90 na z miss randomly - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

dsmjlo · 03-30-2011, 07:11 PM

ok so i just got this car for a steal... lol um it has a random miss fire comes and goes i cant pin point if its at the same time or wat. before i go mental figuring this out is there any well know problem i can check for. other question is there a vin on the motor anywere. the dude i got it off of says the motor was replaced in 02 ........ i was told the 90 model had problem with the head ? id appricate any help or advice thanks ahead of time!

Sileighty_85 · 03-30-2011, 07:17 PM

there were a few issues with the early 300zx, main one is probably the Injectors.
Nissan wired it to where the injectors had power 24/7 which ended up killing injectors over time.

forgot about the others though, Im if you google 300ZX common issues you will find out

joesmith · 03-31-2011, 09:12 AM

common misfire are caused by spark plugs...
check plugs and make sure it's gapped properly.

sl0th · 06-20-2011, 01:47 AM

could misfire also be caused by slightly off timing???

Supergoji · 08-09-2011, 10:20 AM

yes that could also be the case.

this website has a wealth of info that every Z32 owner should know.
http://www.ttxtz.com/tech.html

run your codes and do this.

the 6 P's: proper preparation prevents piss poor performance

mnmax · 08-24-2011, 12:07 PM

i also have a 90 n/a z... when i first got it, it had the same issues. just like sileighty said, my problem was with the injectors. it would be intermittent at times then all of a sudden stop working. my suggestion would be to swap to the later style injectors and upgrade your ignition system if in your budget.

Alexlua · 09-09-2011, 01:22 AM

Did you ohm out the injectors? try doing that first,

On early Z's the harness isn't all that great. They decided not to put "gaskets" ( a tiny piece of rubber around the edge of the plugs inside) 94+ Z's ave them as wel as the new efi harnesses, anyway no gaskets in the connectors lets moisture in and corrodes the connectors causing a bad connection. I like to use pb blaster and spray all the connectors and sensors with it and using a pick I scrub off all the corrosion (normally turns green). then I use the same pick to close in the connectors and give better contact once I plug them all back up.

Try to ohm out the injectors first that way you make sure they're all good and if that's the case do what I mentioned above and let us know how that goes.

03-30-2011, 07:11 PM	#1
dsmjlo Join Date: Mar 2011 Location: moon twp pa Age: 35 Posts: 1 Trader Rating: (0) Feedback Score: 0 reviews	90 na z miss randomly ok so i just got this car for a steal... lol um it has a random miss fire comes and goes i cant pin point if its at the same time or wat. before i go mental figuring this out is there any well know problem i can check for. other question is there a vin on the motor anywere. the dude i got it off of says the motor was replaced in 02 ........ i was told the 90 model had problem with the head ? id appricate any help or advice thanks ahead of time!

03-30-2011, 07:17 PM	#2
Sileighty_85 Post Whore! Join Date: Dec 2006 Location: Misawa, Japan Posts: 6,815 Trader Rating: (8) Feedback Score: 8 reviews	there were a few issues with the early 300zx, main one is probably the Injectors. Nissan wired it to where the injectors had power 24/7 which ended up killing injectors over time. forgot about the others though, Im if you google 300ZX common issues you will find out __________________ 後輪駆動車１番 1989 Built SR GT2871R -363whp 1998 S14 W/RB25- 250ish (For Now) 1986 SR86 - 200ish 1990 R32 GTR - 320hp Don't Buy Engines from JDM-Online http://zilvia.net/f/businesses/207457-jdm-online.html Don't Buy XS-Power or SSAC Shit

08-09-2011, 10:20 AM	#5
Supergoji Zilvia Member Join Date: Aug 2011 Location: westchester NY Age: 32 Posts: 232 Trader Rating: (4) Feedback Score: 4 reviews	yes that could also be the case. this website has a wealth of info that every Z32 owner should know. http://www.ttxtz.com/tech.html run your codes and do this. the 6 P's: proper preparation prevents piss poor performance __________________ www.NYZC.net

08-24-2011, 12:07 PM	#6
mnmax Zilvia Member Join Date: Nov 2007 Location: in the Marines now... upstate NY Age: 36 Posts: 194 Trader Rating: (0) Feedback Score: 0 reviews	i also have a 90 n/a z... when i first got it, it had the same issues. just like sileighty said, my problem was with the injectors. it would be intermittent at times then all of a sudden stop working. my suggestion would be to swap to the later style injectors and upgrade your ignition system if in your budget. __________________ GIGGITY GIGGITY GIGGITY GOOOO!!!!

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03-31-2011, 09:12 AM	#3
joesmith Join Date: Jan 2010 Location: SL,UT Posts: 18 Trader Rating: (0) Feedback Score: 0 reviews	common misfire are caused by spark plugs... check plugs and make sure it's gapped properly.

06-20-2011, 01:47 AM	#4
sl0th Join Date: Apr 2011 Location: Bay Are Age: 29 Posts: 10 Trader Rating: (0) Feedback Score: 0 reviews	could misfire also be caused by slightly off timing???

09-09-2011, 01:22 AM	#7
Alexlua Join Date: Sep 2011 Location: Los Angeles Posts: 8 Trader Rating: (0) Feedback Score: 0 reviews	Did you ohm out the injectors? try doing that first, On early Z's the harness isn't all that great. They decided not to put "gaskets" ( a tiny piece of rubber around the edge of the plugs inside) 94+ Z's ave them as wel as the new efi harnesses, anyway no gaskets in the connectors lets moisture in and corrodes the connectors causing a bad connection. I like to use pb blaster and spray all the connectors and sensors with it and using a pick I scrub off all the corrosion (normally turns green). then I use the same pick to close in the connectors and give better contact once I plug them all back up. Try to ohm out the injectors first that way you make sure they're all good and if that's the case do what I mentioned above and let us know how that goes.