i will never change plugs again.. stumped.. - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

two40guy · 04-12-2012, 08:02 PM

alright.. so i had a problem a while ago where i would WOT and my car would rip through boost but then start to backfire and power would drop off.. i boost leak tested it and it went away and ripped would still hiccup at very high rpm near redline but thats it, and every so often very randomly at idle it would spit once or twice and that would be it, well tomorrow is my first track day so i figured what the hell ill change plugs it might fix the spitting problem and theyve gone through a ton of crazy boost leaks so it was probably just time to change them, i changed them and thats when my car started running terrible, i changed them and it idled smooth so i was pumped but then revved it and instantly when you rev it it drops to 5 cylinders goes back to idle and idles on 5.. here's what ive done/found out thus far,

coils and plugs all spark

spark plugs are black around the the bottom of the threads
but are white and dusty on the tips. all 6. (indicating lean?)

Tested TPS and at closed throttle had a reading of .59v and open
.79v. way wrong.. tried adjusting it but it wouldnt really change
and when ever the key is on its at a constant 9.5

i checked for boost leaks - None

all coil harness grounds and stuff are connected..

Im confused litterally all i did was change plugs.. i got the same exact plugs and everything.. gapped the same. im getting frustrated and not thinking of things, any suggestions would be greatly appreciated. TPS is making me very iffy though.. putting my money on that.. sorry for the rant.

ultimateirving · 04-12-2012, 08:12 PM

whoaaaa, start with the TPS, get the voltage set right and make sure its not messed up. Also what gap was the old plugs, what gap is the new plugs. What heat range?
how much boostyou running?

two40guy · 04-12-2012, 08:18 PM

i move the tps and it doesnt really change.. to clarify im testing it with a multimeter set to 20v and i tested both wires to see.. and nothing you turn it and it basically does nothing.. im thinking its that.

plugs are ngk's heat range of 6 gapped to about .03 might tighten it to about .020 and see if it helps but the thottle position sensor is freaking me out, thatd explain the lean fuckin car thinks im pussy throttling it everywhere haha but yeah 6's stock 10 lbs

ultimateirving · 04-12-2012, 08:45 PM

if ur tps isnt changing the voltage then that is a huge problem, and ur car wont drive at all.. also try gapping to .026-.028 for stock plugs and 10psi

two40guy · 04-12-2012, 08:47 PM

when i got it will run at idle because i mean its off but not HORRIBLE but the second you rev it hard it breaks up but i notices if you slowly press the gas.. and i mean slow, itll rev kinda smooth until a certain point. gay.. looks like im missing track day

*fliprayzin240sx* · 04-12-2012, 11:00 PM

You might wanna take that picture off...some folks are checking these forums out at work.

Psychomoongoose · 04-13-2012, 11:53 AM

Quote:

Originally Posted by fliprayzin240sx

You might wanna take that picture off...some folks are checking these forums out at work.

This, i just went exorcist trying to see if there was any objectionable person's eyeballs within looking distance of my screen.

Te37 · 04-13-2012, 11:42 AM

Process of diagnostics: Put old plugs in and see if problem persists. If it does you have had a heart attack when you went in for a broken leg. If the problem goes away then your plugs are wrong, or gapped differently. Take the plug from the cylinder that goes out and put in another cylinder...etc

KendallH · 04-13-2012, 11:57 AM

Switch up to heat range 7s

titangts · 04-13-2012, 09:43 PM

Check for loose wires at the coil pack..ive had that issue on my SR and my older vq35 s13. both had one coil that had one wire loose..wiggling it would cause it to run on that cylinder or not.

also .20 gap is WAY to low in my opinion. that was probably causing you to miss up high RPMs.. you were experiencing ignition blow out. since the gap is so small, the spark is literally blow out in high RPM.

my 400whp Rb25 car used NGK BKR7e gapped at .28. never missed a lick.

Walperstyle · 04-13-2012, 09:53 PM

Change the picture? ...maybe people should change the line of work they are in.

two40guy · 04-14-2012, 05:11 PM

titangts- i have them gapped at .25, i went somewhere in the middle of what i had, and it made a huge difference at first, but then on my way to my friends house before i was going to go to the track it started running shitty again.. but i think i may have some sort of break through. i noticed the coil harness ground that goes at the back by coil #6 was kinda loose in its ring terminal so i crimped it tighter and it mad a HUGE difference i can WOT now and stay on 6 cylinders and it will rev out until higher rpm about 5k ish. so im thinking some loose ground wires on some coils. or something

ps. picture has been taken down.. tell your friends and shoot your thoughts on to my thread in the form of ideas! thanks guys!

04-12-2012, 08:02 PM	#1
two40guy Zilvia Junkie Join Date: Sep 2009 Location: binghamton,ny Posts: 442 Trader Rating: (9) Feedback Score: 9 reviews	i will never change plugs again.. stumped.. alright.. so i had a problem a while ago where i would WOT and my car would rip through boost but then start to backfire and power would drop off.. i boost leak tested it and it went away and ripped would still hiccup at very high rpm near redline but thats it, and every so often very randomly at idle it would spit once or twice and that would be it, well tomorrow is my first track day so i figured what the hell ill change plugs it might fix the spitting problem and theyve gone through a ton of crazy boost leaks so it was probably just time to change them, i changed them and thats when my car started running terrible, i changed them and it idled smooth so i was pumped but then revved it and instantly when you rev it it drops to 5 cylinders goes back to idle and idles on 5.. here's what ive done/found out thus far, coils and plugs all spark spark plugs are black around the the bottom of the threads but are white and dusty on the tips. all 6. (indicating lean?) Tested TPS and at closed throttle had a reading of .59v and open .79v. way wrong.. tried adjusting it but it wouldnt really change and when ever the key is on its at a constant 9.5 i checked for boost leaks - None all coil harness grounds and stuff are connected.. Im confused litterally all i did was change plugs.. i got the same exact plugs and everything.. gapped the same. im getting frustrated and not thinking of things, any suggestions would be greatly appreciated. TPS is making me very iffy though.. putting my money on that.. sorry for the rant. Last edited by two40guy; 04-14-2012 at 05:12 PM..

04-12-2012, 08:12 PM	#2
ultimateirving Zilvia FREAK! Join Date: Nov 2010 Location: arizona Age: 37 Posts: 1,521 Trader Rating: (1) Feedback Score: 1 reviews	whoaaaa, start with the TPS, get the voltage set right and make sure its not messed up. Also what gap was the old plugs, what gap is the new plugs. What heat range? how much boostyou running? __________________ Z32 with lq4 swap Desert Street Scene \|\| Dssevents.com

04-12-2012, 08:45 PM	#4
ultimateirving Zilvia FREAK! Join Date: Nov 2010 Location: arizona Age: 37 Posts: 1,521 Trader Rating: (1) Feedback Score: 1 reviews	if ur tps isnt changing the voltage then that is a huge problem, and ur car wont drive at all.. also try gapping to .026-.028 for stock plugs and 10psi __________________ Z32 with lq4 swap Desert Street Scene \|\| Dssevents.com

04-13-2012, 09:53 PM	#11
Walperstyle Nissanaholic! Join Date: Nov 2004 Location: Alberta, Red Derp Age: 44 Posts: 1,729 Trader Rating: (0) Feedback Score: 0 reviews	Change the picture? ...maybe people should change the line of work they are in. __________________ KA-T ORG-Function over Flush

04-12-2012, 08:18 PM	#3
two40guy Zilvia Junkie Join Date: Sep 2009 Location: binghamton,ny Posts: 442 Trader Rating: (9) Feedback Score: 9 reviews	i move the tps and it doesnt really change.. to clarify im testing it with a multimeter set to 20v and i tested both wires to see.. and nothing you turn it and it basically does nothing.. im thinking its that. plugs are ngk's heat range of 6 gapped to about .03 might tighten it to about .020 and see if it helps but the thottle position sensor is freaking me out, thatd explain the lean fuckin car thinks im pussy throttling it everywhere haha but yeah 6's stock 10 lbs

04-12-2012, 08:47 PM	#5
two40guy Zilvia Junkie Join Date: Sep 2009 Location: binghamton,ny Posts: 442 Trader Rating: (9) Feedback Score: 9 reviews	when i got it will run at idle because i mean its off but not HORRIBLE but the second you rev it hard it breaks up but i notices if you slowly press the gas.. and i mean slow, itll rev kinda smooth until a certain point. gay.. looks like im missing track day

04-12-2012, 11:00 PM	#6
fliprayzin240sx Man w/ CTSV & a Car Seat Join Date: Aug 2002 Location: Tampa Posts: 17,998 Trader Rating: (19) Rides Gallery: fliprayzin240sx Feedback Score: 19 reviews	You might wanna take that picture off...some folks are checking these forums out at work. __________________ If you think Zilvia has too many assholes... CLICK HERE!!!

04-13-2012, 11:42 AM	#8
Te37 Zilvia Addict Join Date: Jan 2012 Location: Atlanta Age: 32 Posts: 618 Trader Rating: (1) Feedback Score: 1 reviews	Process of diagnostics: Put old plugs in and see if problem persists. If it does you have had a heart attack when you went in for a broken leg. If the problem goes away then your plugs are wrong, or gapped differently. Take the plug from the cylinder that goes out and put in another cylinder...etc

04-13-2012, 11:57 AM	#9
KendallH Zilvia Addict Join Date: Jan 2011 Location: Clearwater, FL Level: Master Troll Age: 33 Posts: 871 Trader Rating: (3) Feedback Score: 3 reviews	Switch up to heat range 7s

04-13-2012, 09:43 PM	#10
titangts Zilvia Addict Join Date: Jul 2009 Location: charlotte Posts: 666 Trader Rating: (10) Feedback Score: 10 reviews	Check for loose wires at the coil pack..ive had that issue on my SR and my older vq35 s13. both had one coil that had one wire loose..wiggling it would cause it to run on that cylinder or not. also .20 gap is WAY to low in my opinion. that was probably causing you to miss up high RPMs.. you were experiencing ignition blow out. since the gap is so small, the spark is literally blow out in high RPM. my 400whp Rb25 car used NGK BKR7e gapped at .28. never missed a lick.

04-14-2012, 05:11 PM	#12
two40guy Zilvia Junkie Join Date: Sep 2009 Location: binghamton,ny Posts: 442 Trader Rating: (9) Feedback Score: 9 reviews	titangts- i have them gapped at .25, i went somewhere in the middle of what i had, and it made a huge difference at first, but then on my way to my friends house before i was going to go to the track it started running shitty again.. but i think i may have some sort of break through. i noticed the coil harness ground that goes at the back by coil #6 was kinda loose in its ring terminal so i crimped it tighter and it mad a HUGE difference i can WOT now and stay on 6 cylinders and it will rev out until higher rpm about 5k ish. so im thinking some loose ground wires on some coils. or something ps. picture has been taken down.. tell your friends and shoot your thoughts on to my thread in the form of ideas! thanks guys!