Annoying Idle rpm stuttering *FIXED*
 

When the car comes to a stop light and i sit there (manual) the rpm sometimes dips below 500rpm and makes the car shake for a second. First I tried the mikachu grounding system. That god rid of the low idle fluxation on cold start, however it did not solve the problem when the car was warm.
Next up I tried iriduim denso plugs, that didn't solve the problem either. At my wits end I decided to try indexing my iriduim plugs. This worked! No more annoying low rpm feels like the cars gonna die stuttering! Sparkplug indexing is where you take the conducting strap and mark it with a marker on the porcelean part. Then you align the conducting strap facing the exhaust port, which results in fresh air/fuel hitting the sparkplug right away!
-Enjoy!

Good post idea! I've got those same plugs and like them.
Am surprised that you'd have this problem with two sets of very different plugs.

Where are the other people complaining though? I mean, it's a puzzle! You had a real problem and it was fixed by your method. But all our engines are about alike, and we don't stutter and don't have indexed plugs.

I draw no inferences but am really puzzled! Yes, indexing is a good thing just as a matter of course. Never heard of it fixing a miss at idle speed, but it makes sense in your example for sure.

thanks!

I have noticed the problem after the car was broken in.....i was thinking i had a set of fouled plugs or something.....It's shuttering at idle with common drops to 500 rpm's and a bit of shaking....I'll try the indexing thing and let you know ...Thanks for the info

oh yeah btw, i have a grounding system someplace i have posted all that....if you care to check it out.......It didn't help my shuttering problem either.

Any way you could post pics? I am having a hard time visualizing this.

Thanks

Re: Annoying Idle rpm stuttering *FIXED*
 

This is a new one to me! Can you post up some DIY style pics and help some of us out!? Can you index stock plugs?

Turn off the A/C.

g-g-g-g-glad you figured it out

I have that same issue- a bit annoying at times. Pics would be GREAT and yeah can you do it to stock plugs?

^^
what he said

Index the plugs? I'm sorry, but when I put a plug in, I torque it to the proper torque and leave it...I'm not going to loosen it or try to tighten it more just to get the plug to point to the exhaust port. This will either allow you to not have the plug tight enough or maybe strip it trying to turn it further. I say no way! Like the other guy said...turn off the A/C. It's just the compressor kicking on and off.

How about turning off scion life !!! Smart @$$ ............

I don't think he meant it as being a smartbutt... There is some logic to what he is saying.

Oh i get it..........Roast my @$$ off down here when i paid for a car with a/c that should work properly and not screw up my idle ........but hey it's only a $14 k Scion xB not a caddy ....Sorry bout that

Hey, don't get ____ed at me...I'm just stating my opinion. I'm not "roasting" you or anybody...I just don't think I want to possibly strip out a spark plug thread on my ALUMINUM head trying to get the plug to face a certain way. You can do whatever you want. I'm just saying I wouldn't do it. Have fun, and invest in some heli-coils while you're at it. I hope it works for you.

When indexing...if it's only an 1/8th of a turn from being lined up, you shouldn't have a problem tightening it up a little more...but 3/4 turn away? I wouldn't try it...and loosening it to match up could cause serious issues too.

indexing is something people have done for years.....cars typically run better once done

I don't see any logic behind how turning the plug so that the arch faces the exhaust valve would make any bit of difference.......


Not saying that it dosen't work (in some mysterious way), or dis-creaditing what you've posted

^^^ Because then the spark is exposed directly to the incoming fuel/air. Having the "arch" towards the incoming mixture puts the spark indirectly out of the way.

https://static.summitracing.com/glob.../mor-71910.jpg Spark Plug Seat Style: Flat
Spark Plug Thread Size: 14mm
Washers Included: Yes
Washer Material: Copper
Washer Sizes (in): 0.043/0.054/0.064
Quantity: Sold as a kit. Spark Plug Indexing Washers, Copper, Flat Seat, for 14mm Plugs, Sizes .043, .050, .064 in., Set of 30

this is how you do it :lalala:

Good find.

Here is a good write up on how to index spark plugs. http://www.fordmuscle.com/archives/2...gs/index.shtml
Our spark plugs sit much lower than those in the guide; therefore I have extended the line they used for marking up to the very top of the porcelain (white part). You will now be able to see the index mark as you look down your spark plug chamber. The use of spark plug washers are highly recommended to get proper indexing/torque spec.

Post up some results once you guys try this :) It was one of the most annoying things about the car as it would stutter/stumble below 500rpm without the AC being on. I've also noticed, that with the AC on it still stumbles once in a blue moon; with the AC off however it NEVER stumbles anymore.

Good article...one thing I noticed was the fact that you can try several plugs to get one that indexes the best for that particular hole. I like this idea more so than the indexing washers or spacers. The washers are a neat idea as well, but it seems like a lot more trouble getting the right washer by trial and error and also you are pushing the plug out of the combustion chamber with the thicker washer/spacer. I would maybe suggest buying 8 or 10 plugs and trying to get the ones that index or point to the exhaust port the best. You can always take the extra plugs back (unless you write on them...find a different way to mark them). That was a good article and what I read makes sense. Although I haven't noticed whether my xB drops RPM at idle, I may do this for performance and MPG. It can't hurt, anyway. Once again Grimgrak, good article...and thanks for the tip.

Excellet !! Now we all agree this could be a good thing if done properly...........Great article by the way !! i'm checking mine out today.

Accel makes a tool ust for this. Its a small hand held die thats marked off to show just what size washer to use without having to install it on the vehicle. I'll try to find a pic or take one of mine. Been using one for years to help on cars with multiple spark discharge systems.

http://www.cyclepages.com/ProductGro...roupID=4601935
Here you go

I don't quite get the need for a $16 dollar tool for the job! Usually just setting the electrode so that is not pointed towards the intake will give you some benefit.

This is a great thread! Another good "how to" is at http://www.advanceautoparts.com/engl...0001001sp.html

Some times you don't need the washers, and can move the plugs from cylinder to cylinder till you find the right indexing.

Does anyone have a picture of the underside of the head to show where the opening of the electrode should be ideally placed?

Do the washers need to be flat or tapered?

They are flat, but don't use just any steel washer you have laying around. Spend the money and get indexing washers. The copper material crushes to shape and allows for better indexing without exceeding the maximum torque and possibly stripping the threads on the head.

The benefits of Indexing are debatable. The engine design and operating conditions will dictate the end results. However, it can not hurt and almost impossible to do damage if done wrong (as long as you don’t over torque).

The way I do it is to make a mark on my spark plug socket and put the plug it the socket indexed to my mark. I can then see where the index mark is and get it to within about 1/8 of a turn of the perfect spot. As long as the back of the electrode is not toward the “open” part of the combustion chamber, it is of some benefit.

Yeah I wasnt gonna find any old washer. I noticed there are two styles of copper indexing washers, flat and tapered and I wanted to know which I would need.

:relief:

I was hoping someone would mention this.

Overtightening or loosening spark plugs is NEVER an option, no matter what the desired result.

I don't own an xB, but I remember seeing this being a TSB where they adjusted your throttle cable. Maybe someone can find the article...

I'm going to try this over the weekend, and I'll re-post. Mine also idles rather roughly at times....

anyone with a good deal on these plugs? link me baby!

I've just tried driving about 2000miles without using the copper washers to index the spark plugs. After i put in the washers and torqued them down i've been getting really crappy misires at idles. I suspect the washers have lifted the sparkplugs too high in the combustion chamber. The crappy idle problem has NOT been fixed. After switching to iriduim plugs it went away for about a week and has now come back. I've now tried adjusting the throttle cable and even had the car cold idling at 2000rpm and by the end of the day the ecu will bring it back down to 500-750rpm making it stumble and idle like garbage again. Car has less than 5000 miles on it and this problem is really bothering me. Does anyone know where the idle adjustment screw is? Possibly in the online tech manual? What section?

I would not go making anymore changes, I would take it to the dealership.

i may try this

Some of you guys are pretty dense. You don't force the plug to line up or loosen it if it just wont line up. You either try the plug in a different spot to see if it lines up better or you try another plug. You may go through a few plugs trying to match them up to your cylinder head.