first of all, i'd like to apologze first hand about the grammar involved. me dumb. hehe. okay:

when i got the car, it was sorta running rough. shop told me that the ecu is learning so it might take a week before everything smoothes out. i was like...ok. oh, i have a g35c w/ TN st kit...the non cat version....dunno why. i didn't ask for a non catalytic version..oh well. noticed i was getting 21 AFR's at idle. I also noticed the service engine soon light on..but thought since i have the non cat version, its suppose to ccome on? when i took the car out and boosted it, i went up to about 8.5 lbs w/ like AFR's around 14ish. it boosted okay...and then on my way back the other direction, i guess my car hit limp mode. not sure what lbs i hit or the afr's...there was trafffic so i had to concentrate on driving. car surges slightly and i can't rev past 2K. it bogs out of gear sometimes also. it died out a couple of times. when slowing down and clutchin it in at about 2K. damn...had the car for less than a day. well, its going back to shop for sure. sounds like a possible exhaust leak also. question...i searched the forums and from what i found, to get out of limp mode, you just turn off the car...wait a few seconds and then restart it? and the car should run fine until you max out the maf again? 'cause after i restart it...it runs okay... i drive it carefully...not going past 2K...and then about 15 min or so...back into limp mode. does the SES have something to do w/ it. haven't pulled the codes from it yet...dunno how actuallly. but yeah, any help would be greatly appreciated. i have two jobs and this is my one and only daily driver. i might have to invest in a moped to get me around now just in case this ever happens again...which i'm sure it will. hawww.. ****.

 

Read the other threads. It's either an improper install issue or an maf issue.

 

Wow, what is going on with all this. My car also idles lean from time to time, in the 18.X's, and it idles rough when its so lean, I give it gas it richens up and its fine.

There is a very similar post to this in this forum-same issue, people say the MAF maxed out throwing your car into limp mode. On my car mine would stall, then it would fall to idle with no throttle response, and it turned out to be my throttle body failed. What year is your car? And for me it always happned after boosting. When your car stalls or acts funny do you get a VDC OFF and SLIP lights on your dash? Cuz I did....btw fix your exhaust leak I doubt you are that lean, 14.X A/F boosted would likely cause your motor to go boom.

And btw-isnt the flash supposed to clamp the voltage on the MAF so it doesnt max out and limp on us??

 

With your AFR don't get into boost without fixing the problem. If you are really seeing 14 AFR on boost that motor will pop any min. Please get it checked ASAP. Good Luck.

 

really....damn. so what kinda afr's should i be at idle and at boost. i pretty sure i saw 14...(15, 16) i saw for sure. my car is an '03 and no i dont see vdc off or slip lights on. damn this sucks.

 

You should be around 14.7 at idle and part throttle cruising. I see perfect cruising A/F's but lean idle by 1 point average at idle, I hover 15.3-16.3 a/f. Under load it honestly depends what else do you have done to the car. The more additional mods you run the leaner you will probobly be. Ideally imo you want to stay under 12:1 under WOT....btw it does sound like a MAF and not a TB issue like I had.

 

oh yeah, i forgot to say that my car is basically stock (engine performance wise). I did remove my resonator...thats it. i have a stock muffler, stock piping, stock engine.

 

Sounds like a boost/vacuum leak for sure. And theres no way that AFR is right...you wouldn't have a motor if it was. If you are is limp moding even while staying under 2k and driving you absolutely have a vacuum/boost leak somewhere. Have the shop double check all the clamps and make sure that they didn't crack the MAF housing...

 

MIA-I can relate to you thinking his A/F is off WOT, but this lean idle issue is now starting to become an issue for some people, including me. Have any ideas on that?

 

+1 take it to get a tune ASAP!

 

First off he's not just a little lean at idle...hes at 22 bro. There no damn way thats right. And 14s under boost? NO ONE is that lean under boost. His car has other issues. I'm not sure why your car is reading 15s-16s at idle. The only possible thing I can think of is the ECU is keeping the timing slightly advanced at idle to compensate for the 380cc injectors. Occasionally going a little leaner while sitting at idle isn't necessarily a bad thing. Its the ECU correcting for a LOT more flow from the 380s and trying to keep you stoich. Which is why I don't grasp your reading. The ECu is reading its O2s in closed loop and trying to keep you at 14.7:1. Its weird that you are stting dead on at 15.6:1 with occasional dips higher. The dips higher I can see as sometimes the ECU needs to bump timing, alter trim, etc to get you to 14.7:1 but your car is never getting there. Did the shop you dyno'd at happen to check your AFR at idle when they were setting up the dyno? If so was it exactly what your wideband is reading? I mean honestly being 1 point to lean at idle isn't going to do anything to the car. You already mentioned that when cruising the AFRs are dead on and that under boost you are just barely to lean. I'm sure the under boost part will be corrected when the new up pipe gets your boost to where it should be (8-8.5 PSI).

 

Right. Even with a kit that is managed by pre-programmed ECU reflash, the *first* thing you want to do is run the car on a dyno w/ wideband o2. This is the best way to tell you or your tuner if everything is functioning properly, or not.

 

Im not saying his a/f is dead on, we can pretty much safely assume its off by a few points due to his exhaust leak, but if hes reading 22, its likely doing what mine is doing, which is high 15's, to 16's then wanders into 18's and idles BAD, almost sounds like a misfire. Idle @ the dyno with a new O2 sensor for the start of the new year btw was dead on with my guage. Also read in another thread a guy with 18's idle-Im beginning to wonder if this is a common thing for certian cars/certain mods...

 

thanks for the reply guys. i'll take it to the shop once it opens. its like 8:34a in Hawaii and the shop opens at 9:30-10:00a. Dunno if you folks heard of this shop, its VAKAMON motorsports. they have a silver 600 HP G35 w/ the carbon hood, trunk, 18" volks, and one off suspension. they don't have a dyno though. the shop next door does which is how i think they tuned their G.

here it is:

http://www.jtuned.com/content/templa...d=281&zoneid=1

 

Hmm I guess its possible. Any commonalities between mods. I know you have the Crawford V1, JIC exhaust, and thats it for flow mods right? I wonder what the other guy had. His AFR is most certainly not even close to right and lets be honest, hes going into limp mode without ever going above 2k rpms...hes got a vacuum leak somewhere. Like I said its not uncommon for the ECU to advance the timing a bit at idle to correct the trim at idle but it shoudl always go back to 14.7:1. My car sits there at idle and occasionaly advances to 16:1 at idle but then goes right back to 14.7:1. Thats what it should be doing as far as I know. I've talked to a few other TN kit guys who say its the same on their car. Occasionaly the ECU overadvances the timing to compensate for larger injector flow and get you stoich but everyone always gets back to 14.7:1. If you and someone else are not getting there we need to see whats common between you two and uncommon to us and see what the issue is..

One thing I should note is that my car did this stock, after added exhaust, and then again after I added the plenum. Its never changed on my car...

 

Exactly, and yes, all I have for additional flow mods are exhaust and plenum. Only time I sit at 14.7 @ idle is after boosting its good for a few seconds then it starts going lean...

 

Thats exactly what my car does but mine reads 13s coming off boost...then goes to 14s....with occasional dips to 16...Do you remember the other members name?

 

No-its been posted elsehwere I forgot, but it was recently, he complained of what seemed like a MAF issue but said his car was idling in the 18's and rough

 

I'll try to find it right now...

 

my idle gets lean too but I am pretty sure its just the injector issue. I dont worry too much about it because it is pretty much momentary, only at idle, and always seem to return to home (around 14.7). We'll see what happens with bigger injectors and the UTEC soon.

But mine350z I am sure you have a leak and you should be very careful with a/f that high at boost.

OT:
Did anyone get the new WG relocation pipes yet? pics?