Jump to content
SAU Community

Recommended Posts

Hey guys,

I got my stock plenum polished up and when I put it back on again ( new gaskets ) I got this hissing noise coming from around the plenum when the throttle is open up.

Its definetely not a vacuum leak because the car is idling perfectly normal and its boosting fine

Any help would be greatly appreciated :P

Thanks

It can still be a vacuum leak, just a small one. You can try pressure test your intake manifold by blocking the pipe where it comes from the turbo's and then pumping up the intake manifold. If there is a leak it wlll be audiable at 2-3psi.

If everything is good you should be able to pump it up to 15psi and it should hold that pressure. Just be sure your plug doesnt blow out of the intake plumbing or it could launch quite a distance and cause some damage or injury.

what about the auxilary air control? was that taken off when polished? not sure how 34's go... but in 33's it is at the back of plenum (towards the firewall) and it lets in a small amount of air when idle (so the car doesnt stall when the throttle is closed) via a screw.... maybe you can just hear that because its clean now? or whats the condition of the gasket of it?

Its kinda hard to explain the problem so I will describe it the best I can

The hissing noise just appears when the throttles just open up , so if I hold the throttles open in any rpm it will NOT make the hissing noise

It sounds like "pssst" then goes away after that

The car is idling fine and boosting fine.

naut : The car is an R34 GTR its only running the factory boost sensor on the screen , you reckon I should check the vacuum hose ?

WYTSKY : I did taken out the AAC valve and put it back on with NEW gasket and I did NOT fiddle with the screw that controls the idle

Any more ideas / input ?? Im confused now :banana:

Thanks boys

By having the noise go away when you open the throttles it is confirming that it is a vacuum side leak. Meaning the leak is between the throttles and the cylinder head.

3 possabilities...

1. The gasket you relaced under the AAC valve.

2. Throttle shaft seals

3. throttle gaskets

Pressure test it and it will tell you which one it is.

VSPEC R33 : I have replaced all the six individual throttle gaskets , I did MAKE my own gasket for the AAC from gasket paper I have lying around

and which one is the Throttle Shaft seals ?

Thanks

Okay so I took the car to 2 garages and all of them sprayed brake kleen on the plenum + AAC and they couldnt seem to find any leak at all

ALTHOUGH the car is idling higher than before , its just above 1k rpm on idle

Anymore thoughts guys ??

Pressure test. Trust me you wont regret it. Youd be amased at how you can find the smallest leaks so easily, and as a reward your boost response will be better than you ever thought possible when its fixed.

tulalit where are you located mate???

QLD????

If so we have a span on gas machine that we can check of air leak's, vacuum leak's and boost, takes two Min's to hook up, or go to a shop that has one in your area.

Hey guys thanks for the replies :D

EFI Performance : I live in New Zealand , so I will take the car to ST Hitec on friday and see what he says ;)

Meanwhile I will replace the AAC gasket again see if it changes anything :)

Any feedbacks will be much appreciated :)

Since some of you mentioned the PCV valve, it occurred to me to mention the one way valve that is on the clutch vacuum booster. Ive seen them fail and then once the diaphram fails in the clutch booster it will actuall suck air from the clutch booster leak which will increase the idle speed.

Usually you can hear the leak inside the car if you just operate the clutch pedal when the car is idling. Its pitch will change as the diaphram moves.

Well I took the car to ST Hitec and he said I shouldnt worry about it and just leave it and he couldnt find any leak whatsoever

I might rip the plenum off one more time to replace it with metal gaskets this time

Thanks boys :)

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • From there, it is really just test and assemble. Plug the adapter cables from the unit into the back of the screen, then the other side to the car harness. Don't forget all the other plugs too! Run the cables behind the unit and screw it back into place (4 screws) and you should now have 3 cables to run from the top screen to the android unit. I ran them along the DS of the other AV units in the gap between their backets and the console, and used some corrugated tubing on the sharp edges of the bracket so the wires were safe. Plug the centre console and lower screen in temporarily and turn the car to ACC, the AV should fire up as normal. Hold the back button for 3 sec and Android should appear on the top screen. You need to set the input to Aux for audio (more on that later). I put the unit under the AC duct in the centre console, with the wifi antenna on top of the AC duct near the shifter, the bluetooth antenna on the AC duct under the centre console The GPS unit on top of the DS to AC duct; they all seem to work OK there are are out of the way. Neat cable routing is a pain. For the drive recorder I mounted it near the rear view mirror and run the cable in the headlining, across the a pillar and then down the inside of the a pillar seal to the DS lower dash. From there it goes across and to one USB input for the unit. The second USB input is attached to the ECUtec OBD dongle and the 3rd goes to the USB bulkhead connected I added in the centre console. This is how the centre console looks "tidied" up Note I didn't install the provided speaker, didn't use the 2.5mm IPod in line or the piggyback loom for the Ipod or change any DIP switches; they seem to only be required if you need to use the Ipod input rather than the AUX input. That's it, install done, I'll follow up with a separate post on how the unit works, but in summary it retains all factory functions and inputs (so I still use my phone to the car for calls), reverse still works like factory etc.
    • Place the new daughterboard in the case and mount it using the 3 small black rivets provided, and reconnect the 3 factory ribbon cables to the new board Then, use the 3 piggyback cables from the daughterboard into the factory board on top (there are stand offs in the case to keep them apart. and remember to reconnect the antenna and rear cover fan wires. 1 screw to hold the motherboard in place. Before closing the case, make a hole in the sticker covering a hole in the case and run the cable for the android unit into the plug there. The video forgot this step, so did I, so will you probably. Then redo the 4 screws on back, 2 each top and bottom, 3 each side and put the 2 brackets back on.....all ready to go and not that tricky really.      
    • Onto the android unit. You need to remove the top screen because there is a daughterboard to put inside the case. Each side vent pops out from clips; start at the bottom and carefully remove upwards (use a trim remover tool to avoid breaking anything). Then the lower screen and controls come out, 4 screws, a couple of clips (including 3 flimsy ones at the top) and 3 plugs on the rear. Then the upper screen, 4 screws and a bunch of plugs and she is out. From there, remove the mounting brackets (2 screws each), 4 screws on the rear, 2 screws top and bottom and 3 screws holding in the small plates on each side. When you remove the back cover (tight fit), watch out for the power cable for the fan, I removed it so I could put the back aside. The mainboard is held in by 1 screw in the middle, 1 aerial at the top and 3 ribbon cables. If you've ever done any laptop stuff the ribbon cables are OK to work with, just pop up the retainer and they slide out. If you are not familiar just grab a 12 year old from an iphone factory, they will know how it works The case should now look like this:
    • Switching the console was tricky. First there were 6 screws to remove, and also the little adapter loom and its screws had to come out. Also don't forget to remove the 2 screws holding the central locking receiver. Then there are 4 clips on either side....these were very tight in this case and needed careful persuading with a long flat screw driver....some force required but not enough to break them...this was probably the fiddliest part of the whole job. In my case I needed both the wiring loom and the central locking receiver module to swap across to the new one. That was it for the console, so "assembly is the reverse of disassembly"
    • But first....while I was there, I also swapped across the centre console box for the other style where the AV inputs don't intrude into the (very limited !) space.  Part# was 96926-4GA0A, 284H3-4GA0B, 284H3-4GA0A. (I've already swapped the top 12v socket for a USB bulkhead in this pic, it fit the hole without modification:) Comparison of the 2: Basically to do the console you need to remove the DS and PS side console trim (they slide up and back, held in by clips only) Then remove the back half of the console top trim with the cupholders, pops up, all clips again but be careful at the front as it is pretty flimsy. Then slide the shifter boot down, remove the spring clip, loose it forever somewhere in the car the pull the shift knob off. Remove the tiny plastic piece on DS near "P" and use something thin and long (most screwdrivers won't fit) to push down the interlock and put the shifter down in D for space. There is one screw at the front, then the shifter surround and ashtray lift up. There are 3 or 4 plugs underneath and it is off. Next is the rear cover of the centre console; you need to open the console lid, pop off the trim covering the lid hinge and undo the 2rd screw from the driver's side (the rest all need to come out later so you can do them all now and remove the lid) Then the rear cover unclips (6 clips), start at the top with a trim tool pulling backwards. Once it is off there are 2 screws facing rearwards to remove (need a short phillips for these) and you are done with the rear of the console. There are 4 plugs at the A/V box to unclip Then there are 2 screws at the front of the console, and 2 clips (pull up and back) and the console will come out.
×
×
  • Create New...