Help With R32 Gtr Boost Problem New Here!

[awoken]

hi all

im new here and have owned a r32 gtr for almost a year now and Love IT!!! i live in new zealand and dont really know anyone who can actually help me so thought someone here can being such a awesome site in all.So the mods done are very little which are catback exhaust,apexi pods with adapters,and removal of the boost restrictor now running 1 bar thats it.The problem im having is i'll start my car up let it idle warm then drive,now when driving for the first 10mins it'll run awesome hitting 1 bar exactly on my apexi boost gauge and holding,but after a few times of putting my foot down and running mint it will all of a sudden it will only boost .7 bar and no more and sorta feels like your driving with the handbrake on.It will boost 1 bar again the next day i drive it but always only for the first few putting the foot downs then back to .7bar which sucks.So i did the self diagnostics on the ecu and it gave me the flash code 34 which is the Knock Sensor code.So i rang nissan and said to the mechanic what the code was and he said that i need new knock sensors and that it doesnt mean my engines knocking ??? but it doesnt sound right i thought that code meant that your sensors are picking up knock so the ecu is cutting boost??? Ive tried new afms,a chipped ecu,new spark plugs gapped to .7mm. also with no result.its weird cos it doesnt blow smoke doesnt make any apperant knocking sounds by ear anyway idles and runs good and has good oil presure etc I cant figure it out

thanks in advance anyone who replies

[Bronx]

my guess is your knock sensor is broken, your engine doesent need to be knocking, but also sometimes the knock sensor if too loose or too tight, will give incorrect readings.

you can test if your knock sensor is working or not, grab a wrench, and when your engine is idle, hit your engine block close to the knock sensor, you should feel your rpm drop or go higher etc. if that doesent work, do the same thing again, but when reving at about 2,5-3k rpm. if nothing happends, you could have a defective knock sensor

hopefully that will help

Jean

[awoken]

my guess is your knock sensor is broken, your engine doesent need to be knocking, but also sometimes the knock sensor if too loose or too tight, will give incorrect readings.

you can test if your knock sensor is working or not, grab a wrench, and when your engine is idle, hit your engine block close to the knock sensor, you should feel your rpm drop or go higher etc. if that doesent work, do the same thing again, but when reving at about 2,5-3k rpm. if nothing happends, you could have a defective knock sensor

hopefully that will help

Jean

hey man thanks for your info will try tonight and let you know what it does . really appreciate your feed back thanks!!!!!!!!!!!!

[R32GTR-1]

hi guys this is the exact issue im having with it running 1bar then dropping back to roughly .7 after 10-15mins of driving. I havnt done an ecu sefl test but I will tomorrow and see if it throws the same code. I know this is an old as thread but just wondering if anyone else has had this same issue and solved it.

[XKLABA]

Both cases, if you turn the car off wait five minutes turn it back on does it go back to 15psi or stay at 10psi ?

As for knock sensor it could be as simple as one has vibrated loose

[R32GTR-1]

nah it stays at low boost until its fully cooled down again. say at least a few hours or the next day.

[R32GTR-1]

I should add I have only bought the car a few days ago. it has k&n pod filters, -9 turbos, full exhaust and the boost restrictor removed. now when I picked it up it had the standard airbox and I was unaware of the upgraded turbos as was the previous owner to my knowledge as he had it advertised as standard. when I went and looked at it the first time it was warm so when I test drove it it was only getting the low boost which I thought was normal. then I got it brought to a worskshop to have a look underneath and do a comp test and once again it was warm and running low boost which I though was normal. after I fitted the pod filters I took it for a drive and noticed it was hitting 1 bar, then I noticed it dropped back to half. so today I had a look and found the restrictor had been removed, also I had a good look at the hotside and pulled the inlets right off and this is how I discovered the upgraded turbos. It also has hks actuators. I had a look at all the actuator lines and they all seem fine. I have currently just hooked the actuators straight up to the manifold (bypassing the solenoid etc) to see if it make it just stay at low boost but havnt driven it since as it was hot,

Edited August 20, 2014 by R32GTR-1

[XKLABA]

Sean, what cat have you got in it ?

I would think once you turned it off it would reset itself and give you 1 bar again, so my best guess is yours is something mechanical

To run wastegate pressure just unplug the boost solenoid, it needs power to open

[Gareth]

Not any help but, How did you know the turbos were -9's?

[R32GTR-1]

im not to sure what cat it is. it is aftermarket, it looks like a highflow item but I havnt pulled it off and had a look. as for how I could tell they were -9s I could see the comp cover had some different marking on them compared to what standard turbos look like so I pulled the intakes and cooler piping off until I could read one of the little metal id tags on the core of the turbo(s) and googled the part number. also since installing the pod filters I could hear the turbos spinning down once I turn the car off every so slightly which made me think they must be ballbearing.

drove it this morning with the solenoid bypassed and it was 7 psi, pulled over after a few mins, hooked the solenoid back up and bang straight to 13-14psi and same thing after about 10-15 mins of driving back to 7.

Edited August 21, 2014 by R32GTR-1

[Gareth]

as for how I could tell they were -9s I could see the comp cover had some different marking on them compared to what standard turbos look like so I pulled the intakes and cooler piping off until I could read one of the little metal id tags on the core of the turbo(s) and googled the part number. also since installing the pod filters I could hear the turbos spinning down once I turn the car off every so slightly which made me think they must be ballbearing.

Thanks, have been wondering whether mine were actually -9's (as i was told when i brought the car) or something else, so was just curious to how you knew.

When you unplug the solenoid shouldn't you just be getting standard wastegate pressure? and isn't that 10psi? i know when i turn my boost controller off i get around 10-11psi

Edited August 21, 2014 by Gza36

[XKLABA]

Factory wastegate is 10psi

I think he said he has aftermarket ones so they can be anything, my old -7s had 7psi actuators

[Ben C34]

I'm not sure if the ecu will drop the boost if it detects pinging but it's a strong possibility.

Do you know what pinging sounds like?

[jiffo]

I guess it's still the stock ecu.

When cold, the stock ecu retards the IGN and so you will see higher boost.

It's very obvious, even without planting the foot you'll hear the turbos working harder and the BOV's puffing on gear changes.

But as soon as she reaches operating temp, it's back to stock IGN timing.

There was a thread a few months back where blokes with Nistune complained of a similar problem.

A kind person showed how to alter some parameter and then no more cold engine IGN retard.

Might be worth a thread dig.

[R32GTR-1]

ok guys can update this a little bit now. yes I know what pinging sounds like and I havnt heard it ping at all. also tonight it seemed it didn't need to cool down for it to change to high boost again. left home went to a mates house about 30 mins away, sure enough about 15 mins into the drive went to low boost. fot to his house sat out the front with the car idling for maybe 2 mins waiting for him to come out, left his house turned onto the main road and bang high boost again, again lasted about 15 mins then gone. then later on in the night, driving went to low boost, parked up for 10 mins or so, went back out and high boost. so that's kind of thrown the hot/cold thing out the window. and yes I have aftermarket actuators which are set to 7-8psi it seems.

another thing I noticed tonight unsure if related or not, when im going up a hill and in 5th gear doing say 80kph (so high load on the motor) the turbos shuffle?? almost sounds like the blow off valves constantly going off. like choof choof choof choof if that makes sense lol. seems somewhat strange to me and im sure it isn't right. ive had turbo cars previously and never had anything like this but this is my first twin turbo car. no matter how much I put my foot down it wont make boost just does the turbo shuffle, I have to drop back a gear and then it will pull fine.

[R32GTR-1]

Ok guys I have found a big connection between the low boost and the turbos shuffling when going up hill etc. So when its running low boost the turbos also shuffle like crazy. When high boost I can not get it to shuffle at all even if I try. So im thinking maybe its a timing issue ? Would also make sense as to why when ib low boost it also feels sluggish off boost even.

[R32GTR-1]

just thought id update this for anyone else that might have a similar issue, it ended up being a faulty knock sensor, replaced both knock sensors with 2 second hand ones and problem solved.