Car Misfires/stutters After Turbo Install (33 Gtr)

[R33GOD]

Got my gtr back from my mechanic and i took it for a test drive and there is a hesitation/splutter/missfire at cruise between 2 and 3.5k rpm.

I was told just to reset the ecu so it would go away. I reset the ecu and the problem is still there. Its very annoying.

if i put the foot down it drives normal. weird. Is this normal because the turbos are bigger and the ecu cant read air fuel properly?

mod list

2860 -7's

stock ecu

stock fuel pump

stock dumps

3in exhaust

Edited February 1, 2009 by R33GOD

[R33GOD]

does it 70% of the time by the way

[The Dan]

You could possibly have a TPS fault, Injector or fuel pump issue, AFM needs a clean. etc. etc.

Clean the AFM's, reset the computer again and make sure all the AFM's are plugged in correctly.

How long did the car sit while the turbos were being fitted?

[R33GOD]

everything has been unplugged for about 4 weeks.

i sprayed some contact cleaner on the connections and im gonna let it sit til they dry.

just disconnected the batt terminals also. Will connect everything up in 30 mins.

Edited February 1, 2009 by R33GOD

[R33GOD]

just came back from a short drive and what i did didnt fix the problem

[DECIM8]

how bout fouled plugs, or ungapped plugs running high boost

[KiwiRS4T]

Got my gtr back from my mechanic and i took it for a test drive and there is a hesitation/splutter/missfire at cruise between 2 and 3.5k rpm.

I was told just to reset the ecu so it would go away. I reset the ecu and the problem is still there. Its very annoying.

if i put the foot down it drives normal. weird. Is this normal because the turbos are bigger and the ecu cant read air fuel properly?

mod list

2860 -7's

stock ecu

stock fuel pump

stock dumps

3in exhaust

I had the same problem when I got my new GCG - put it down to compressor "surge" so I(I have a Jaycar EIBC) turned the boost down to around 10psi at 2500 -3000 and built upto 16psi from 3500 on - that fixed it.

p.s. you should def think about a vipec (or link) computer

[The Dan]

Didn't he say it was while cruising? he shouldn't be making any boost while cruising.

[R33GOD]

Sparkplugs are fine and gapped perfectly

[R33GOD]

still have this problem now my idle is jumped up to 1100-1200 rpm.

and sounds like its misfiring slightly at idle

Edited February 3, 2009 by R33GOD

[Julz89]

hows the idle speed motor give that a clean?

also check for vacume leaks as in vacume hoses on inlet manfold, boost controller etc etc.

[Brezza]

hey mate!

i feel your pain!!

i got some 2860r-5's installed yesterday and its doing the same thing popping, stuttering and missfiring between 2000-3500rpm at half throttle.

its running 13.5psi and the plugs are supposed to be gapped properly.

plus its only making 213rwkw

and it ran really lean at higher boost.

list of mods

R32 GTR

stock internals

stock ecu, fuel pump, injectors

2860r-5's

mines dump pipes

front pipe

high flow cat

3in cat back

pod filters

anyone with any ideas what it could be?

mechanic said it could be the injectors sucking in air?

Brezza

[Brezza]

i called Brett at Graham West Workshops and he said it could be the oxygen sensors in the exhaust?

they could be around the wrong way and the car could be adjusting the wrong cylinders for the wrong turbos?

he said he seen this problem before with the car stuttering and that was the problem.

maybe you should try checking for this?

i am gonna get the mechanic to check this, hopefully fingers crossed it is something simple like this and i can start making some real power.

Brezza

[R33GOD]

u shouldnt worry too much. my tuner told me it can be quite normal on cruise as the mixtures are lean already and by adding bigger turbos ( more breathing) it just leans out abit more on cruise.

mine goes down to about 5 - 10% of the time now. i let my car warm right up before i drive it and i hardly have a hicup.

i have my car on about 12 psi and its fine even if i put the foot down. dosent ping. As for my idle i adjusted the idler set to low and i dont have much idle jump anymore. 900-1000 again.

I also just realised, well a friend pointed it out that i have a huge hks fmic on my car. (knew it wasnt stock but woo hoo HKS!!)Could this be causing some of my hiccups on cruise too?

Also abit off topic but would the HKS cooler i have now make a noticable difference on overall power compared to the stock R cooler?

Edited March 5, 2009 by R33GOD

[MrStabby]

u shouldnt worry too much. my tuner told me it can be quite normal on cruise as the mixtures are lean already and by adding bigger turbos ( more breathing) it just leans out abit more on cruise.

Your tuner's a crackhead;

- at cruise the throttle is limiting the air to the same amount that would have been flowing to achieve the same speed with the other turbos

- you wont be on boost at cruise, so those bigger turbos wont be doing anything

- the AFM would read any extra air in that came in and adjust fuel accordingly

- the feedback provided by the o2 sensor is used to further adjust fuel and achive stoic

- mixtures are stoic at cruise, not lean

But i'm in IT so what would I know?

[R33GOD]

hmm.. i was just relaying what ive been told.

Im getting my tune done soon so il see if the problem goes away. Got me puzzled now

[Mike__]

Take your AFM's off and clean them as suggested in post #3

my 32gtr developed the exact same problem. Sometimes on v light throttle or cruising (no boost) everything went dead, then would stutter/hesitate for a second or 2 then feel normal again. Got on the forums, learnt how to do a self diagnostic check on the ecu. Came up with a fault code from the AFM's. Took them both off, pulled the covers of as suggested in the DIY section, all connections/solder were excellent. Noticed the actual 'element' part of the afm in the airflow was covered in oil from accululation over the years.

Removed the flywire @ both ends, sprayed a heap of RP7 to clearn them up the elements and noticed there red . Reinstalled AFM's and instantly the throttle response felt a lot more crisp. 4 months later and ive never experienced a hesitation.

Hope this helps

Mike

[Brezza]

Hey mate,

i just went to the Mechanic last night and i've discovered its my O2 sensor that it buggered.

being a GTR and having 2 the mechanic unplugged one of them and it got worse, so he plugged it back in and unplugged the other and its running a lot better now. still not 100% still stutters a little at times.

so now i guess i am up for some O2 sensors.

but i think i am gonna need to clean my AFM's, when i put my pods on i noticed that they were a little bit oily and the K&N pannel filter i had in the stock air box was covered in that filter oil, there was even a pool of it in the bottom corner.

the K&N pannel would've filtered good because everything was stuck in it!

like the bloke above said too, the O2 sensor ensures that the mixtures are correct by measuring the exhaust gasses and adjusting fuel to ensure that the mix is correct.

its kinda a pain that i have to change the O2 sensors because of the extra $$$ i gotta spend. but at least i know what the problem is now.

Brezza

[JonnoHR31]

afm's dont like oil....

Edited March 6, 2009 by JonnoHR31