Spark Plugs,can They Affect Idle?

[aleisha]

hi,i recently bought cheap spark plugs to go into my r33 but a couple hours after i put them in my car it started over revving????????

it usually revs at idle around 850 rpm but it now revs at 1200 rpm at idle.

could it be the cheap spark plugs cause i was told that cheapo ones arent good for turbo cars and i was meant to put either platinum or iridium dont know if thats the right spelling but yeah either of those 2.

any ideas?

[aleisha]

also when i was putting them in my friend increased the gap on all the spark plugs,he told me it helps with something like performance or making the spark plugs last longer?

just thought i would add that as well just in case when he made the gaps bigger it may have caused the problem because the idle was at 1400 rpm and i had to turn in the idle screw to get it down to 1200 rpm.

[Dorigecko]

plugs are plugs. so longs as they're in the right heat range they're fine. what part number are the plugs? should be a heat range of 5 or 6.

some people will tell you that you HAVE to buy platinums, other people will tell you that they do nothing. doesn't really matter...

the increase in gap would normally make it miss as the standard coil packs don't put out enough juice to spark anything past 1mm. most people do .9mm (standard gap). RB20s have 1.05mm gaps, so if you've got 1.1 it shouldn't be TOO bad.

Shouldn't really touch the idle screw man..

What else has been touched?

[aleisha]

  Dorigecko said:

plugs are plugs. so longs as they're in the right heat range they're fine. what part number are the plugs? should be a heat range of 5 or 6.

some people will tell you that you HAVE to buy platinums, other people will tell you that they do nothing. doesn't really matter...

the increase in gap would normally make it miss as the standard coil packs don't put out enough juice to spark anything past 1mm. most people do .9mm (standard gap). RB20s have 1.05mm gaps, so if you've got 1.1 it shouldn't be TOO bad.

Shouldn't really touch the idle screw man..

What else has been touched?

what happens when you touch the idle screw?i had no other choice as the car was revving too loud.

when i started it up it was like someone had there foot on the pedal contantly and there was no way i could drive my car around revving so high.

i will get the part number for the spark plugs in the morning as im taking them out,the only other things that have been touched are the plenum,the throttle body, the rocker covers and the aac valve,the plenum and throttle body had some carbon build up so we cleaned it all off and the same with the aac valve and we only took the rocker covers off because it made it a heap easier the put the plenum back on and we put it all back together carefully to make sure it was done right.as far as i know there isnt an air leak but they are near impossible to track down if there was one.

[blind_elk]

Oh dear, you cleaned carbon from the throttle body. This is a common cause for high idle in GT-Rs, so I wouldn't be surprised if the same thing happened in GTSTs.

You may also have dislodged the TPS so it no longer sends the "throttle closed" signal to the ECU.

[aleisha]

  blind_elk said:

Oh dear, you cleaned carbon from the throttle body. This is a common cause for high idle in GT-Rs, so I wouldn't be surprised if the same thing happened in GTSTs.

You may also have dislodged the TPS so it no longer sends the "throttle closed" signal to the ECU.

is there a way to fix this?i didnt know that cleaning carbon could do that to it and what is TPS?sorry not good with abbreviations and can that also be fixed?

[blitz r33]

  aleisha said:

what happens when you touch the idle screw?i had no other choice as the car was revving too loud.

when i started it up it was like someone had there foot on the pedal contantly and there was no way i could drive my car around revving so high.

i will get the part number for the spark plugs in the morning as im taking them out,the only other things that have been touched are the plenum,the throttle body, the rocker covers and the aac valve,the plenum and throttle body had some carbon build up so we cleaned it all off and the same with the aac valve and we only took the rocker covers off because it made it a heap easier the put the plenum back on and we put it all back together carefully to make sure it was done right.as far as i know there isnt an air leak but they are near impossible to track down if there was one.

we're in the same boat,it aint your spark plugs because mine was fine until i cleaned all the carbon from the throttle body and the top of the plenum as well.

now my car sits at high idle with no explanation of why it does it?

[mad082]

how did you clean the carbon off?

[BezerkR32]

vacuum leak will cause high idle, did you leave a hose off? should have also gapped the plugs down , not up. .8mm is good.

[joeyjoejoejuniorshabadoo]

bcpr7es @ .8

[StealthX]

you need to reset your ECU, or perform and Idle air re-learn.

cos the ECU has 'forgotten' the signal that determines how much air and how much the throttle needs to open, for a solid idle.

Problem is, ive got no idea how to do that on a skyline...

should be just pull out the fuse for the engine computer, then leave it for about 10 minutes, then pop the fuse(s) back in and that should do it.

But then again, ive never done it on a skyline.

Take it to a nissan dealer, they can do it all for cheap as chips, or someone in here will know how to do it...

try this thread for more info: http://www.skylinesaustralia.com/forums/Hi...Rb-t297518.html

and these two DIYs should solve your problem (i hope!)

http://www.skylinesaustralia.com/forums/Di...tml&hl=idle

http://www.skylinesaustralia.com/forums/Ni...tml&hl=idle