Denso Platinum TT for 2004 Corolla?

Z

zorobabel

Joined
Jan 27, 2011
Messages
1,231
Location
Roseville, CA
For the past 10-15k miles the Corolla seems to crank about a second longer to start. Battery was changed last year, and it is running NGK IFR5T11 spark plugs (100k on them so far, 120k is recommended).
I've got the spark plug change itch
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and my justification for the change is that it will help start the engine faster
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.
I'm thinking of trying the Denso Platinum TT (PK16TT) this time and changing at 50-60k. Partly because I'm still sore about paying $15 per plug on the NGK Laser Iridiums years ago (though prices have come down a lot since then). I could also go with the Iridium TT (IK16TT), but I like the idea of changing spark plugs more often: less chance of getting stuck, better if fouling occurs, some say resistance degrades on old plugs.
The TT range has a tip on the ground electrode, which I like as it would make measuring the gap easier. In the case of the Platinum TT, the center electrode tip is Platinum while the ground electrode tip is Titanium. The PK16TT laso has a 0.040 gap compared to 0.044 for the IFR5T11. Though I have to say that the original IFR5A11 I pulled at 97k measure 0.041 with stacked feeler gauges.
Your thoughts please?
 
Use iridium. They will not get stuck
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The 100k NGK's you are about to pull out will not be stuck, either. They will come out with no problem.
 
I'd run the iridiums just like it came from the factory. Buy them from Amazon. I've changed out the starters in both of my Corollas at about 120k miles. i'd be more inclined to think it's the starter instead of the spark plugs causing delay in starting. Pretty easy to change the starter in that engine. Either remove the intake manifold and replace the intake manifold gasket or remove one of the radiator fans so you have access to the starter.
 
Originally Posted by dogememe
I don't believe that 100k mile Iridium plugs would cause an extended crank time.

Me either. Though, I just replaced the fuel pump cartridge on a 05 Corolla to resolve an extended crank time problem. The extended crank time would only manifest when the engine was hot. The car could sit for weeks or days and start up perfectly.
 
Originally Posted by dogememe
I don't believe that 100k mile Iridium plugs would cause an extended crank time.


It depends on the state of the ground electrode, if the Laser Iridium's platinum disc on the ground electrode is worn off, then you are left with the regular material, that wears more quickly.
 
TT is the ultimate choice for performance and durability full stop. It cranks longer during hot typically is fuel pump dying symptom and not spark plug issue.
 
Originally Posted by dogememe
I don't believe that 100k mile Iridium plugs would cause an extended crank time.

My SUV has plugs with 300K on them and it starts right up.
 
Originally Posted by Warstud
Originally Posted by dogememe
I don't believe that 100k mile Iridium plugs would cause an extended crank time.

My SUV has plugs with 300K on them and it starts right up.

Exactly my point. The plugs in my Vic were extremely worn to the point of causing slight misfires but it cranked right up with no delay. I suspect the problem with the OP's Corolla is elsewhere.
 
Originally Posted by Char Baby
Platinum TT or Iridium TT?
I've never heard/seen Plat TT even at our local parts stores.

Iridium tt is the ultimate, forget about platinum tt
 
The Plat TT are a single Platinum plug good for around 60k. I have a set of them in my Dodge Truck and they work fine.

Only difference in single platinum, double platinum, and iridium is how long they last. None of them will differ in performance for a street car.
 
Originally Posted by kr_bitog
Originally Posted by Char Baby
Platinum TT or Iridium TT?
I've never heard/seen Plat TT even at our local parts stores.

Iridium tt is the ultimate, forget about platinum tt


I was just curious as I've never seen the Plat TT only the Irid TT. Yeah, IR is all I'd use in a modern engine.

Thanks
 
Originally Posted by The Critic
Originally Posted by dogememe
I don't believe that 100k mile Iridium plugs would cause an extended crank time.

Me either. Though, I just replaced the fuel pump cartridge on a 05 Corolla to resolve an extended crank time problem. The extended crank time would only manifest when the engine was hot. The car could sit for weeks or days and start up perfectly.


Had that fun problem on the 05 Matrix years ago. It was solved by the dealer reprogramming the computer and has been fine ever since. Luckily it was still under warranty.
 
Originally Posted by Jimzz
The Plat TT are a single Platinum plug good for around 60k. I have a set of them in my Dodge Truck and they work fine.

Only difference in single platinum, double platinum, and iridium is how long they last. None of them will differ in performance for a street car.


The TT means Twin-Tip. As explained in the first post, platinum on the center electrode and Titanium on the ground electrode.

[Linked Image]


Iridium alloy due to being more durable, allows Denso and NGK to reduce the diameter, for improved ignition characteristics.

my butto Dyno agrees, when I went to NGK Laser Platinum to NGK Iridium-IX, but at reduced life, due to the ground electrode
 
Last edited:
Originally Posted by Char Baby
Platinum TT or Iridium TT?
I've never heard/seen Plat TT even at our local parts stores.

Pepboys and Autozone to carry it here, I'm sure others too.
Originally Posted by dogememe

https://www.denso.com/global/en/pro...e-parts-and-accessories/plug/platinumtt/

Funny that the graph at the bottom of that link shows the 1ZZFE
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.

All the Iridium TT recommendations got me leaning towards it now. The Platinum TT has a 1.1mm electrode vs 0.4 mm for the Iridium TT.

Regarding the starting behaviour, I see fingers pointed at the starter, fuel pump and ECU; all are original. Like I mentioned in the first post, it is only about a second longer than it should be (doesn't that seem like an eternity when cranking :)).
Out of curiosity, why would a fuel pump act up only when the engine is hot?
 
All else being equal, iridium has a lower resistance than platinum. Like everyone else said, just get another set or iridium plugs.
 
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