Still working on it as I type this in search of aid from you guys.

Post plenum install I go to turn on the vehicle and immediately upon startup the idle is extremely low and motor shuts off after roughly 4-6 secs. During those few seconds that the motor does stay on I hear very obvious hissing (most likely vac leaking) from plenum and it's extremely difficult to pinpoint exactly where it's coming from.

I've used RTV applied atop the oem gasket and have tightened bolts at 120 inch lbs. I've checked the MAF and made sure all vac hoses were in. Only hoses that aren't plugged in anywhere are 2 that have coolant coming out of them (there are no remaining holes or anything on the plenum for them to go). So those 2 are corked for now.

If there's anythig that someone has maybe had the same problem or run into something similar please share as I'm all ears at the moment and open to any suggestions.

Thanks,
teeterz

 

Check to make sure the rubber oil fill ring isn't stuck in between the upper and lower plenum.

Also, if you can keep the car idling, run your hand along the circumference of the sealing surfaces. If you hear a change in sound as your hand passes over a particular area, you found the location of your leak.

Loud leaks like that are usually large so it shouldn't be hard to find.

Another thing to try is to spray carburator cleaner around the circumference of the sealing surfaces. When you spray at the leak area, the idle will suddenly jump.
...and you will know where the leak is.

The problem with using silicone is significant though. Silicone won't necessarily hurt the engine but its definitely not good for catalytic converters or O2 sensors. If you have to take the plenum off its going to be a mess and then you need to be extra careful to not let any get into the engine.

 

Ok i did try to find the leak with brake cleaner (same method), and i'm even more confused now...

The plenum is COMPLETELY sealed, i made sure of it, the bolts were torqued perfectly and sealant was flawlessly put into place, and now after i once again started the car and heard hissing once more time i sprayed brake cleaner to try and find the leak.

As i sprayed through this one particular area, the idle indeed jumped up back to normal then went back to rough. So bam there it is i found it..the area would be underneath the BOTTOM collector. Which is leading me to Nissan this morning to go get that particular intake manifold gasket.

click below


I'm just curious how when the only thing that was changed was the UPPER plenum and the underside is being affected?

Thanks,
teeterz

 

it's a kinetix plenum. nothing more needs to be said about that. those have been known to be crap (cheap plastic cracks) anyway so it is probably not your gasket. check the bottom of the plenum itself for any obvious damage or not being even (an uneven surface will not allow it to mate properly)

 

Once again how does your theory work? Since he installed the plastic plenum (that works great ) the lower gasket got messed up because of it. Brilliant

 

FINALLY!
Problem solved..i knew it had to be something overseen or simple. ok this is what was going on and i've illustrated it further below.

The leak (HUGE leak) was coming from underneath the lower collector. The reason for this was because on the OEM Plenum (top) there are 6 places where bolts go in to further bolt down the top. Four of these six bolts (illustrated below) follow all the way through the lower collector and help to fasten the gasket on the lower collector.



Those 4 holes in the lower collector (through which these bolts penetrate) go all the way through the collector and open up underneath...

therefore once installed the NEW plenum (no bolts on top) those 4 holes on those flaps of the gasket were completely open so all the air was escaping through those holes. (that's why when i sprayed cleaner underneath the plenum it would jump idle)



What i ended up having to do is find the same threading of bolts but just shorter, that way there's SOMETHING to occupy those 4 holes and hold down those flaps of the gasket.

Once i figured this out i was curious as to how others that purchase the kinetix plenums go about this issue...are there bolts that come with their kit to put there or what? i bought mine used.

oh and i see that all 6 bolts are implemented onto the lower collector but i believe the center 2 holes on the golden piece don't actually go all the way through the bottom seeing as how i left those out and i'm currently getting no leaks anyways.

 

Yes all the proper bolts come with the kit, and the instructions tell you exactly how to install the plenum

 

any noticeable performance gains?

 

Hey are u the guy with the all blacked out z i saw at the meet the other night!!