So I took the nitrous kit and Nismo intakes off my 07 350z. I put the stock fuel rail back on and the stock intakes. When I started it up it ran really rough at idle...sounded and felt like a cammed out V-8. It revs fine and smooth after about 2500rpms but as soon as it drops below 2k it starts to spit and sputter. I'm thinking there is air in the fuel rail? I don't see a purge valve to purge the line. The Mafs look great. Can anyone help? I even tried looking in the FSM and didn't see anything about this, maybe I overlooked. I let it idle for about 30 seconds and reved it up a couple of times thinking it may work itself out, but it must have been running really lean...the exhaust was really hot, didn't smell like fuel like normal cold start, and had rotten egg smell which should be the cats right? I'm just hoping that I didn't burn something out letting it run lean that long. Any help would be great! Thanks guys.

-Scott

 

check the injectors' harness plugs.

 

+1, also check that the injectors are not leaking at the fuel rail or intake manifold and all coils and both throttle bodies are plugged in. The fuel rail doesn't need to be bled.

In addition, make sure the plenum is tightened down and not leaking.

 

Thanks for the advice guys. I never touched the injectors or TB's or plenum. It was just Nismo Intakes and a wet Nitrous kit. I'm going to double check all these just to make sure. How would the fuel rail not need to be bled? Just curious because we don't have a return fuel system...so wouldn't air in the fuel rail cause it to idle rough and run lean until the air is out? My friend had this problem with his tahoe before he put a return on. I just really don't wanna mess the car up. Thanks again.

-Scott

 

How can you put the stock fuel rail back on (you're implying that there was another fuel setup other than stock) without removing the injectors from the old setup and removing the plenum to get to them?

The fuel system is pressurized with 6 outlets (injectors) and the fuel in all the lines and injectors is replaced with new fuel constantly. Air would work itself out of the rail or lines in a short time of running if this were the case.

I removed my fuel rail and installed new injectors in a few different Z's, all of which had empty fuel rails when they were reinstalled on the car. None of them have had this issue.

Also, I highly doubt that you did any damage idling lean for a minute. It would just cause misfires rather than damage.

You said the MAF's look great so I'm assuming you have made sure they are both plugged in all the way?

 

Maybe I have it mixed up. The "fuel rail" that I am talking about is the one you have to tap to run a wet shot of nitrous. The rail is about a foot long and goes from the left front of the engine to the center front of the engine. I will try to get pictures. Been sick for the last couple of days so haven't messed with it. I'll try starting it up today and letting it idle a couple of minutes to see if it works itself out. I didn't have this problem when I put the tapped rail on...of course it was tapped so it had an escape route for the air. I did check the mafs 3 times, they are good to go as far as I can see...and they are plugged in. The car runs smooth at 2500+rpm...it's just under 2k that it lopes and misfires.

-Scott

 

Not very familiar with nitrous setups but make sure there are no fuel leaks as well. Sounds like it may be an air leak though.

 

Did you try doing a throttle body position + idle air relearn procedure? (search forum for more info)

 

you don't have to bleed anything. turn the key on, drive. done

 

<---- is dumb. I dropped a screw for the MAF and never put that one in. I didn't even think about it going all the way through the intake so it has a little hole there, which would be a leak lol. Gotta find it or get a new one ASAP! I am probably paranoid, but I hear like a rod knocking in the back passenger side of my engine when the hood is up. I know it's probably nothing. Plus I'm sure the 3-4 month old gas in the car isn't helping it out any. Good looking out guys! Thanks. And if anyone has an extra MAF screw hit me up!

-Scott

 

gas is gas. ppl worry aobut that crap but my car sat for 9 months and fired right up. was it the best thing to do, prob not, but it'll run enough to wear that tank out and put fresh in. I just didn't get into boost until the gas was gone.

 

I'm not too worried about the gas. I'm going to go see if I can either find the screw I dropped or get one from a junkyard from a Z or G. It should be good to go then! Now I gotta get pictures of my nitrous kit up and get it sold so I can get more parts for my bike lol. Anyone know anyone interested hit me up! Thanks guys.

-Scott

 

Your problem sounds like a burned valve to me. But if it idled fine before then you should try all the ecu reset/re-learn procedures as mentioned above.