Help! Loss Of Power R33Gtst

[sam_c]

Hi guys,

I have a S1 R33gtst thats recently developed a loss of power problem.

About a month ago it developed a misfire so I did a full service and replaced the coilpacks with splitfires as well as the spark plugs and it was driving like new again. Last night however my problems have returned it feels sluggish and struggling to come onto boost. There is no misfire now but it just has no guts. If i try and put my foot down it eventually comes onto boost and can reach redline but it takes a while.

Best way to desrcribe it is as I am speeding up from say 2nd to 3rd with the boost on vacuum (ie 25-30% throttle) it sounds like it is on full boost and as i change gears the blow off valve lets go as if i am on full boost. Kinda feels like something is being restricted. I am thinking it may be a leak in my piping or dirty air flow meter but would appreciate any help pinpointing the problem. Havnt seen any smoke out the exhaust so i dont think the turbo has let go, but I should mention that it makes a bit of a rattle when on boost.

I am only running 10psi on stock turbo with fmic, avcr boost controller, bosch 040 fuel pump, emanage ultimate ecu.

Any help would be much appreciated!

[jjman]

i dont know avcr's but do they give a constant display of boost pressure (like the greddy profec's do)

if so what are the numbers you are reading?

also turbo's dont usually 'rattle' when on boost... many people have complained of a brief high pitched squeek but never a rattle...

[sam_c]

i dont know avcr's but do they give a constant display of boost pressure (like the greddy profec's do)

if so what are the numbers you are reading?

also turbo's dont usually 'rattle' when on boost... many people have complained of a brief high pitched squeek but never a rattle...

Yeh they do, and the reading matches my other boost gauge aswel so i dont think its a problem there. Its set to 10psi and it will eventually boost up that far but it takes its time getting there. Been installed for 6 months with no probs.

And i know what you mean about the turbo noise a mate of mine has had a few let go on him and its not the same noise at all. This one doesnt sound quite that serious though its sounded like that for almost a year now with no problems.

I cant think of why it would run shit, be fixed and run great for two weeks then in one day deteriorate back to how it used to be :S

[mad082]

ok 2 things, the rattle on boost may be a sign that there is a damaged exhaust manifold gasket or broken manifold studs, or possibly the turbo has come loose on the manifold.

the boost issue could be caused by the leaking manifold, but it also sounds like an issue i had with a turbosmart dual stage manual boost controller. what was happening in my case was that there was a T piece with a 1 way valve in it. 1 hose went to the intercooler, another to the wastegate and the 3rd to the controller. the issue was that there was also a tiny bleed hole in the T piece. long story short, the bleed hole was blocked so when you lifted off the wastegate was still being held open by the pressure between the 1 way valve and the wastegate. this meant that when you changed gears the next gear had no acceleration and took for ever to build boost.

i would be more inclined to say you have an exhaust leak or possibly an intake leak. if it was an intake leak then the car should be running rich though and it may break down (misfire) when you floor it.

[PM-R33]

As Marc said. Rattle could be an exhaust leak or could be a collapsed cat.

[sam_c]

ok 2 things, the rattle on boost may be a sign that there is a damaged exhaust manifold gasket or broken manifold studs, or possibly the turbo has come loose on the manifold.

the boost issue could be caused by the leaking manifold, but it also sounds like an issue i had with a turbosmart dual stage manual boost controller. what was happening in my case was that there was a T piece with a 1 way valve in it. 1 hose went to the intercooler, another to the wastegate and the 3rd to the controller. the issue was that there was also a tiny bleed hole in the T piece. long story short, the bleed hole was blocked so when you lifted off the wastegate was still being held open by the pressure between the 1 way valve and the wastegate. this meant that when you changed gears the next gear had no acceleration and took for ever to build boost.

i would be more inclined to say you have an exhaust leak or possibly an intake leak. if it was an intake leak then the car should be running rich though and it may break down (misfire) when you floor it.

Thanks, I had a look today and have noticed that it is very oily underneath where the rocker cover is attached on the exhaust side, could this be a further indication that it is the exhaust manifold gasket or just a bad seal around the rocker cover? Had a quick check of all intake piping and couldnt find any obvious leaks but i will need to do this properly over the weekend and take a good look at the exhaust manifold gasket. no misfire to speak of even at 100% throttle since the splitfires went in though and no excess fuel consumption or blackening of my rear bumper from the exhaust so i am inclined to think its not running excessively rich so not an intake leak from what you are saying?and the cat is under 6 months old high flow so i doubt it is the problem

Edited June 1, 2011 by sam_c

[mad082]

the oil will just be from the rocker covers. extremely common problem.

when you check the manifold, just look and see if all 16 manifold studs are there (2 per cylinder). it's common for a few of them to break off, thus resulting in a leak as well as a gasket rattle.

[Roffy92]

Hey,

im having a similar problem, it feels like shes not as punchy as she was when i baught her about 4 weeks ago.

im thinking it could be a piping leak or some sort of leak, its a stock s1 R33 gtst everything running stock atm (7 p.s.i).

i would be more inclined to say you have an exhaust leak or possibly an intake leak. if it was an intake leak then the car should be running rich though and it may break down (misfire) when you floor it.

i am getting a few misfires but not under power, only when i release the throttle (i suspect that could be a F'd O2 sensor because im getting terrible fuel efficiency as well)

my boost gauge reads like it did when i baught it but it just feels sluggish when the gauge is telling me its at full boost.

what should i check first?

cheers guys