Hey guys, recently i notices my car idled kind of rough. My Boost gauge shows 16 and 17mmHg at idle (wich to my knowledge is low because it should be 19 - 20) so i went ahead and did a boost leak test, this is where things get interesting. I tied all the clamps that needed to be tightened. but i still heard a hissing noise and the car won't hold 3psi for more than maby 3 seconds. my friend pushed in the Dip stick and walah! no more hissing went up to abt 4 psi he let it go and well it leaked all out.

First thing i thought was "PCV valves are bad!" so I tore her down started taking her appart and then i see that the PCV hoses are new... and so are the valves. I cleaned em put the valves back on and I did a boost leak test again but this time with the valves hooked up and no hoses on them to see if and wich one leaked..... none of the PCV hoses leak. the Boost leak is coming from the hoses that attach to the valve cover. I take off the oil filler cap and sure enough the air comes out through there too.

My Mods are as follows.
NO AIV's
Carbon Canister delete
Apexi Intake
Apexi Boost gauge
Stillen 2.5" Catback exhaust.


1991 Twin Turbo. 163K on the clock.



Edit: Ok i see that the intake valve covers are attached to the turbo inlets (duh) so that's why im getting the air leak through there. I should go ahead and replace the PCV valves right?

PCV's are cheap, so it can't hurt too badly to replace them just in case. But I don't suspect they are the root of your problem.

What work has been done to the car lately?

And have you beaten on the car lately?

Do you keep up with oil changes?

K changed the PCV valves, and put on new hoses, also got a new dipstick tube. now the only thing leaking is my IAC time to fix that. `

Edit: car was always maintained @ the dealership. 120K mile maintenance was done in 04
Haven't really been driving the car arround so no havent beat on it lately.
and I am religious about oil changes 4 quarts of Royal Purple 10W-30 + OEM Nissan Filter

10w 30 is pretty light on these cars. It's likely not the cause of your problem, but you really should go with a thicker oil.

... wait a sec... your idle air control valve is leaking and you didn't mention that in the initial post?? lol That's why the engine isn't running the vacuum that it should and also probably why it's running rough.

As for shooting the dipstick out, that could've been a handful of different non-critical, non-related things.

lol yeah the dipstick was worn not sealing thats why it would come off, the new one stays in there nicely. and i didn;t figure out my IAC was leaking till i was done with tightening down clamps and vac lines that where leaking. that seems like its the last thing leaking. let's hope so!

Looks like I'll be doing a plenum pull...... I used RVT on the IAC valve. I'm going to try it again. if not plenum pull it is. god damnit.


Edit: Might go through and just refreshen up the engine. with all new gaskets, belts, and seals.

Why are you complaining about a plenum pull? Did you not eliminate the EGR and do the coolant bypass? My plenum pulls take 15-20 minutes with no hassle at all...

nop not yet, i bought the car bone stock, only had the car for about 3 months now. so it still has EGR and all the gay hoses under the plenum. if it's not my IAC that was leaking because i didn't let the RTV dry enough. (i took it off and cleaned it again reaplied RTV gasket sealer) if it still has vac leak tomorrow. Im just going to go ahead and order a Nissan Gasket kit, ARP head bolts, and EGR delete kit, it'll also be a good time to fix my clutch dampener system. (frigging leaking somewhere had to cap it off clutch is stiff as hell)

if tomorrow still leaks I'm just goint to refreshen up the Engine with new gaskets, Seals, Vacuum lines, and all those cool little things that like to break over age.