Issues: (related and maybe unrelated)

Specs: 03 MCS, 123k, CAI, 16% pulley, one-ball mod.

- poor acceleration from a stop. Acceleration seems more sensitive in neutral than when in gear.
- dead spots in rpm power band. Typically starts at 3.5k but seems o flat line a bit,especially on WOT.
- slightly shaky idle. After warmed up, revs between 750-800rpm. Bad?
- rough starts. Takes a couple turns to get up and running. Very rarely, I'll start it up and the rpms barely reach 1000. Normally goes up to 2k and falls back to idle.
- passenger IC boot is perspiring oil, done hear vac leak from it tho.
- NO CODES!


What I've done:

- new plugs (iridium range 7) stock coil and cables. Cables are two years old.
- fuel filter
- belt and tensioner(needed to be replaced anyway)
- cleaned air filter
- cleaned Map and tmap maybe 8 months ago.
- Ecu reset
- boost seems good, 14-15 psi at 6800 rpm.
- had sc service and new Valeo singl mass not long ago. Clutch pedal has funky popping feeling mid travel. Clutch engages super early.


Bah.

 

Also, crank pulley seems to be intact still but is the original pulley.

 

I'd be looking at the intercooler boots, and the by-pass valve. You say you changed your fuel filter - might possibly be the fuel pump, or dirty injectors even.
fwiw, you won't get a vacuum leak from your boots, it's under pressure, not vacuum.

 

Bypass spring still works, but it doesn't feel any different in tension when I compared it to other r53. Colin greene said that start up with low initial rev was an air leak. There are so many places to check. I guess I could try a smoke test.

Hesitation in guessing would be more relates to fuel?

 

Replace that intercooler boot. It's probably leaking under pressure but not under vacuum, so you can't hear it when standing in front of the engine.

 

When I replaced my by-pass valve I noticed that the rubber tube was 'worn out' - but you're right, so many things to test.

And I agree about the fuel delivery seeming to be the potential culprit - it's all spark/air/fuel, and you've got 2 of those handled...

 

+1
if the boots are oozing oil....they are done..get new ones. bet they are stiff, and not sealing.

 

Hey Zippy, they're barely-year-old silicon boots but maybe that's the problem is that I'm using silicone and not OEM ha ha Ha

 

Unfortunately those silicone rubber boots are very hard to get on right...
But if oil is present, I bet it is folded over and leaking...a boost leak explains your symptoms... And you have oil seaping out...that is a telltale sign...there is very little oil in the intake charge...just the blowby pcv oil...so if there is a bit showing, it means a pretty big air leak....
Costs you NOTHING too investigate....
Always do the cheap, simple, easy stuff first...and you have a clue pointing you to the boots too!!

 

Indeed. My boost is showing up as 14 psi at redline with a 16% pulley. The boot is just sweating it's not actually leaking it's got like a little bit of perspiration on top in the morning

 

Some say the silicone intercooler boots are not nearly as good as oem, they look good so people use them. I'd stick to the oem. If a vendor made different color stock style boots that would be nice.

 

And I agree. They were a money saver at the time. But is boost of 14-15 psi with 16% pulley normal? Does that explain hesitation at take off?

 

That sounds about right, the 02-04 mcs makes a little less boost than the 05-06 with the jcw superchargers in them.

 

When mine had hesitation and power loss it was because the timing chain had jumped a tooth on the crank, this was seriously underpowered tho so doesnt sound like thats your problem.

I had the timing re done and still had hesitation and flat spots but had abit more power. The problem turned out to be a cracked piston and a cracked valve. This was all coupled with the engine drinking copious amounts of oil. All of this was probably because the timing jumoed.

Other things id check are
Stretched belt
Coilpack
Leads
Map sensors
Throttle body

 

Thanks, Eric!