Rb25 Boosting Problems

[mitchy_]

my engine has decided to go into a sort of 'limp mode'...

it idles quite rough (searches between 1000-1500rpm, sounds like a big lumpy cam..) and on a cold start it just feels like a rb20e, and wont boost much, however the guage is showing its hitting the usual 13psi.

the exhaust is also very loud and droney at the moment too.

normal driving, if you gently increase the revs, it goes to about 4000rpm then starts knocking (engine light flashes with PFC), and if you increase the revs too quick, it gets to positive pressure, then feels like it kills off all the power, and the exhaust just gets loud and droney again.

i have a stock AFM in it at the moment, but ive got a Z32 afm which i tried swapping it over to the other day, and that just seemed to make the problem worse, it was stuttering at low revs and i could barely get it back home from 200m up the road.

any idea's?

[Cubes]

Vacuum is normal on idle?

[mitchy_]

yep, sitting on about -70kpa, which it always has.

[paulr33]

what do you see in ETC, SENSOR SW CHECK

can u get a photo? any sensor names in black? any relays going on/off rapidly (black dots flashing)

the engine check light flashes

if afm max warning is enabled and you max the afm

if knock max warning is enabled and you go past 60 knock

if inj max warning is enabled and you go past 98 inj duty

if any sensor fails or goes out of bounds

so it might not be knocking it could be a sensor failing

if a sensor fails it throws the engine check light and its name goes highlighted in the ETC, SENSOR SW CHECK screen

at idle

MONITOR

4 CHANNEL

AIRFLOW

INJDUTY

IGNTMNG

KNOCK

give it a rev a few times

what values do you see ?

[mitchy_]

oh yes.. forgot to mention... no hand controller for the PFC.

also, the check engine light is permanently on, but flashes when it knocks.

i tried putting the stock ECU in, but the car wont start, just cranks over.

[paulr33]

ok if the check engine light is always on a sensor has failed

i would suggest checking the obvious stuff

afm, water temp, tps etc

without a hand controller its difficult to diagnose

do you know someone local with a 25 PFC hand controller?

you shouldnt be loading the engine up (boosting it) with the check engine light on

[mitchy_]

yeah, im trying to source a hand controller at the moment.

sensor failed would indicate why the stock ECU doesnt work aswell?

afm seems to be fine, water temp is being registered at 1/3rd (as per usual) on the dash so i assume that works?

[paulr33]

no the dash guage is different to the water temp sensor

so its possible the guage can still work, but the actual sensor is toast

when my water temp sensor died (the ecu one) my car wouldnt start

can you get access to a consult cable?

if you can plug in the stock ecu, turn car to ACC

run consult, it will tell you what it toast and why the car failed to start (it actually lists it)

[mitchy_]

ah ok.

dont think i can get a hold of a consult cable, but the PFC hand controller will still tell me which sensor has died (or not working properly), wont it?

[paulr33]

yeah the fc controller will tell you what you need

[mitchy_]

update: it stalled at a set of lights, and wont restart now... i guess whatever sensor was dying, is dead!

updated update: that was the fuel pump i swapped over, it runs again, same as usual though, sourcing a PFC controller on the weekend.

[mitchy_]

ok well i got the pfc controller today.

plugged it in, and checked the sensor sw check at idle, it showed 'bost' (boost) as highlighted, but the rest are fine (engine light stays on all the time)

then i took it for a drive, so other sensors were highlighted, and then i did the airflow/injduty/igntiming/knock check, nothing seemed to be maxing.. airflow rear 1800-2000 or something similar? injduty never reached near 100%, igntiming stayed about 30degrees, but dropped to 20 as it started flashing the engine light, and the knock bar got up to about half way, but thats it.

so now im confused.

[drf76]

ok well i got the pfc controller today.

plugged it in, and checked the sensor sw check at idle, it showed 'bost' (boost) as highlighted, but the rest are fine (engine light stays on all the time)

then i took it for a drive, so other sensors were highlighted, and then i did the airflow/injduty/igntiming/knock check, nothing seemed to be maxing.. airflow rear 1800-2000 or something similar? injduty never reached near 100%, igntiming stayed about 30degrees, but dropped to 20 as it started flashing the engine light, and the knock bar got up to about half way, but thats it.

so now im confused.

im not sure if it would fix it but it might have the powerfc boost control option on, that would cause the engine light on and may run rough but then again u said u tried the standard ecu and it didnt fix it, true??