Slow R33

[rb25]

so its not at any particular rpm, but more so when the engine is under load?

I think it could be:

Could be the air volumes being measured by the ecu are wrong, this being caused by a boost leak or a fault in an electrical component (AFM, AAC, O2). either way, the air thats getting pumped thru the engine isnt matching what the ecu is reading. I dont think it would be a dirty pod filter or a collapsing pipe between the AFM and turbo because you're making full boost.

OR

Fuel system problem. when the engine demands alot more fuel when on increased boost from cruising or idle, the fuel pump might be bad and not be keeping up, or the lines/filters might be partially blocked only allowing enough fuel thru for idle and cruise mode....

So I'd check: AFM, O2 sensor, AAC valve - these bits you may have cleaned but could they just be broken? Fuel pump, all fuel lines, fuel filters, fuel injectors. All air lines and hose clamps, fuel pressure reg. to plenum line in particular. Alot of this shit you've done so on goes the process of elimination!

hope i could help

cheers

rb25

[rb25]

Other than that, I'd take it to a specialist and get it data-streamed. That'll pick up most problems. Shouldn't take anymore than an hour to go through all the menus and tests so 55bux i guess.

[skyline33]

thanks rb25, where are the o2 sensor, aac valve located and how do you check if they are faulty??

[skyline33]

thanks rb25, where are the o2 sensor, aac valve located and how do you check if they are faulty??

also how can i test the injectors if they are blocked or not

[Trotts33]

Had my own exhaust shop for 10 years, came across this problem quite a bit, blocked or broken Cat, extreme restriction in system, just a thought, maybe worth checking.

[skyline33]

thanks i'll keep that in mind

[skyline33]

thanks i'll keep that in mind

[rb25]

O2 sensor

[rb25]

Trotts33 - good idea. some simple things can be overlooked sometimes eh...

and the aac valve

[rb25]

im not sure how to test them except with the nissan hand computer data-streamer thingo. sorry....

[skyline33]

do you mean nissan Consult??

also the cat apparently has been replaced during compliance last year, if it has been replaced can it still be blocked taking into consideration that the car hasn't been driven more than 5000kms

[rb25]

yep - the consult

[Trotts33]

The Cat should be OK but a dose of super fuel or a bad misfire can destroy a cat in minutes, a solid knock can also break up the guts and send fragments into the system. A good exhaust shop should be able to pressure test before and after the cat and any other muffler in the system. On the cheap grab a dud cat from a complier, Knock the guts out, bolt on and test run, same deal if you can borrow a known good system to test.

[skyline33]

thanks guys for all your inputs but i took it to a guy i know who has a diagnostic computer and he plugged it in and said that the knock sensor needed reseting and it needed a tune.

does anyone know where the knock sensor is located? and how they tune the cars without an aftermarket management system.

[rb25]

have you tried just resetting the ecu?

[skyline33]

my friend actually didn't try that but its all ok now. but i'd be intrested to know how it can be done manually with a diagnostic tool

[skyline33]

Originally posted by skyline33

thanks guys for all your inputs but i took it to a guy i know who has a diagnostic computer and he plugged it in and said that the knock sensor needed reseting and it needed a tune.  

does anyone know where the knock sensor is located? and how they tune the cars without an aftermarket management system.

anyone??

[wrxhoon]

there are 2 knock sensors on the block under the inlet manifold . one is near the front and 1 near the back of the block .u cant adjust the sensors , maybe they had some dirt on them and he cleaned them .

[skyline33]

can these be reset them with a diagnostic tool?

[strutto]

They can be reset with a paperclip IMO...