Power Loss....

[Jakiro]

Alright, keep in mind that this is a freshly re-built engine (break-in has been completed), and the turbos have at the most 8000 miles on em.

Soooo, I was merging onto the highway this morning and decided to open her up a bit. I've only hit "full" boost a handful of times at this point, so I'm still a little bit apprehensive about the entire car. Anyways, did a 2nd gear pull at roughly 10-ish psi to about 5500 RPM at about 3/4 throttle (everything a-okay, and pulling VERY hard), shift into 3rd and do the same. It lags until about 4000RPM (holding constant at roughly 5psi), then spools up to roughly 10-12 psi, pulls hard, then all of a sudden the BOV's go off and the car stops accelerating (still running though). At this point I immediately pull over, and notice my exhaust note has changed (sounds almost raspy...kind of like a HUGE exhaust leak), the car will not idle (it never did, due to some smaller vacuum leaks), but revs freely- there is ZERO smoke coming from the exhaust. Anyways, i turned it off, took a quick look under the hood and it all appeared the same - but I had to get it home as I don't carry tools with me. I get back in it, fire it up, and head off.

On my way back, I noticed the car has a huge loss in power, and my clutch is very very soft (but still engages/disengages without a problem). I was afraid to boost it, but it is pulling itself out of vacuum without any real problems. At this point I haven't had a good chance to look at it (I'm pissed off at myself more then anything), but I need some suggestions on where to start looking.


To summarize, my symptoms are:
-Bov's went off without my input
-Car has a HUGE loss in power
-Extremely soft clutch when car is running - stiff when off - still engages w/o problem
-Odd exhaust note - zero smoke though
-Oil Pressure is still very good
-will not idle -> dies very quickly
-free-revs without a problem, but when a load is applied it feels like I'm towing a house
-It seemed to go back to normal for a split second when making a left turn - as long as it's above 3000-ish rpm.


I haven't had a chance to run codes yet, but I will very soon....First thing to do on the list is do a compression check....I hope to GOD I didn't loose a cylinder....I'm thinking this sounds more like a major vacuum leak...no?
__________________

[-JK-]

I'd check for vacuum leaks first, if it is, it should be a leak after the throttle bodys. The only way your BOV could open would be if your plenum pressure is lower than your intake, so I'd start by checking out the plenum/bov connections.

The clutch booster runs from the intake manifold too, so it seems to me like this could be the cause.

G'luck

PS. I think the lack of smoke is a really good sign, as far as the loss of a cylinder thing goes.

[biggz786]

doesn't sound too bad, might just be a small complication

like JK said, test for any leaks, double check on how tight your bolts are, make sure they are torqued properly, and see which code(s) pop up

[1990300zxtt]

It sounds like a big boost leak you probably popped a hose off.

[fuzzymonkey]

possibly a boost leak...does it feel like driving an NA or just like literally towing a house? If just feels slow like a normal car, maybe you're in safety boost?

[mike300zxt]

Make sure all your intake piping from air filters to turbos to intercoolers to throttle bodies is air tight.

Make sure your CAS is tightened down, and dead on 15 degrees BTDC.

Make sure you have proper fuel pressure at idle.

[Jakiro]

I just got around to checking it out today, pulled the ECU codes (55), and did a cold compression check - outlook not good.

#1- 150 psi
#2- 60 psi
#3- 150 psi
#4- 90 psi
#5- 150 psi
#6- 60 psi

I'm not sure what I'm going to do with it at this point, but i can tell you I'm not selling it...

At this point, I'm almost wondering if I blew the headgasket on the driver's side (OEM HG).... Only thing is I didn't see anything coming out of the exhaust, and I haven't checked the fluids for mixing.

[elcid]

You know, I am not a mechanic , so take it as a grain of salt. Looking on how you got 3 low compression numbers on 3 cylinders.... sounds like a head gasket for sure!

[mike300zxt]

Originally Posted by Jakiro

I just got around to checking it out today, pulled the ECU codes (55), and did a cold compression check - outlook not good.

#1- 150 psi
#2- 60 psi
#3- 150 psi
#4- 90 psi
#5- 150 psi
#6- 60 psi

I'm not sure what I'm going to do with it at this point, but i can tell you I'm not selling it...

At this point, I'm almost wondering if I blew the headgasket on the driver's side (OEM HG).... Only thing is I didn't see anything coming out of the exhaust, and I haven't checked the fluids for mixing.

Oh man, that really sucks after all the work you've put in.

Stock head gaskets are pretty bullet proof unless you don't clean or surface the block/heads when you change it, or overheat the engine badly, or don't install the heads to spec with a torque angle guage. I can't see it being blown in all three cylinders.

Are you able to do a leak-down test to determine where your compression loss is?

Have you checked your timing belt tension? Maybe a cam has slipped out of phase enough to cause too much overlap, but not enough to cause interference. I'd be more prone to suspecting that than a head gasket.

[Meatman]

Originally Posted by mike300zxt

Have you checked your timing belt tension? Maybe a cam has slipped out of phase enough to cause too much overlap, but not enough to cause interference. I'd be more prone to suspecting that than a head gasket.

That was my first thought.... but would there be a 30psi diffrence in the 1 cylinder? I would think it would be semi-even across the 3 cylinders.