HELP: Getting misfires on Cylinders 1,3, 5 only

Originally Posted by Andrew's Z

Hey Guys,

Hoping you can help me out here. I have a 2012 Nissan 370Z with 52,000KM the following mods as it relates to the powertrain:

- Stillien Gen 3 Intake
- Berks HFC
- Meisterschaft Exhaust
- UpRev Tune

I was doing some highways pulls a few weeks ago and ran through way more gas than I expected and ended up experiencing loss in throttle (I know I was low on gas)... Limped to the gas station filled up all was well for a few days.

This is where my problems began, I stated throwing the great P0300 Code and threw a P0301 code the following day (never appeared again) for C#1. This started to happen more frequently especially when I was harder on the throttle so a few days later I decided to change the spark plugs since I was also noticing a periodic rough idle.

After changing the spark plugs with Denso factory replacements, cleaned TBs, and MAFS the idle issue was resolved car felt better and the code did not pop up the day I took it out for a road test, I was pretty hard on it and no code.

The following day I was driving to work and the code reappeared but this time it was only the flashing CEL, once again P0300.

So I checked the freeze frames for misfire counts and here is what I noticed, only bank 1 (passenger side) is misfiring (cylinders 1,3,5), the opposite bank looks to be running fine.

Misfire Counts Before and After spark plug change
Cylinder 1 :355 (before) | 139 (after)
Cylinder 2: 0 | 0
Cylinder 3: 178 | 69
Cylinder 4: 0 | 1
Cylinder 5: 23 | 11
Cylinder 6: 0 | 0

What do you guys think could be causing this issue, when this all first started I thought it was fuel related maybe the fuel filter or pump from running it low on gas but after seeing these results I am a little confused where to start looking.

Appreciate all your help and advice in advance!

P.S. Not sure if this is related but I having been throwing the Post O2 sensor code for over 10,000km before this problem started, only assumed it was just the HFC doing their job...

Originally Posted by Ghostvette

It's quite possible to still have a fuel delivery issue, since you said it got better after fill up. Look behind the passenger seat, and pull the carpet up on the shelf that's back there. You'll find the access point for the fuel tank. Follow the FSM and take a look inside. You might find the fuel pump has fallen down into the bottom of the tank. Phunk at CJM has the solution to your possible broken fuel hat.

Originally Posted by Andrew's Z

Thanks Ghostvette! I have definitely experienced the right hand turn fuel starvation issue when I'm @ 1/4 (maybe even 1/2) tank or less but 1/2 or above I haven't noticed this issue.

With that being said, if it were a fuel starvation issue how could only one side of the engine be experiencing issues? This leads me to believe there could be an issue with the fuel delivery to that side (fuel rail? but unlikely) or maybe even the cat for the passenger side causing an increase in back pressure leading to miss fires.

Any idea how I could troubleshoot to determine if its the cat?

Thanks!

Originally Posted by Ghostvette

Problems with cats usually show up as excessive heat on that side of the motor. The cat will literally glow red, especially if it's almost plugged. There will be a noticeable problem with the way the car runs, it usually won't run at all. If the hat has broken on the fuel pump, you will get decreased fuel pressure to the fuel rail, because the pump could be pinching the line from the tank to the outside fuel line to the engine. It's a place to start.

Originally Posted by Andrew's Z

I'll to pull this out this weekend and check to see if there are any issues, I assume I am looking for the broken posts to the fuel hat as seen in the image below.

http://www.the370z.com/attachments/e...e-img_2653.jpg

Any other suggestions would be greatly appreciated. There has to be something that's driving the passenger side of the engine to mis and not the drivers side, since there is only one fuel line to the Engine Bay I can't imagine its anything before the engine bay.

Keep the suggestions coming!