoma X-Runner
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doesnt the x-runner come with iridium plugs? ( w/ the 1gr-fe)
i think they cost a little bit more, but i dont remember the price
( i havent used them since my integra type-rice)

they will easily last 20k-30k miles though if your engine is in good shape
120,000 miles is unheard of???
 

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Toyota Fanboy
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4,486 Posts
I replaced the factory original spark plugs in my F-150 at 110,000 miles and they were still well within specs.
You can easily get 120,000 out of a set of spark plugs nowdays, especially with double platinum and iridium-tipped plugs.
30,000 seems a little excessive to me, but if thats what Toyota says to do, Id go with that.
By the way, the Deno Iridium sparkplugs are not $2-$3, they are more like $8. I use them in my snowmobile and they arent cheap, but they last a really long time.
As far as excessive plug gaps burning out coils, thats a new one! :dunno:
 

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WAX museum.
2005 Tacoma
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1,390 Posts
Captain_Toyota said:
As far as excessive plug gaps burning out coils, thats a new one! :dunno:
Agreed. The coil puts out a definte amount of electrical current regardless of the gap.
 

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3SGTE & 1GRFE
MR2 Turbo, Taco Dcab
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793 Posts
electicity tries to find the easiest path to ground. i think you're all familiar with that. when you have excessive plug gaps, yes, the coil can fire the plug still, but once you start getting up to the point where you have 30KV+ required voltage (the amount of voltage required to jump the plug gap and fire the cylinder), it starts grounding through the coil body, causing carbon tracking and dielectric leakage. it's not the current you need to worry about. i'm not talking about "overheating" the coils. it's the voltage.

once you have carbon tracking in the coil, the problem only becomes worse, until a point where even if you change the plugs and have the correct plug gap, the carbon track through the coil body will have less resistence than the plug gap, and the coil will no longer fire the cylinder, no matter what.

i didn't feel like typing all of that out the first time, but since i now feel it wouldn't be wasted typing... :)

-Mike
 

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The 4L doesn't have the iridium plugs, therefore the recommended 30,000. Iridium is good for 120,000 no problem, gap doesn't change and is factory set.
 

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WAX museum.
2005 Tacoma
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1,390 Posts
NESW20 said:
electicity tries to find the easiest path to ground. i think you're all familiar with that. when you have excessive plug gaps, yes, the coil can fire the plug still, but once you start getting up to the point where you have 30KV+ required voltage (the amount of voltage required to jump the plug gap and fire the cylinder), it starts grounding through the coil body, causing carbon tracking and dielectric leakage. it's not the current you need to worry about. i'm not talking about "overheating" the coils. it's the voltage.

once you have carbon tracking in the coil, the problem only becomes worse, until a point where even if you change the plugs and have the correct plug gap, the carbon track through the coil body will have less resistence than the plug gap, and the coil will no longer fire the cylinder, no matter what.

i didn't feel like typing all of that out the first time, but since i now feel it wouldn't be wasted typing... :)

-Mike
That's pretty interesting... Especiacially since engines have different coils and gap requirements. So this 30KV number....... Is this unique to the 4.0 or what? Because I've had bigger draws than that on a turbo aircooled engine that didn't result in coil failure as it was designed to do so with a corresponding Mallory ignition coil...

Interesting topic though, I'm interested to learn more...
 

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06 taco 4x4 sport ac
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114 Posts
check your owners manual. Its a requirement to keep the federal emmision warrenty.
 

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3SGTE & 1GRFE
MR2 Turbo, Taco Dcab
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30KV is a rough number for most applications. there are exceptions to every rule. :) "normal" required voltage on an n/a engine is usually around 10-12KV. curious, what was your other engine in? baja car?

-Mike
 

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The main reason for replacing the plugs in the V-6 is it has aluminum heads and the plugs will "weld" themselves to the head unless anti-seize lubricant is installed. Removing a seized plug is something you don't want to experience.
 

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Steelheart said:
The main reason for replacing the plugs in the V-6 is it has aluminum heads and the plugs will "weld" themselves to the head unless anti-seize lubricant is installed. Removing a seized plug is something you don't want to experience.
The 2.7L has aluminum heads too. As said before, the only reason for 30,000 interval in the V-6 is non-iridium plugs. :confused:
 

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3SGTE & 1GRFE
MR2 Turbo, Taco Dcab
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793 Posts
Steelheart said:
The main reason for replacing the plugs in the V-6 is it has aluminum heads and the plugs will "weld" themselves to the head unless anti-seize lubricant is installed. Removing a seized plug is something you don't want to experience.
make sure you use anti-seize that is metal based. conductivity = good.

-Mike
 
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