i need to know where this vac line goes. it is one of the metal ones that runs in front of the motor... in the pic it is the one closest to the radiator and front of truck. on the exhaust side of the truck it runs to the charcoal canister... but on the intake side i have no rubber. as of now it simply is open at the metal portion... no hose at all on the intake side. can someone give me a pic of where the hose goes from here?

i was messing around deleting hoses and stuff and lost track

here is a pic i got off ratsun of the three metal hoses... it is not my truck but is set up the same... like i said... of the three metal hoses (bottom right of photo) it is the one running closest to the front of the truck and i need to know where the rubber vac hose goes on the intake side

Looks like the outside(closest to radiator) hardline goes to the charcoal canister and the other side goes to the outer part of the ab valve.

I just noticed a t connecter in mine but it shouldn't branch of to anything according to the vacuum diagram.

ok so maybe its not as easy as i thought... my ab valve is fully sealed

there are only 3 places it can go and only 2 that i think it would go

*1. to the e.g.r control solenoid valve*2. one of the hookups on the carb itself3. the air cleaner assembly

any ideas guys?

of my 3 hoses... theres the one running to the distributor from the carb... theres the one running to the canister from the ab valve... then there's this one... it also runs to the canister but i don't know from where.

i don't know if your guys' canister has the labels for the hoses or not... but if they do its the one labeled 'dist vc'

I will be going to town on the 720 today(i work til like 3). We will figure out the vacuum lines.

Also I will scan in my Vacuum diagrams later so they will be up on here.

well i have the book of diagrams and it only talks about the other two hoses... it says nothing of the third...

I wish I brought my manual to work with me.

What year motor? 84-86 carb'd?

nm i see 1985. I ask only because the early 80's carb is way a different vacuum diagram. Probably due to an older carb and no emissions like ours.

you can t tap that one off the vac hose for the distributor advance. . . this is what i did when i removed the a/b valve according to the diagrams the hose needs to signal only when above idle (hence why i taped the dist vac line) so that it can opent he canister and evacuate the fuel vapors into the larger hose on the intake manifold. this is very important to have, you should have vac in the fuel tank not pressure so when you take the gas cap off it sucks not blows

so what does it do then? reduce pressure in the tank? cause there are more hoses going to and from the canister and tank and i figured those would cover it... i just drove it around with the metal part capped off and it ran fine but i didn't get on it hard or anything

PEZi720 wrote:so what does it do then? reduce pressure in the tank? cause there are more hoses going to and from the canister and tank and i figured those would cover it... i just drove it around with the metal part capped off and it ran fine but i didn't get on it hard or anything

it opens the apature to purge the fuel vapors from the tank. not sure what the other small line is for (ill look when i get home since its all taken apart.) the large line is the actual purge line which draws the fuel vapor through the charcoal canister and into the engine to burn the vapors.

yeah the small line is the one i need to know about... i left the large one on

on mine the little hardline closest to the motor connects to a nozzle bottom left side of carb toward the front

yep, t tap it from the distributor vac line. I re-read my notes from tracing all the vac lines and it was based off the signal line for the distributor anyway, just branched off the ab valve (which was also signaled by the vac for dist)

breadbox wrote:on mine the little hardline closest to the motor connects to a nozzle bottom left side of carb toward the front

so that means it would be the same one as the distributor advance so it would need a t tap like 2kredz3 has said? just confirming...

i drove it again to go get gas and take some stuff to checker and it ran excellent... i was afraid to push it hard because of the vac line and the hole on the headers where my EGR was is now ghetto rigged shut... everything worked great tho so i pushed it down pretty hard and everything went great! i may leave it as is unless something goes weird with it

well you have seen pics of my engine, i have no emission crap on it at all. In my opinion you need to make sure you have the carbon canister hooked up to make sure you dont get to much pressure in the tank (remember there is no stock fuel pressure regulator on these trucks so you can end up with too much fuel pressure which will mess up the carb)

so dont think of it like an emissions thing

i also posted this question in my new build thread... but do you think it is possible to delete the charcoal canister of i put a breather filter on the tube to the gas tank instead of the canister?

You can delete it all you want, the main thing it does is vent gas fumes from the tank.

well that's the thing... it prevents vapor lock so i would need to make sure it can still do that right?

k&n makes a little baby breather filter (.25" i.d.) that i could clamp around the tube to the tank under the firewall.... think this will do the trick?

sure, but you might ask in a motorsports forum what they do to vent fumes in race applications.

ON my 240sx the tube dumps out at the fire wall.

that's where mine would be... stock the tube comes up to the firewall then has a rubber connector to the piece that stretches to the piece that runs to the canister. so delete it all... and put a breather on the tube at the firewall is what i'll probably do

PEZi720 wrote:that's where mine would be... stock the tube comes up to the firewall then has a rubber connector to the piece that stretches to the piece that runs to the canister. so delete it all... and put a breather on the tube at the firewall is what i'll probably do

Did the breather work ok??i had a firebird that had a vac problem and the canister wouldnt purge at all..every time i opened the cap it would his for a few seconds lettin the pressure out so i just pulled the line into the can and it didnt go it anymore..isnt just having it vented enough??

yep.... breather is working great

awsome!!and thanks for the pics of under the hood they helped alot with gettin rid of all the vac lines!!made it run alot better gettin rid of all the old crusty lines!

[QUOTE=PEZi720]

so that means it would be the same one as the distributor advance so it would need a t tap like 2kredz3 has said? just confirming...

i drove it again to go get gas and take some stuff to checker and it ran excellent... i was afraid to push it hard because of the vac line and the hole on the headers where my EGR was is now ghetto rigged shut

What are you using to cap the holes in the exhaust manifold?

i only have one vac line... the distributor advance... there is no t-tap on mine... just the distributor advance and nothin else...

i used a pipe fitting to plug the EGR on the exhaust side

hey pezi you got a pic of your breather on the gas tank line??or a link to a site were i can find one??

don't have one but i can take one and post it up tomorrow...

the part is a k&n filter #RU-5162

dang thats i little sucker aint it!!didnt even know they made airfilters this small..i used to run nitro rc cars and even the nicer ones just had a piece of faom stuffed over the end of the carb!wish i had a k&n on my buggy would have been sweet but im defently pickin one up for my truck!