Misfire - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Art · 02-13-2002, 02:31 PM

hey guys, I'm having this problem with a misfire.  I had the timing checked by a mechanic and replaced the whole exhaust system and a new cat.  I replaced the spark plugs with platinum ones and put on magnecore wires.  After putting on my intake, the problem seemed to get worse, or louder.  Could it be my injectors (I've gone through a couple of bottles of fuel injector cleaner). I really need to put an end to that annoying thump comming out of the exhaust when i idle or whenevr the revs come down after shifting.  PLease help.

boosteds14 · 02-13-2002, 02:40 PM

i got the same problem my self, yet i have 72lbs. injectors and turbo. anyway, i found out that i was running rich. did you touch the fuel system at all. do an air/fuel ratio test, maybe you are running rich. another tip that i used was to lower the gap on the plugs. that may help a little.

what octane fuel do you use?

Art · 02-13-2002, 03:14 PM

93 octane.
But yeah that could be it now that you mention it.  A while back I had to use 89 instead of 93 and it did not do it as often or any at all if i remember right.  would it be advisible to use 89 octane fuel to stop the misfire, or keep using 93.

wherezmytofu · 02-13-2002, 10:04 PM

if your cars still misfire with 93 octane then the problem isnt predetenation.........since your cars r turbo they probubly shouldnt be runing on stock timing...go to a shop and have you car hooked up to a knock sensor....and play with the timing until it is gone

wherezmytofu · 02-13-2002, 11:37 PM

well this just poped im my head............just get a msd btm..............im 89% sure it will fill the problem <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt=':p'>

boosteds14 · 02-14-2002, 09:03 AM

art-- is your car turbo? i thought it wasnt, i dunno! hehe
maybe i read something wrong.

if your car is turbo, then wherezmytofu is right if not, you dont use a msd btm

wherezmytofu · 02-14-2002, 04:30 PM

o i was under the imprssion that his car was turbo...if not btm no good..just hook up a knock sensor and fix the timing <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt=':p'>

S13Grl · 02-14-2002, 06:27 PM

I think he replaced the exhaust... with a stock one. Nothing to back that up 100%, but most mechanics don't carry Apex'i in their shops <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>. But you guys knew that already, right? <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>

Art, do test your air/fuel ratio and check your ignition timing. Also check your compression (should be around 150 or so). There's a billion things that could possibly go wrong... eliminate the little stuff first. And definitely don't go to 89-octane fuel.

Art · 02-17-2002, 08:20 PM

I just got my air/fuel ratio gauge set up and it says that when i idle that i'm at stoich.  But when I floor it it doesn't read rich, not even at wide open throttle.  i have a feeling that it could be my fuel injectors.

would having an intake, exhaust, plugs and wires, and a 300 zx fuel filter make the engine do this.  If so, will reseting the computer to acknowledge the mods do anything?<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'>?

p.s.- no i'm not turbo (I wish)

stix · 02-17-2002, 08:31 PM

have you checked your o2 sensor? mine was running real rich and it failed emissions. i replaced the sensor and everything was fine. they say u should replace about every 50,000 miles. hope this helps

gh6o6 · 02-17-2002, 09:10 PM

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Quote: from stix on 10:31 pm on Feb. 17, 2002
have you checked your o2 sensor? mine was running real rich and it failed emissions. i replaced the sensor and everything was fine. they say u should replace about every 50,000 miles. hope this helps</td></tr></table><span id='postcolor'>
you beat me to it
grab it with a vice grip (you will never get it with a wrench if you even have one big enough) and forcfully unscrew the dam thing and but a new one at the local auto parts store (oh but it first, then replace) if you want an explination of what this does i will tell you but im going to bed now i will post tommorow

camppain · 02-17-2002, 09:38 PM

an o2 sensor is not a tune up part like plugs air filter etc. that would be shotgunning it and i suggest you dont just go and buy any part you THINK may be causeing it.

my buddy did that to his se-r and still failed emissions a thrid time after i told him that wouldnt solve it

02-17-2002, 11:50 PM

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Quote: from S13Grl on 8:27 pm on Feb. 14, 2002
Also check your compression (should be around 150 or so). </td></tr></table><span id='postcolor'>

Just a quick correction..  S13 compression should be b/w 151-179
(I'm 100% certain on first number and 95% on 2nd)
This is on DOHC.  if he's talkink sohc, I'm not sure but should be same.

*ca18guy* · 02-18-2002, 07:21 AM

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Quote: from Art on 2:31 pm on Feb. 13, 2002
I replaced the spark plugs with platinum ones and put on magnecore wires. </td></tr></table><span id='postcolor'>

Just so everyone knows, platinum doe's not produce a better spark then a copper spark plug, aluminum isn't as good of an conductor. It's main good point is it's longevity, thats all I wanted to point out <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'> Sykikchimp I agree with you on your compression numbers.  Art, why not reset the ECU it's not exactly hard, if it fixes it then consider yourself lucky.

Art · 02-20-2002, 09:47 AM

ok, i;ll try resetting the computer.  How should i go about it?<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'>??

and also, is there any way to mess around with the air/fuel ratio or do I need and upgraded ecu for that?<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'>

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02-13-2002, 02:31 PM	#1
Art Join Date: May 2001 Posts: 17 Trader Rating: (0) Feedback Score: 0 reviews	hey guys, I'm having this problem with a misfire.  I had the timing checked by a mechanic and replaced the whole exhaust system and a new cat.  I replaced the spark plugs with platinum ones and put on magnecore wires.  After putting on my intake, the problem seemed to get worse, or louder.  Could it be my injectors (I've gone through a couple of bottles of fuel injector cleaner). I really need to put an end to that annoying thump comming out of the exhaust when i idle or whenevr the revs come down after shifting.  PLease help.

02-13-2002, 02:40 PM	#2
boosteds14 Zilvia.net Advertiser Join Date: Jan 2002 Location: CIPmotorsports Age: 43 Posts: 1,612 Trader Rating: (0) Feedback Score: 0 reviews	i got the same problem my self, yet i have 72lbs. injectors and turbo. anyway, i found out that i was running rich. did you touch the fuel system at all. do an air/fuel ratio test, maybe you are running rich. another tip that i used was to lower the gap on the plugs. that may help a little. what octane fuel do you use?

02-13-2002, 03:14 PM	#3
Art Join Date: May 2001 Posts: 17 Trader Rating: (0) Feedback Score: 0 reviews	93 octane. But yeah that could be it now that you mention it.  A while back I had to use 89 instead of 93 and it did not do it as often or any at all if i remember right.  would it be advisible to use 89 octane fuel to stop the misfire, or keep using 93.

02-13-2002, 10:04 PM	#4
wherezmytofu BANNED Join Date: Nov 2001 Posts: 1,873 Trader Rating: (0) Feedback Score: 0 reviews	if your cars still misfire with 93 octane then the problem isnt predetenation.........since your cars r turbo they probubly shouldnt be runing on stock timing...go to a shop and have you car hooked up to a knock sensor....and play with the timing until it is gone

02-13-2002, 11:37 PM	#5
wherezmytofu BANNED Join Date: Nov 2001 Posts: 1,873 Trader Rating: (0) Feedback Score: 0 reviews	well this just poped im my head............just get a msd btm..............im 89% sure it will fill the problem <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt=':p'>

02-14-2002, 09:03 AM	#6
boosteds14 Zilvia.net Advertiser Join Date: Jan 2002 Location: CIPmotorsports Age: 43 Posts: 1,612 Trader Rating: (0) Feedback Score: 0 reviews	art-- is your car turbo? i thought it wasnt, i dunno! hehe maybe i read something wrong. if your car is turbo, then wherezmytofu is right if not, you dont use a msd btm

02-14-2002, 04:30 PM	#7
wherezmytofu BANNED Join Date: Nov 2001 Posts: 1,873 Trader Rating: (0) Feedback Score: 0 reviews	o i was under the imprssion that his car was turbo...if not btm no good..just hook up a knock sensor and fix the timing <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt=':p'>

02-14-2002, 06:27 PM	#8
S13Grl Married to the Mob Join Date: Dec 2000 Age: 44 Posts: 3,670 Trader Rating: (0) Feedback Score: 0 reviews	I think he replaced the exhaust... with a stock one. Nothing to back that up 100%, but most mechanics don't carry Apex'i in their shops <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>. But you guys knew that already, right? <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'> Art, do test your air/fuel ratio and check your ignition timing. Also check your compression (should be around 150 or so). There's a billion things that could possibly go wrong... eliminate the little stuff first. And definitely don't go to 89-octane fuel.

02-17-2002, 08:20 PM	#9
Art Join Date: May 2001 Posts: 17 Trader Rating: (0) Feedback Score: 0 reviews	I just got my air/fuel ratio gauge set up and it says that when i idle that i'm at stoich.  But when I floor it it doesn't read rich, not even at wide open throttle.  i have a feeling that it could be my fuel injectors. would having an intake, exhaust, plugs and wires, and a 300 zx fuel filter make the engine do this.  If so, will reseting the computer to acknowledge the mods do anything?<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'>? p.s.- no i'm not turbo (I wish)

02-17-2002, 08:31 PM	#10
stix Leaky Injector Join Date: Sep 2001 Posts: 64 Trader Rating: (0) Feedback Score: 0 reviews	have you checked your o2 sensor? mine was running real rich and it failed emissions. i replaced the sensor and everything was fine. they say u should replace about every 50,000 miles. hope this helps

02-17-2002, 09:10 PM	#11
gh6o6 Zilvia Junkie Join Date: Oct 2001 Location: Dirty Jersey Posts: 550 Trader Rating: (0) Feedback Score: 0 reviews	</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Quote: from stix on 10:31 pm on Feb. 17, 2002 have you checked your o2 sensor? mine was running real rich and it failed emissions. i replaced the sensor and everything was fine. they say u should replace about every 50,000 miles. hope this helps</td></tr></table><span id='postcolor'> you beat me to it grab it with a vice grip (you will never get it with a wrench if you even have one big enough) and forcfully unscrew the dam thing and but a new one at the local auto parts store (oh but it first, then replace) if you want an explination of what this does i will tell you but im going to bed now i will post tommorow

02-17-2002, 09:38 PM	#12
camppain Will never get banned... Join Date: Sep 2001 Location: San Diego CA Age: 45 Posts: 1,510 Trader Rating: (0) Feedback Score: 0 reviews	an o2 sensor is not a tune up part like plugs air filter etc. that would be shotgunning it and i suggest you dont just go and buy any part you THINK may be causeing it. my buddy did that to his se-r and still failed emissions a thrid time after i told him that wouldnt solve it

02-17-2002, 11:50 PM	#13
Guest Posts: n/a	</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Quote: from S13Grl on 8:27 pm on Feb. 14, 2002 Also check your compression (should be around 150 or so). </td></tr></table><span id='postcolor'> Just a quick correction..  S13 compression should be b/w 151-179 (I'm 100% certain on first number and 95% on 2nd) This is on DOHC.  if he's talkink sohc, I'm not sure but should be same.

02-18-2002, 07:21 AM	#14
ca18guy Premium Member Join Date: Jul 2001 Location: Clearwater FL Age: 42 Posts: 3,226 Trader Rating: (0) Rides Gallery: ca18guy Feedback Score: 0 reviews	</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Quote: from Art on 2:31 pm on Feb. 13, 2002 I replaced the spark plugs with platinum ones and put on magnecore wires. </td></tr></table><span id='postcolor'> Just so everyone knows, platinum doe's not produce a better spark then a copper spark plug, aluminum isn't as good of an conductor. It's main good point is it's longevity, thats all I wanted to point out <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'> Sykikchimp I agree with you on your compression numbers.  Art, why not reset the ECU it's not exactly hard, if it fixes it then consider yourself lucky.

02-20-2002, 09:47 AM	#15
Art Join Date: May 2001 Posts: 17 Trader Rating: (0) Feedback Score: 0 reviews	ok, i;ll try resetting the computer.  How should i go about it?<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'>?? and also, is there any way to mess around with the air/fuel ratio or do I need and upgraded ecu for that?<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'>