Rough Start - Something Seems Wrong

DIGItonium

I'm starting to wonder if my stock FPR is starting to fail. Lately I'm starting to smell some fuel when I give it at least half throttle, and under 3k RPM I'm smelling some fuel through the vents. Throttle response is getting worse especially under 4k. It just ramps up slower than usual, and is a bit rough or wants to stall. The engine has died on me a couple of times after coming to a complete stop. Idle would drop pretty low and stall. Rough starts is occasional, so I wonder if low fuel pressure is the culprit.

__________________

RBfastback

having that same problem just now as I sti in my car.
drove home fine, jacked one side of the car up to check if I hade the old style brake lines w/ the 90 deg bend or the newer( I have the older) and let the car down and now it won't start...
last week nissan replaced my MAF's after fighting with them to do it under warrente for 30min then the finally agreed to do it. my cars a 2013 nismo with 25k on it and the oil level is fine. WTF

DIGItonium

I just got done changing out the spark plugs (fouled after 45k miles), cleaned the intake plenum, throttle bodies, etc. I don't have anymore issues starting the car (so far), and it seems to run pretty nicely. I just need to figure out if and where the vacuum leaks are since the idle is bouncing a bit.

__________________

RBfastback

it may be something else for me, still hasn't started. just starts then stalls even when engines cold.
sel is on, and giving it gas when starting it dose nothing.
just got towed to nissan since I'm still in warrantee

Jordo!

You might need to go though an idle learn procedure -- otherwise, spray carb cleaner around the IM and see if the idle revs up.


I'm guessing either bad cam or crank position sensor, or a VVEL issue.

Although it could be something more prosaic like bad MAF's or O2's. Another possibility is plugged cats, if you have them.

EDIT: Wait it was fine until you had it on a lift and just checked the brake lines??? You might have a damaged wire or connector to a primary O2 sensor. Otherwise, no idea. Why did you have them replace the MAF's before?

Good luck!

__________________
Enjoy it. Destroy it.

RBfastback

no not a lift, just floor jack on one side of the car in the proper jack location to take a 1 min look.
last week I got the service soon light and had a code for maf sensor. nissan wanted to void my warrantee cuz of my gen 3's but after some arguing they replaced both. still have been having the random limp mode problem but other then that it was running perfect all the way home.
I have art pipes also so no cats

DIGItonium

I did the following: throttle closed, accelerator pedal, and idle volume learn (twice). The next morning I redid the zip ties and switched out a hose that wasn't fitting the barb properly. It idled and warmed up nicely, which it didn't do that the day before. After a test drive idle bounces ever so slightly at times. This is something I dealt with before doing the major work, but I will continue to monitor and trace any leaks. At least it's not throwing P0507.

So far so good... engine is running smooth, and so far no warm start issues.

__________________

Jordo!

When you say code for MAF, do you mean out of range or high fuel trims? You might just need a tune.

If it dials itself out, it could be lingering fuel trim that will eventually self correct (although I think you can clear those out with cipher). If intermittent, I'd try cleaning MAF sensors with that CRC spray.

If still no change, then there may be a small deformation or pinhole somewhere causing an occasional vac leak.

I actually had that problem on the OEM intakes! I over-tightened a hose clamp and managed to ever so lightly deform the plastic of the intake tube

If you still have any of those little L shaped resonator boxes in the intake to IM tract, I'd check those too.

__________________
Enjoy it. Destroy it.

RBfastback

the 2 codes were p0101 and p010b.
either way nissan replaced both MAF's.
I have an uprev tune from feaver racing (zfeaver) and I got the tune the same time I got the gen 3s, gthaus exhaust and art pipes. so my afr was perfect as of about a year ago when I got the tune. originally I had k&n filter but last month I changed them to the aem dry flows that stollen sells for the gen 3's and also put on HydroShield from injen.
it's at nissan now, i gotta drive this in the mean time lol

DIGItonium

There's no L-shaped box for the intake anymore since it has the GTM kit. Gosh I'd hate to look for pinhole leaks. I'd rather it be the vacuum lines than the gaskets, though. It's a pain to have to take everything back out. I'll give it another run this afternoon as a sanity check since I did slightly tighten a few bolts in various areas... hopefully I didn't end up in your situation from over tightening.

__________________

RBfastback

apparently it was my driver side throttle body causing me the problems, they replaced it an everything was covered under warranty.
here's the work sheet

car runs amazing now.
I usually have the throttle lag/limp mode problem every day sometimes every other day but so far so good.
will de if that was also the problem

Jordo!

^^^^ Ah, Martin probably tuned you, right? He's a good buddy of mine -- your tune should be good

Looks like you had a bad throttle body

I've heard of that happening on these cars -- rare, but it happens. Unless you had the TB's off that's almost certainly just a random part failure and it's highly unlikely you will ever have the issue again.

The code is for a bad IAT sensor -- also weird, but both failures were on same bank so looks like you just had bad parts from the factory.

Glad it got resolved!

__________________
Enjoy it. Destroy it.

RBfastback

yeah martin seemed like a cool guy!
I've never taken them off before so I think I just got "lucky".

thanks for all the help with problem solving! i always appreciate it!

it sucked driving the murano, no fun factor

pbs370z

not normal

__________________
'10 Z, Sport Pkg 6 MT, Stillen Brake Cooler, Z1 Oil Cooler w/Setrab 25 row/Mocal T-stat, Southbend Clutch w/light wt Flywheel.

defesio

two months ago this problem appears in my Z, I 've been reading all the forums looking for the solution , and after talking with my mechanic, he suggested to clean the MAF, Throttle Body and the K&N filtre.

The MAF was OK, but the throttle body was really dirty, lot of oil and dirt. After a nice clean my Z is running great, and the problem never come back.

Its been 5 days without a problem.

Hope this help someone.