Problem With Rb25 Neo

[Bronx]

hey all, dont know if you guys have ever had this problem, i cant hit rev limiter, i can hit 5500rpm and then the car just dies, throttle wide open, boost drops to 0 and car stops driving but still keeps revs to 5500rpm, the engine just stops pushing........no boost no pull no nothing, just stays there, with foot to the floor.

cant for the life of me figure out what it is.

but sometimes it does go away, but instead, at 5500rpm it cuts out for 2 seconds and then just keeps going as if nothing happened..

any helpful info would be great.

RB25 neo motor, no TCS in the car all stock besides exhaust and coilpacks.

[skylinesandman]

wat sort of ecu i had simalar prob with my 33

n it was the ecu cuttin out i put a nistune in n the car

goin better than ever

[Bronx]

stock ecu, nothing modded or boosted, stock as a rock

[045HOW]

coilpacks?

[skylinesandman]

yeah i got stock ecu too wit mild mods and my ecu

freaks out when i try tap into the boost i even tryed resettin it

but when i put a nistune in it runs sick

^^ or ya spark is breakin down coilpacks plugs

but generally when that happens its more of a stutter than a

complete cut

[045HOW]

but generally when that happens its more of a stutter than a

complete cut

yeah this.

[skylinesandman]

yeah this.

yeah if ya didnt pick up in the convo already

i diagnosed that prob i asked ya bout down to the ecu

put a nistune in and can play wit the boost without the fuel cut

\m/ \m/

[045HOW]

yeah if ya didnt pick up in the convo already

i diagnosed that prob i asked ya bout down to the ecu

put a nistune in and can play wit the boost without the fuel cut

\m/ \m/

rock on!

[Bronx]

no fuel cut though, it doesnt cut out, it just stops accelerating. boost drops, and it will just stay at 5500rpm, wont drop below that and wont go above that... bloody weird, cleaned AFM, new plugs, and new coils. checked for any leaks, nothing. reset ecu, nothing... im lost now.

if i didnt just get fired, id opt for a Power FC, but gotta save money now.

sticking wastegate maybe?????

also just found this out, it has one of 2 problems,

Problem 1: any gear it wont rev up past the 5-6k mark but if it does manage to rev normally, problem 2 occurs

Problem 2: 1st gear, revs and hits boost and its all normal, hit 2nd and it has a 1 second cutout at 5-6k rpm, change to 3rd and it will continually cut out 5-6k rpm...... and same in 4th, cant hit above 5k rpm in 5th, it can only get to 180kmh

so if its not problem 1 its problem 2...... pissing me off!!!!!! RAAAAGE QUIT!!!!

[Bronx]

might have fixed it, i reset the ecu, disconnected for 2 mins and now the problem has gone and car also feels alot better. lets hope it stays like that.....

[Galois]

Here's an easier way to reset the ecu, also a way of reading fault codes

http://www.skylinesaustralia.com/forums/topic/266512-reading-nissan-fault-codes-ecu-fault-codes-how-read-them/

[Bronx]

THANK YOU, ive tried finding that thread multiple times, but i guess im too retarded, never found it. haha. thanks for that

[Galois]

No worries mate, yeah I bookmarked that one asap, knowing full well I'd lose it otherwise

[Bronx]

oh, bad news for me today, i decided to install a boost gauge today to see what the turbo is running, as we all know i cant read or make out what the stock boost gauge says, it says -7 all the way to +7 mmhg, so connected the new gauge which is psi, i plugged it in between the manifold and purge valve, and took the car for a run, the boost gauge hit 13psi at 5000rpm in first and hit 15.5psi in 2nd and 16psi in 3rd. so if this is anything to go by, im pretty screwed.

all i did was disconnect the boost solenoid and did the constant 7psi trick as talked about, or so i hoped. guess it seems to be a 15psi trick instead.....

[Galois]

Are you sure you didn't disconnect your actuator hose? Sounds like it's just boosting infinitely. Do your best to keep it below 12psi until you get the problem sorted, I'd be babying it to be honest...

[Bronx]

i am babying it now, poor little ceramic turbo but doesnt boost beyond the 16psi, pretty weird... so i will connect the solenoid again and see what it runs to

[Bronx]

just changed back to original solenoid, and it runs back at normal PSI, 350mm/hg which is 6.8psi, so the original boost gauge is pretty spot on. before it went beyond the +7 on the boost gauge (700mm/hg= 13.5psi) damn!

[Galois]

So what exactly did you do? Could have been a mixup somewhere?

[Bronx]

so the 2 pipes that go into the solenoid, i originally bypassed, hose-solenoid-hose, i bypassed that and just connected the 2 hoses directly without the solenoid in the middle. thought it would just sit at 7psi like people said it would, but it didnt did it??

[Galois]

That's interesting. Try unplugging the stock solenoid power source, that should give you your wastegate pressure.

Edited August 10, 2011 by Galois