Charcoal filter

Hi guys new on here but this site was highly recommended for tech info and problem solving
I've got a charcoal filter that appears to be leaking boost from the bottom of the unit
It's not cracked it just has a pipe that runs out to atmosphere under the car and it appears to be sucking in large quantities of air not sure if it's a faulty unit or not if it is could somebody advise how I can safely disconnect it
Any help would be much appreciated
Cheers Tom

The idea of the charcoal filter is to collect fuel vapours, it will have a pipe that goes to atmosphere with a one way valve in it. It shouldn't be connected to the boost side at all mate, i would get a vacuum pipe diagram and compare it to your car as it's possible that they are mixed up, iirc there is a diagram on here somewhere, if not there defo is in the net.

Sorry for my terminology I ment to say vacuum it was sucking in air not blowing it out does anybody have a pic of theirs or any instruction on taking it off I've only had this car a week and it runs like shit every time I find a leak and get it running good it makes another one lol

Hopefully these will help you mate.

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Perfect cheers for that buddy just what I needed

Welcome to the forum ..... what boost set up do you have more info on your car  set up please maybe some pics of your engine bay so we can see your pipe runs  so we can help you  

Well it has a turbosmart electronic boost controller but I've bypassed it with a manual screw type because I had no idea how to programme it lol
It's a fully forged engine running about 1.4 bar of boost
The characteristics of the engine change on a daily basis I keep finding vacuum leaks sealing them up it runs great for an hour or so then goes back to running rich and Idleing very lumpy it does have high cams but they wouldn't make it run this badly it misses and pops now
I've capped off the charcoal filter and every hose going to it (not sure if this was the right decision but I'm desperate now lol)
I've replaced the maf sensor still no joy here are some pics

Mine is plumbed slightly different to stock but i think this is basicly right and should give you a rough idea...


Remove charcoal canister and block this pipe...

See the pipe with the screw in at top left of pic nexted to the tissue.

I think it used to go to the small pipe on top of the charcoal canister and cant be used for a proper vacuum source due to its location on the throttle bodies so is best off blocked.



Then you are left with these 2 other locations the charcoal canister used to connect to,one chassis leg and the other down by the fuel pipes,these are simply joined together so it breaths into the chassis leg,do not block the one by the fuel pipes.
Cant 100% remember where this comes from but think it could be the fuel tank vent or something.



Then you are left with 3 good vacuum sources from the black vacuum box on the back of the manifold



The top thin one I have running to the fuel pressure regulator only,it is not recommened to T into this line as if this leaks you will run lean and be in alsorts of trouble.

The next thicker 2 are more personal preference but I have the middle one T-ed down and going to the avc-r map sensor and also the stock boost gauge map sensor on passenger inner wing, which I believe can be removed if unwanted as its only for the incar gauge I think.

Bottom hose is T-ed down again and go's to an incar mechanical boost gauge and also to the dump valve.




Avc-r boost controller solenoid is plumbed of the stock location on the manifold and then from solenoid to actuator on turbo.


Well I think that's basicly right but its always worth double checking.

Thanks for the help seems to be running much better now
Still running rich though I think it might be reading an incorrect intake temp not sure where the iat sensor is on thease but last time I went to a mapping place they said it was reading 170 degrees which is obviously mad it's running a 300zx maf sensor not sure if the iat is incorporated in that or if it's in the intake piping any ideas anybody?

are you tom by any chance?

if so as said tom the z32 as far as im aware has no facilities to log iat all it does is monitor air flow and sends the reading to ecu

unless theres an aftermarket inlet air temp sensor fitted the only other temp sensor is an ambient one which is fitted near front slam panel.

if you want il plug a commander into the pfc to see what this reading actually is as I believe the guys you took the car to really have not got a clue lol

Yea it is me bob I forgot our convo if I'm honest it's running great again now looks like it just needed a proper thrashing to clear it out after all the other running problems problems I'm gonna stick the new swirl pot and the afr sensor in and I'll be taking it to be mapped
Cheers for all your help by the way great having a specialist round the corner from me
I also found out that if a vehicle doesn't have an iat it registers huge temps anyways so that explains it nicely

yep as said tom the guys you took it to haven't told you the full facts.

offers there though if you want me to plug a commander in to check on whats what, it wont take more than 15 minutes to do

oh and don't bin that old z32 as il buy it from you or sort you out with a few bits as ive got someone coming over from Ireland next week who needs one as were building his engine at the mo

Yea cool I'll pop in tomorrow n we can plug it in
Yea I've got it at home I'll bring it in

ok cheers tom
il sort you out with a proper water separator too before you take it up there rather than the loop pipe.
if you can pop up in the afternoon as il have a bit more time then

Perfect see u then mate

gtirx2 by plumbing the avcr map sencor & your mechanical boost gauge into the middle & bottom ports on the vacuem box behind inlet, would you not get inaccurate boost readings? As the bottom 2 ports are bigger bore diamiter than the top port on the vacuem box.

So basicly your getting a flow of vacuem sucking from a bigger port on vacuem box going in to a smaller port on avcr map sencor & mechanical boost gauge if that makes sence?

Nissan obviously made the middle & bottom ports a bigger diameter than the top port for a reason? Maybe to create more vacuem?

Im only asking because I may remove my c/c & set it up the same as you have, BUT don't want inaccurate boost readings if you know what I mean... AVCR is a pain in the arse to set up as it is  

I'll be honest none of that made sense to me lol I have little knowledge on turbos all I got from that is that I might be getting false boost readings soo let me know if u find out I've done something wrong lol

Hhmm now you have got me thinking lol

I will have another look into it but I am pretty sure the size of the line should not make any difference, and if it did it would proberly be very minimal indeed and nothing to worry about.

If maybe they were plumbed from different locations on the manifold you might get a small difference, but all coming from the same place they should all be pretty much exactly the same.
I think in theory you could take a vacuum/pressure source anywhere after the throttle body/s with any size hose and the readings should always be the same?

Hmmm maybe, If you have a look into it & let me know please matey id be gratefull Just don't want to remove it all if this is the case :/

yes the only one that should differ would be the one to boost gauge sensor which tees off to the fpr (should be no other items such as dv etc running from that) other than an aftermarket boost gauge which will work fine

the main port on rh side of throttle body should run the boost controller to actuator as it does on a stock pulsar with stock boost solenoid

Im meaning the bottom 2 ports on the vac box Bob. there a bigger diameter than the top port that gos to FPR & standard boost selonoid on inner wing!

So because there a bigger diameter port would you get false readings from plumbing a aftermarket boost gauge & the little round AVCR selonoid in to them?

Because the middle & bottom port on the vac box is about 7mm bore & hose fittings on a boost gauge & AVCR selonoid are a 4mm fitting

The way I see it is that all of them ports on the vacuum box do the same thing and you could plumb them to any of the mentioned ancillaries and they would all function as normal.

I think it maybe slightly different on the gtir because of the quad throttle bodies and its best to take a vacuum source from after the throttle bodies collectively instead of just the one,but I think this is what the vacuum box is doing on the back of the manifold anyhow.
On a regular single throttle body car any where after the tb should be fine for a reliable vacuum source and read the same,where as the gtir has quads there could be a slight variation between them so that's why there better linked.


I do sort of see what your saying with the larger line and I don't know the exact reason for it but you can get unstable readiings sometimes on some devices.
This is normally pre built into the device though to take care of so should not be a problem.

You may have notice the tiny hole in the original boost gauge map sensor nipple or even some after market boost gauges have a large line but tiny restricted hole in the nipple on the back of them,this is to give a more stable reading I think as without the restictor the gauge may twitch/jump about,think it maybe to dampen the pulses in the line or some thing?

Anyhow I don't think the line size will affect the accuracy or max/min readings just possibly the stability, and as above this is normally taken care of or built into the device in question.

I have not noticed any of these problems with the avcr or boost gauge and they give a perfectly stable reading plumbed in how they are,you have to step the pipe down to fit the avcr map sensor nipple anyhow not that it should make any difference.

The avcr solenoid is as above from bob,this line don't need to be a vacuum source that's why its pre throttle bodies and mostly only sees boost.
The solenoid can be plumbed in any where from the above port to the turbo compressor cover,i believe the closer to the comp cover the more responsive the boost control should be but there are pros and cons to both ways I think.

The one you want to watch or not to use is the one in my first pic as I think this is known as a ported vacuum source (what ever that is lol),I tried it on my bov once and it did not work as it has a very weak vacuum.
I think this one sits right in the middle under a throttle body and is neither one side or the other and depends where the throttle is,think its possible pre tb shut and post tb open,either way I don't think its good for anything other than the charcoal canister.

I am no expert though but the above is how I think it works and has been/was fine for me when it was running.

Ok doke, then that puts a positive answer to it all then lol. Ill give it a go & hopefully it will be all good

I hope it works mate but like I say I have not had any troubles and am pretty certain its correct,i did put a disclamer in on the end of the post though just incase its wrong   

You may also want to consider running them little filters like that come with the hks evc boost controllers in line to the avcr solenoid and map sensor for a bit of extra protection,especially if you are still running a recirculated breather setup?