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CEL misfire 1 and 2

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Old 10-24-2007, 04:36 AM
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cruz106
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Default CEL misfire 1 and 2

B4 anyone roasts me please know I have been searching as many threads as possible for 2 days.

I just bought the car from INFINITEABYSS 3 -4 weeks ago...2003 350z APS sT w/UTEc on a non-built motor.

I am getting the P03011 and P03012 codes for a misfire on the 1st and 2nd cylinder. HOWEVER, no rough idle and no noticible loss in power. I live in San Antonio, TX and it has been in the 80's. On Monday a cold front came in and Tuesday early morning and Wednesday early morning the temperature was in the 50's...SUDDENLY, no CEL.

I am 98% certain the plugs need to be replaced because of the mileage on the motor and I will be replacing them Friday. Okada coils are <30 days away. UtEC map selctor set cool days, hot days, track days

Question is: TOO RICH for outside daily temperatures, timing issue, or am I totally off? Suggestions for a tuning shop in San Antonio, TX.
Old 10-24-2007, 06:39 AM
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athenG
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Random misfire is going to be part of your life now so just accept it. Mine only happen on cold start and maybe one every month or so. Every FI'd car should have an OBDII reader so you can just erase it.
Old 10-24-2007, 07:12 AM
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Ahsmo
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Originally Posted by athenG
Random misfire is going to be part of your life now so just accept it. Mine only happen on cold start and maybe one every month or so. Every FI'd car should have an OBDII reader so you can just erase it.
+1 I have had these codes from the first crank on my FI set up
Old 10-24-2007, 08:02 AM
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gothchick
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HKS makes an ignition amplifier that may help misfires.

http://www.intensepower.com/hkstwpodliii.html
Old 10-27-2007, 05:18 AM
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if you have an individual cylinder misfire, you should try checking and changing the plugs first. if not that, it could be coil.

an individual cylinder misfire usually means there is some problem. the random misfire code P0300 is no big deal, though.

BTW, do you ever see your Check Engine Light flash while you are WOT? it flashes when you have a specific cylinder misfire. I had an issue with cylinder 5 when I have TN ST on my car. Every since going greddy TT, the issue went away. My CEL would flash when I was in the upper rpms of a 5th gear WOT run.
Old 10-31-2007, 07:03 AM
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KPierson
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Originally Posted by gothchick
HKS makes an ignition amplifier that may help misfires.

http://www.intensepower.com/hkstwpodliii.html
There has been no evidence provided that the HKS unit will eliminate the misfire codes associated with the UTEC.
Old 10-31-2007, 07:09 AM
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rcdash
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Does detonation cause misfire codes? (sorry if slightly O/T; just curious if that may be a heat and/or hot spot related event in the cylinder)
Old 10-31-2007, 07:14 AM
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gothchick
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Originally Posted by KPierson
There has been no evidence provided that the HKS unit will eliminate the misfire codes associated with the UTEC.
Hmmmm... It worked for Stormcrow on a GreddyTT.... Maybe someone could pm him for further details.

Last edited by gothchick; 10-31-2007 at 07:48 AM.
Old 10-31-2007, 11:20 AM
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KPierson
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Originally Posted by gothchick
Hmmmm... It worked for Stormcrow on a GreddyTT.... Maybe someone could pm him for further details.
Did it? I haven't read any confirmations, just people threads about people who spent $500+ for it and had the same CELs.
Old 11-01-2007, 08:09 AM
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gothchick
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Looks like you may be right. It worked for a little while, but then he eventually got the code again...

https://my350z.com/forum/showpost.ph...7&postcount=40
https://my350z.com/forum/showpost.ph...7&postcount=79
https://my350z.com/forum/showpost.ph...8&postcount=84
https://my350z.com/forum/showpost.ph...3&postcount=89
Old 11-01-2007, 08:57 AM
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Kevin,

did you ever get around to installing your other UTEC to see if it is a UTEC issue.

It could be a UTEC issue, but I am more inclined to think it has to do with the the lasrger injectors not working as well at idle conditions along with cooler sparkplugs.

I think the majority of the misfires come at startup and idle. People have said that if they run 2 steps colder plugs, they get a huge number of misfires at starup.
Old 11-01-2007, 10:26 AM
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No, I haven't installed the 2nd UTEC. Can't seem to find the time, and its starting to get cold here.....
Old 11-01-2007, 01:29 PM
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Originally Posted by KPierson
No, I haven't installed the 2nd UTEC. Can't seem to find the time, and its starting to get cold here.....

come on.....it is only about 1/2 an hour to swap it out inthe G.
Old 11-01-2007, 03:39 PM
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Yeah, a 1/2 hour for the actual swap and then 1.5 hours to get the dash to fit perfect back together!
Old 11-03-2007, 04:38 AM
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cruz106
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My codes were for cylinders 1 and 2...they were not random. I spoke to Shariff and we agreed t ostart with the plugs and then look at the coils. We agreed it "likely" was not the injectors or plugs because they were replaced back when the turbo went in. I got my 1 step colder plugs 2 days ago. I put them in yesterday at noon and then reset the CEL. No codes after driving all over the city last night and early this morning. I have not opened her up to WOT. Inspection of the plugs showed a white residue around the electrode and carbon around the ceeramic base. I took an OHM meter to the coils...each coil has 3 tabs...mine are numbered 1 2 3
Resistance Coil #1 Coil #2
1 / 2 0 0
1 / 3 8.5 8.5
2 / 3 7.5 7.5

I am going to follow up and see if my other coils have similar variances or if they have a closer resistance reading to each other. This may be the issue.
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