help diagnosing problem with rb25

[tomj]

i have a 4 door aussie 31 with a series 2 rb25 in it, ie self igniting coils, and pink lablled afm.

been on road a long time, but ive just got it a month odd ago.

did cooler and zorst a week and half ago. garret cooler, and 3 inch turbo back system

since then, whenever its on hard load, mainly on a cool night, it will begin to pop and stutter around the 5000rpm mark, and keep popping as long as foot is down, bring it onto boost slowly and not full load and its ok

plugs are 7 range ngk's, 100km old now, gapped to .6

it will barely do it during the day , when it is warmer.

fuel pump is a 500hp walbro and its rich, the flames and black rear bar are testemant to that as well as the alluring aroma of fuel that follows car around.

possibilites

coil

afm

boost cut

any more?

[R33vit]

What are you boosting too. Sounds like ECU cutting fuel due to over boost (boost cut)

Is it a stock ECU?

[tomj]

stock ecu... im not sure what boost it is making to be honest

its about 12 psi

[TurkeySlapper]

Hey, mine does something sililar, aussie 31 series 2 rb25 fmic all else stock, when nailing it in the dry it will run ok half the time and piss and fart the other half, but in the wet as it starts to spin in 1st or 2nd and the revs climb too quickly it just starts to rev then completely dies in the arse, then thinks about it, revs back up then dies again... veeeeerrrryyyy frustrating.

Tomj i feel your pain

[tomj]

mines different to take bro, if i break into wheelspin , it will smash limiter and pop massive flame most of the time, so times it will fall over

[meggala]

boost cut tom you need an ecu or fuel cut defender

and dont be a cheap skate wind the boost back to stock till you if a boost gauge

seriously a cheap boost gauge cost me a motor so imagine what no boost gauge could do

meggala

[TurkeySlapper]

yeah thats what i meant, if you hit the limiter too quickly, which happens when spinning the wheels, then it just shits itself. but if you acclerate full throttle without spinng it doesnt cut out but surges randomly thru the rev range. why oh why.

[tomj]

boost cut tom you need an ecu or fuel cut defender

 

and dont be a cheap skate wind the boost back to stock till you if a boost gauge

 

 

 

seriously a  cheap boost gauge cost me a motor so imagine what no boost gauge could do

meggala

yeah ill do that, see what boost its making

whats stock boost cut on a 33 auto ecu?

[blind_elk]

Can I suggest a heat-range 6 plug. And open the gap up a bit (0.8mm seems to be the norm)

[JH32]

tom just out of interest is your car a manual or an auto ?

[tomj]

manual Jimmy

blind_elk, the plugs where 6 series before, and missfired also , so i know it isnt plugs

[blind_elk]

How much boost is it running?

[JH32]

manual Jimmy

is nice !

[BBQ]

I think the stock boost cut is somthing like 16 or 18 psi. can't rember exactlly.

[N I B]

Nissan boost cut has nothing to do with boost but airflow and fitting better turbos etc can bring it on at low boost.