Nissan 240SX Forums banner
Cancel
Create thread New Garage Forums

spark plugs again...

Jump to Latest
1 - 20 of 29 Posts

spartanmisfit

· Registered
Joined
·
1,156 Posts
Discussion starter · #1 ·
Well this all stems back about 2 months ago. My car was boggin really bad when in full boost. So I bought some new spark plugs bkr6e's or whatever and the car ran fine. Shortly afterwards I put in a manual boost controller because my avcr broke and turned the boost up to 13 lbs. Then I went out and bought some ngk bkr7i's or whatever and dedcided to put them in when I burned the 6's up. So it finally started boggin again this past week so I put in the iridiums today. Well when I took it out for a test drive it was horrible. Even worse than the first time. It runs fine when not under boost but when under full boost it's really bad. when I turn the boost down to around 7 lbs it's a little better but it still does it a little. any ideas?
 
#2 ·
yeah, take a shotgun, close your hood, step back about 6-7 feet, and just blow a hole in it... works like a charm...
 
Save
Reply Quote Like Like
#4 · (Edited)
i know who you need to see about this problem... i hear he can get parts overnighted from japan.....
Image


for real though, could it be your A/F ratio is out of whack?? running lean/rich under boost?... might help if we knew a little more about your set up... SR? KA-T? etc.....

EDIT sorry just now saw this was in SR forums... much bad..... still sounds like an A/F prob to me.... maybe a timing issue...detonation real bad...
 
Save
Reply Quote Like Like
#6 ·
if your fouling plugs, you wouldnt want to go to a colder plug like you did. I run ngk 7 temp range and they do decent. I run the cheap copper plugs though because they are less than 2$ apiece and I can afford to change them often if needed. Copper plugs dont last long but are just as good as high dollar plugs while they last. How often do you foul plugs? Im cool changing mine with my oil as cheap as I can and I never have a issue with them because of that. Turbo cars run rich and that kills plugs.

Here is how heat ranges work on plugs in a nut shell.
You want to run the coldest plug you can while having it still be able to clean itself. The ceremic in them gets hot and helps keep the plug cold. A warmer plug has more ceremic in it and while it helps burn off deposits on the plug it creates higher clyender temps and can lead to detenation. A colder plug helps cool the cylender temps cooler but fouls out easier if it cant keep itself clean.
Maybe you need a better tune, but what I would try is some bkr-e plugs. I would go with a 6 most likely if your in the 250-350 range and a 7 if your over that.

Another thing im wondering is what your gapping them at? You might need to keep everything I said above in the back of your mind, but now that I think about it what you have sounds like blow out. What that is is when the air actually blows the spark out. You want the largest spark plug gap you can have without having blowout. I have mine at 26. I didnt do anything scientific with that, just took it as a suggestion from people with similar setups and it worked, I have plenty of power so I just roll with it. If you want to know how to figure out what is your best gap here is how:
Set your gap lower than you know youll want it. Say 22 or so. Then run it. Then raise it by 1. run it, repeat. When you start getting blow out take it down 2 and leave it there. It should be relieble and you should get the most performance out of it. You do know that you need to check your gap occasionally too because it will grow. Bumping it down 2 from where you got blow out will bring you right back into blow out in the future if you dont keep tabs on it.
Figuring out the best heat range and gap would be best to do on cheap plugs mostly because of the price and the possibility of fouling them out or deciding that you dont want that heat range. After you figure all that out, then go ahead and spend too much money on plugs if you must. They arnt going to last no where near 100k miles, them might last 5 oil changes if your lucky and they are at least 5 times as expensive usually.

Hope I could help and didnt confuse you.
 
#7 ·
im goning with him ^^^ with the gap thing. most plugs are gapped to or around 0.040 and yes for our turbo cars you want a lot less. i have mine gapped around 0.028.

but if you are still having this problem i would check into your coil packs. i had one that was weak. the car ran fine at stock boost but if i turned the boost up it would misfire bad only when i was in the throttle pretty hard. but every time it did this it would put a small crack in the porceline. hairline it was almost impossible to see.

i would change all my plugs and make sure u lower the gap. if you still have the problem, change the plugs and find out which coil pack it is. plus the cylinder that was misfiring the plug was a lot more blacker from the fuel soot. hope this helps.
 
#8 ·
4x4le said:
if your fouling plugs, you wouldnt want to go to a colder plug like you did. I run ngk 7 temp range and they do decent. I run the cheap copper plugs though because they are less than 2$ apiece and I can afford to change them often if needed. Copper plugs dont last long but are just as good as high dollar plugs while they last. How often do you foul plugs? Im cool changing mine with my oil as cheap as I can and I never have a issue with them because of that. Turbo cars run rich and that kills plugs.

Here is how heat ranges work on plugs in a nut shell.
You want to run the coldest plug you can while having it still be able to clean itself. The ceremic in them gets hot and helps keep the plug cold. A warmer plug has more ceremic in it and while it helps burn off deposits on the plug it creates higher clyender temps and can lead to detenation. A colder plug helps cool the cylender temps cooler but fouls out easier if it cant keep itself clean.
Maybe you need a better tune, but what I would try is some bkr-e plugs. I would go with a 6 most likely if your in the 250-350 range and a 7 if your over that.

Another thing im wondering is what your gapping them at? You might need to keep everything I said above in the back of your mind, but now that I think about it what you have sounds like blow out. What that is is when the air actually blows the spark out. You want the largest spark plug gap you can have without having blowout. I have mine at 26. I didnt do anything scientific with that, just took it as a suggestion from people with similar setups and it worked, I have plenty of power so I just roll with it. If you want to know how to figure out what is your best gap here is how:
Set your gap lower than you know youll want it. Say 22 or so. Then run it. Then raise it by 1. run it, repeat. When you start getting blow out take it down 2 and leave it there. It should be relieble and you should get the most performance out of it. You do know that you need to check your gap occasionally too because it will grow. Bumping it down 2 from where you got blow out will bring you right back into blow out in the future if you dont keep tabs on it.
Figuring out the best heat range and gap would be best to do on cheap plugs mostly because of the price and the possibility of fouling them out or deciding that you dont want that heat range. After you figure all that out, then go ahead and spend too much money on plugs if you must. They arnt going to last no where near 100k miles, them might last 5 oil changes if your lucky and they are at least 5 times as expensive usually.

Hope I could help and didnt confuse you.
Click to expand...
Having trouble spelling cylinder? lol jk man
How do you gap the spark plugs, i never put thought into it, and how do you check gap, there might be a thread on here, but i'm too lazy to search and maybe the OP is about to ask that, plus you took the time to explain that so i figure you won't mind ;)
 
#10 ·
willdrift4food said:
Having trouble spelling cylinder? lol jk man
How do you gap the spark plugs, i never put thought into it, and how do you check gap, there might be a thread on here, but i'm too lazy to search and maybe the OP is about to ask that, plus you took the time to explain that so i figure you won't mind ;)
Click to expand...
dude, you dont check the gap on your plugs? I ALWAYS have the gapps wrong even on pre gapped plugs. Never trust the gap that comes on a plug.


Hey, you need to join tennspeed.net man! You need to come to deals gap with us and run the dragon!
 
Discussion starter · #11 ·
Yeah it could be the gap, but my problem with that is my spark plugs are turning dark red immediately now. Plus when it was working I didn't gap them and it ran perfect for about 2 and a half months before they fouled out now it's fouling out as soon as I hit full boost. I've tried 4 types of spark plugs in the last week, but I also havnt gapped any mostly becuase someone said it doesnt need to be gapped.
 
#14 ·
4x4le said:
dude, you dont check the gap on your plugs? I ALWAYS have the gapps wrong even on pre gapped plugs. Never trust the gap that comes on a plug.


Hey, you need to join tennspeed.net man! You need to come to deals gap with us and run the dragon!
Click to expand...
Me? Or the OP?
Either way, i'm gonna join tennspeed.net considering i'm like 15 mins from the border..
 
#15 ·
4x4le said:
they said they didnt need gapped? Ive never got 4 plugs with the exact same gap (maybe im unlucky) but the thing is the plugs are for a sr20de non turbo, not turbo. The gap is big.
if your fiouling them that fast too you probably need a tune.

Ill be honest, Ive never seen plugs turn red
Click to expand...
You generally dont gap iridium plugs
 
Discussion starter · #16 ·
well im on my way to buy some bkr6e's and 7e's and gap em and see how they run. Oh and red pluigs means im running lean usually, but I don't know why I'd be running lean because my a/f meter shows stoich or rich, so I'm pretty confused.
 
Discussion starter · #19 ·
Well I had a boost leak unfortunately. I had a hole in my intercooler piping right where it goes under the battery brace or whatever it's called. So I made a quick fix and it's sealed now, but I'm still bogging out a little. Not as much but still I am. Mostly in 3rd 4th and 5th gears. Hardly any in 1st and 2nd. It could be because the plugs are already fouled. I dunno but I'm gonna change the plugs again and find out.
 
1 - 20 of 29 Posts
About this Discussion
28 Replies
8 Participants
Last post:
spartanmisfit
Nissan 240SX Forums
posts
1.6M
members
94K
Since
2002
A forum community dedicated to Nissan 240SX owners and enthusiasts. Come join the discussion about performance, builds, engine swaps, turbos, modifications, classifieds, troubleshooting, maintenance, and more!
Full Forum Listing
Explore Our Forums
S13 240SX (89-94) New Member Introductions General Tech S14 240SX (95-98) KA24DE & KA24E