dmarciano

I'm going to be replacing my spark plugs soon on my 07 tC. I'm trying to find out what the range is for the gap setting. I've seen a few people mention .035". I'm assuming that's the middle of the range. I was curious though if this is correct and what the min - max was for the gap. Thanks.

mattieg

why are you replacing the spark plugs allready? They are good for 100,000 miles. Are you using nitrous or going F/I?

ack154

iTrader: (7)

a) read what that guy wrote.

b) the gap setting should be in your owner's manual

dmarciano

a) I'm coming up on about 85K. I know the car is only two years old but I do a lot of driving for work. I'm not replacing them today or anything, but I'll probably be around the 100K mark in less than a year.
b) I've been trying to find the owner's manual online but I've had no luck and mine got stolen.

ack154

iTrader: (7)

I don't believe there's a copy online. I can go get mine and check though... brb...

ack154

iTrader: (7)

So my 2005 manual says:

gap: 1.1 mm or .043"

Plugs should only be Denso SK20R11 or NGK IFR6A11, iridium only.

And actually it also says you shouldn't adjust the gap. So if you order from Toyota, they should come with the proper gap already set. And really, those would be the best plugs you could get.

dmarciano

Thanks!

SFTifoso

If you get Denso or NGK Iridium plugs, you don't need to adjust anything. The iridium tip is actually quite easy to break. The OEM spec plugs from those two companies are the "Long Life" Iridium plugs. The other variety of iridium plugs have a smaller tip, and will perform better, but won't last as long.

sciontc_mich

^^ but it doesn't hurt to look at the side electrode and make sure all plugs you get are gapped correctly. I have used a ruler (didn't have the feeler gauge) and even a feeler gauge to see if the gap was correct, ya never know from the factory!

ack154

iTrader: (7)

I'd agree with both of you... you shouldn't need to adjust the gap, but there's no harm in doublechecking as long as you realize they're fragile and need to be careful.

10gxiong

on my car, there was a sticker label on the valve cover that said not to switch the gap on the ngk iridium replacements. just leave em' as is from the box and install them.

alltracman78

The gap isn't supposed to be adjusted, but can be.
Just be careful of the tip, it's fragile.
Even if you want to go by the book and say you can't adjust, that's not the same thing as checking the gap. ;)

It's smart to check the gap of new plugs, just in case someone dropped one or it was misadjusted from the factory. Unlikely, but it does happen.

WAlterEgo

iTrader: (1)

they typically come pre-grapped alrdy , but always check to make sure. like said before, 1.0mm to 1.1mm (0.039 to 0.043 in.) for new spark plugs. got this from my repair manual at work

Skyone

I just changed my spark plugs....didn't bother adjusting or checking gap because it says to not adjust....but my engine seems to not be firing cleanly as the engine shakes more than it was before.... any ideas?

I'll probably go buy a gap checker and measure it to be safe.

sciontc_mich

the gap checker if it's not a feeler gauge (think straight metal strip) then don't use the round gap checker. Not good for iridium tipped plugs as we have!

How to measure then if you don't have a feeler gauge? Simple! Use a small ruler that is in mm, and just measure the distance (gap) between the side and center electrode. 1.1mm is the measurement.

Did you get the denso brand plugs? If so, return them and get the NGK Laser Iridium part 4589. also known as part IFR6T11.

I say this becuase I helped a friend (who has a tC) replace the plugs, we used denso, and after that the tc's engine shook and idle wasn't smooth, engine became very noisy. Replaced with NGK plugs mentioned above and the engine was nice and quiet ever since. That might be the issue for you.

Another thing to check is the plug's side electrode, make sure it's centered in the middle of the middle electrode. I've seen plugs with the side electrode bent and it doesn't line up (most likely was dropped).

hope that helps!

Skyone

Well, to update...I bought some NGK spark plugs....adjusted them to about 0.042" and installed them. The engine shakes even more than when I hadn't adjusted the spark plugs. I have an 06' scion tc.....and the manual doesn't mention anything for the spark plug gaps...just that you should get iridium tips and not adjust the gaps.

I will look into getting some Denso spark plugs straight from Toyota auto parts and if that doesn't work I'll go get those NGK lasers....(geez, it's gettin pretty pricey now for just changing spark plugs!)

sciontc_mich

the spark plug gap is in the owners manual under specifications, it's also on a sticker under the hood. emissions sticker. also anything from 1.0 to 1.1mm is fine for the adjustment.

yeah the NGK lasers is what I got for a friend of mine, worked fine. Others have uses the NGK Iridiun IX and was also fine.

Have you checked your maf sensor? Wondering if that's dirty, that can cause a rough idle.

Why did you replace the plugs in the beginning? was the idle rough then?

Skyone

I didn't have an idle engine before...but it's at about 100k miles so I figured I replace them now would be better than later. Yeah, it's shaking when idle like at a stop light. I should check the sensor....not sure how to...but I guess I'll search for it...google and on this forum.

Heading to toyota now for those original denso spark plugs...hopefully that'll do the trick.

BlackKnight

Thats what they want you to think every set of plugs I have bought for my tC have not been gapped to OEM specs they were at .044 or higher. Iridium are very fragile just be very careful and you will be fine gapping them. They only tell you not to so they will not be liable for engine damage if you mess up the tip of the plug and use it.

sciontc_mich

the sensor is on the air cleaner box. two screws hold it on, and has an electrical connector on it. CRC Industries makes a MAF Sensor cleaner, it's an electrical cleaner that is for MAF sensors. about $5 at the auto parts store. I think autozone has it too. just spray it down, let it dry and put it back in, screw down, connector back on. That's it.

I had a really bad idle and poor mpg's so I cleaned mine and it was much smoother. So I do it every 13-15k miles. That might be the problem too. Going through all those plugs and same issue, is starting to make me think something else. But 100k yeah time to replace the plugs.