R33 Gtr Not Holding Boost (standard) After Exhaust Install?

[GD51LA]

i installed an exhaust to my car today, it drove fine all day untill about an hour ago it started missfiring. now the boost wont go past the middle of the standard gauge its not miss firing any more and its still not boosting??

what do you think it could be?

[R.3.2.G.T.R]

stock turbos??

[GD51LA]

stock turbos??

Yes stock turbos..

[GTRsean]

Game over.... Ceramic wheel is now down your exhaust somewhere most likely.

Better go shop for some new turbos......

I got -9's as I don't trust the ceramics, even if they ain't blown, you can do some engine damage and end up with few scored bores after the ceramic dust from the failed turbo does it's thing.

Has been covered in other Topics.

Good luck with your turbo choice

[UNR33L]

could it be something as simple as a vacuum leak? or a split pipe? maybe get a mechanic to look at it before you go buying anything.. much smoke?

[DVS JEZ]

Pull the e haust off just before the cat. See if the cat has melted or if there is any parts of ur turbo sittingthere.

I did a servce on a mostly stock r33 yesterday the guy only just bought it. Was supposed to hav beennever boosted. When i dropped the exhaust at the cat there was a shattered exhaust turbine sitting therefrm a previously blown turbo. So much fo never been boosted

[paulr33]

intercooler joiner has come apart

check them all

[GD51LA]

I don't think it's the ceramic wheels, it's on standard boost

Where do I find the vacuum hoses? How many are there?

[DVS JEZ]

Take the cat off and check it hasnt melted.

Does ur car idle fine?

[GD51LA]

The cat is brand new.

There is a small spool hesitation when it comes on..

[DVS JEZ]

Drop the cat and check its not melted and there is no turbine peices sitting there

[GD51LA]

I groped the cat and found nothing inside

One guy told me that if it was the turbo wheels that were damage It would be lagier but it's not lagier at all??

[DVS JEZ]

thats a good thing then, atleast now you know and can move onto the next stage, elimination process.

next easiest thing take it into a good tuner and put it on the dyno,

[GD51LA]

We found a unusual hiss it sounds like a vacuum leak coming from under the plenium

Is there vacuum hoses on that area? Where exactly? I tried spraying carnie cleaner all over the plenium but the noise didn't go away?

The sound is below the middle of the plenium (I think that's how u spell it)

Anyone had this prob before?

[UNR33L]

there is a lot of vacuum pipes under the plenum have a look / jack the car up or get it on a hoist, a big light and the Mrs makeup mirror and check them all out, also check your boost gauge T piece mine split and had similar problem to this, fixed up and running so much better

[Ruff Ryda]

there is a lot of vacuum pipes under the plenum have a look / jack the car up or get it on a hoist, a big light and the Mrs makeup mirror and check them all out, also check your boost gauge T piece mine split and had similar problem to this, fixed up and running so much better

+1 Listen to this guy. My boost leak was a split hose connected to the T piece that joins up to the stock boost gauge in my 15. Something so small can really mess up the fun experience of having a turbocharged car. However my symptoms was that it would still spool but car wouldn't pull and I was nearly reading 0 on the gauge.

What other modifications have you got? Installations of aftermarkets parts including exhaust can spike the boost levels up.

What boost controller you running and is it functioning correctly? I would recommend a decent EBC like GReddy Profec II Spec B

However, failing the above, if your injectors were already close to full cycle then you're hitting full cycle when full boost hits. They reason why it's only started to do it is because the ECU being self managed has allowed the extra boost but now not enough fuel can actually be delivered assuming you have the stock ECU. Even if you have an aftermarket ECU I would recommend at least a fuel pressure regulator upgrade and a retune. The best course of action would be to get the mods you want done to it with a set of Tomei 555cc injectors or 740cc if you want to make big power on a stock engine and then take it to a reputable tuner. Stock, PowerFC or NIStune, your call.

[GD51LA]

why would it need extra fuel? its all standard ecept for exhaust. no extra boost at all. or maybe a pound or two from the new exhaust?

the car was runing fine for hours and then it just died

ist boosting normaly just less..

[Ruff Ryda]

why would it need extra fuel? its all standard ecept for exhaust. no extra boost at all. or maybe a pound or two from the new exhaust?

the car was runing fine for hours and then it just died

ist boosting normaly just less..

How big is exhaust? 3"?

It's a natural occurrence when you get more flow because of less restriction. Truth is the only reason you could be burning more fuel is because the of the increased spike from the turbo by 1 or 2 PSI as it's reading more air thus adding more fuel (need to check AFRs). This would only be a problem when you already have nearly maxed out the injectors and the ECU has permanently set the option to allow more fuel which takes some time to adjust (say an hour or 2). I'm not saying this is your problem but it's a possibility that may fall in your category. If it's stock as you have indicated just then, it's not very likely (unless for some reason you have unusually small injectors or a faulty fuel pump that conicidently decided to play up).

I would check all vac lines first as advised. If nothing just get it dyno'd and AFRs checked. AFM could even be kicking the bucket or an O2 sensor is playing up.

Definitely invest in an EBC when you get funds for it, well worth it.

Good luck.

Edited September 7, 2010 by Ruff Ryda

[GD51LA]

I had a smoke test done and we couldn't find a vacuum leak anywhere

Could the computer be in some sort of safe mode? I did put injector cleaner in there, could that have been the problem? When I took the plugs out they were a little white. Did the injector clean lean it out and trigger safe Mode?

It has a new tank of fuel in there now but the boost is still at 70% or so

[MrStabby]

why would it need extra fuel? its all standard ecept for exhaust. no extra boost at all. or maybe a pound or two from the new exhaust?

the car was runing fine for hours and then it just died

ist boosting normaly just less..

If you have a boost leak the air measured by the AFM will be more than what is actually being pushed into the motor (as the leak is downstream of the AFM) and therefore you get rich mixture. Vacuum and boost are carried in the same lines at different times depending on what the motor is doing.

Did you fix the hiss? No point in doing anything else until that is sorted.