Spark Plug Install Instructions

Went down to the subaru dealership and picked up 4 SILFR6A's. They were pregapped to .029, so i opened them to .030 since i'm just running a stock LGT. Get a little bigger spark without risking misfire. One hour and 20 minutes had them installed w00t. next up is tranny and diff fluids

 

-Luke

Got the plugs done today, took about three hours, going slowly, taking time to clean everything and painting the battery harness and tie downs. Here is a pic of the plugs. I wish I knew which one cylinder two was, I had a PO203 misfire code and am hoping this corrects it, but they all look pretty much the same. The CEL would come and go for the last 5-7k or so.

Got the plugs done today, took about three hours, going slowly, taking time to clean everything and painting the battery harness and tie downs. Here is a pic of the plugs. I wish I knew which one cylinder two was, I had a PO203 misfire code and am hoping this corrects it, but they all look pretty much the same. The CEL would come and go for the last 5-7k or so.

 

is the gap on all of them exactly the same? somtimes if the tip errodes over time it widens the gap causing misfires.

 

-Luke

Pretty damn close, they were all less than .032 we'll see if the CEL comes back I guess.

I wish I knew which one cylinder two was, I had a PO203 misfire code and am hoping this corrects it

 

cylinder 2 is front right when standing in front of the engine.

Drivers side, I meant the plug though, didn't keep them in order when I took them out like I should have, but they all look basically the same.

I just did mine two days ago using the info from this site. Thanks, but really it wasn't nearly as bad as the OP made it sound. I must have a different car (2000 Legacy GT sedan). There were no coil packs, and the battery did not have to come out. I did remove the airbox tube near the bumper but even that was simple.

 

On the drivers side, I had to cut away part of the plastic washer bottle mount b/c of a rusted bolt that would not budge. I disconnected the electric motor and swung the bottle out of the way (didn't even have to empty it) and removed & replace the rear drivers side plug, then put the washer bottle back using one bolt instead of two. All told it was about an hour and a half job to do all plugs.

 

I put in Bosch Platinum Fusions and the difference was noticeable with the first start, but that might be just b/c the old plugs were so shot. Next time I would probably go with Bosh wires though, since the ordinary ones from Autozone had one wire that was just a tad too short (by about half an inch). It worked but I had to skip routing it through the plastic loom. I'd like to think the Bosch is better quality control for the price, but just guessing.

Edited September 1, 2009 by GRN00GT

Ok, so I went 8 days and the dreaded PO302 came back, WTF! So now what, coil pack, wiring, fuel injector, why would it be so random and come and go at will?

What about fuel injector?

Bad one?

does the JDM legacy gt take the same spark plugs? LFR7AIX?

So, my car was at the dealer today, I disconnected my access port but left the green connectors in the fuse box collected, but not under the pas side carpet. First thing they noticed. Asked me about aftermarket computer blah blah, I denied it. so they disconnected them and the CEL came back on, PO203 cyl 2 misfire. They found it had a bad coil, and that plug was loose, he said the washer wasn't even crushed. Also found my colder plugs but the tech said they were hotter? I just want to make sure I got the right ones now, LFR7AIX one step colder correct? So they wanted to put in the stock ones, $250 I said no I'll do it myself. Hopefully thats it now. Coil was covered by my extended warranty, but he said if I have problems in the future with the wrong plugs they may deny me, whatever.

Also found my colder plugs but the tech said they were hotter? I just want to make sure I got the right ones now, LFR7AIX one step colder correct?

 

Yes, LFR7AIX is colder.

 

I think the confusion is this: stock plugs are a "6" heat level, this is a 7. For NGK, the higher the number, the colder the plug.

 

For some other companies, the higher the number, the hotter the plug. So, maybe the mechanic/service advisor just wasn't up on NGK's way of doing things. Apparently it's totally arbitrary by manufacturer as to higher being hotter or colder (see http://www.sparkplugs.com), so it's probably an honest mistake.

So, my car was at the dealer today, I disconnected my access port but left the green connectors in the fuse box collected, but not under the pas side carpet. First thing they noticed. Asked me about aftermarket computer blah blah, I denied it. so they disconnected them and the CEL came back on, PO203 cyl 2 misfire. They found it had a bad coil, and that plug was loose, he said the washer wasn't even crushed. Also found my colder plugs but the tech said they were hotter? I just want to make sure I got the right ones now, LFR7AIX one step colder correct? So they wanted to put in the stock ones, $250 I said no I'll do it myself. Hopefully thats it now. Coil was covered by my extended warranty, but he said if I have problems in the future with the wrong plugs they may deny me, whatever.

 

Just keep some stock plugs around and swap them in before going to the dealer again...

Ya it's only a three hour job.

So the saga continues, picked up my car yesterday, drove about thirty miles, got a sticker, all's good. So I head to work today, CEL back on WTF!!! I get to work, with no problems. After I get out I check the code with the AP, 7 CODES!!! PO137 PFFFE PO302 P1152 P1153 PO852 P1518. So I cleared them and installed the AP then drove about forty miles, no more codes. I am going to assume the codes were from the colder plugs?? Stock engine doesn't like em?? Who the **** knows. Edited September 30, 2009 by SuperhawkLGT

Another day another CEL, PO203 back and PFFFE, what the hell is that one?

Here's what I got:

Thank you for your order at Sparkplugs.com. Below is a summary of your order for your records:

4 - NGK IX iridium

Stock Number: 2309

Part Number: LFR7AIX

 

Seemed to be just like the originals, and worked fine.. (for 20+K so far)

 

Interestingly enough, according to sparkplugs.com, there are different brands of plugs, with DIFFERENT OE gaps for our car..

http://www.sparkplugs.com/results_app.asp?productTypeID=1&AAIA=1430733

 

Autolites are pre-gapped to 0.040, Denso to 0.035 and Champion and NGK to 0.030.

 

Does this mean they're all equivalent (i.e. Autolite plugs are slightly different and will work in the LGT at 0.040)?

 

On the other hand:

http://www.sparkplugs.com/results_cross.asp?pid=lfr7aix&x=0&y=0

Shows that lfr7aix are pre-gapped to 0.032.

 

The SILFR6A are listed as "extreme long life", while the LFR7AIX are not. Given that I'm changing 'em every 30-40K anyway, does it matter? The LFR7AIX are one step colder (I'm stage 2), and 2/3 the price of the SILFR6A. They don't list an SILFR7A...

 

Wow - "traditional" champion plugs are less than $3 each, $2.89, SILFR6A are $12 each. Not that I'd get anything but NGKs...

 

as the saying goes Chapion plugs are for mustangs, NGK's are for performance cars like ours. NGK all the way. I am ordering NGK LFR-7AIX today.

I never heard that saying.....

I have an almost brand new set of NGK LFR-7AIX if anyone is interested, well less than 1000mi on them.

So, installed another set of new plugs, stock ones this time, got it down to two hours. Idle seems a bit smoother right now, time will tell if that was the problem, I am doubting it, still think it's an injector.

Did my first set of spark plugs ever today. I was anxious to do it previously, but reading this thread really helped.

 

Helpful cliff notes for me:

Little space to work, so make it easier.

Have the tools; 5/8 plug socket, 3" and 4" extension, U-joint, offset wrench, anti sieze lube,... Its a small cost for the saving of time, frustration and/or additional money.

180* rotating of the rear coil packs for removal/install really helped.

Remove battery and airbox, its not difficult and saves time/knuckles.

Otherwise the directions are simple, just take your time.

 

The plugs I removed today looked very good for 35k miles of use (93k miles currently), running a little rich maybe. Next, I'd like to get off cobb's ots maps and/or start logging asap. I had a slight stumble at idle, not sure if its totally gone yet, we'll see.

 

Thanks for the thread.

Thanks for the write up, BoxerGT! (though it was a few years ago)

 

I just finished replacing the plugs on my 05 OBXT, along with cleaning the MAF, correctly fastening down the battery and for curiousity's sake removing the intake resonator

 

Including two trips to autozone it took a little over two hours. I've pretty much done it all between wasting tons of money on my last daily driver, building a project car and being a mechanic for the better part of a decade for amature SCCA cars but had never touched a Subaru before other than changing its oil (I got it in the spring). So I'm glad this guide was here because I was pretty sure those were coil packs

 

The plugs were a pretty easy job but it would have made me mad if I didn't have an assortment of 3/8" extensions, though the three incher worked for most of it. I didn't end up needing to use a u-joint I was able to use a 12mm wrench

 

My advice from today is to skip the autolite iridiums. They don't come pregapped like they are supposedly. On one of the plugs out of the box the hanging electrode was drooping and pressing against the iridium center!! On another the gap must have been twice spec, which the others were (~0.040"). I wonder if they came that way from autolite or if it was from transport.

 

NGK's are pretty and run great. The OBXT has 51,400 and it was running notably smoother after the whole thing - though admittedly it was one of the coldest times I've driven it so it may have been the cold intake air that hit the rev limiter

So, installed another set of new plugs, stock ones this time, got it down to two hours. Idle seems a bit smoother right now, time will tell if that was the problem, I am doubting it, still think it's an injector.

 

New plugs helped smooth drivability out, but still have a slightly lumpy idle. Pretty sure its an injector issue w/ me too.

My check engine light is gone right now, I had an appt at the stealership but the light went out. I hope it stays out, but I doubt it.