Need some serious help... emission system !!!!
 

I have a 1970 GMC C1500 pickup... with a emmission system that I can't figure out. The canister has three lines coming out of it. The tank and PCV lines I can handle --- it is the one mark air cleaner I can't sort out. It is connected to a metal tube that appears to bolt to the bottom of the passenger side valve cover... and then it connects somewhere. It appears it once connected to the air horn of the air cleaner... I know everyone thinks I'm crazy... I tried to attached some photos but could not make it to happen.. so I will be happy to email you a copy if it will help understand what I'm talking about. I would like to figure out how this monster once went together.... I think I'm missing a hose and a component that fits into the whole on the bottom of the air cleaner.... \

Check every book I can find in four libraries and no luck... can anyone HELP me...

Thanks



Vic 1970

i'm kinda lost here....the only metal tube i can think of that would be in the vicinity of the valve cover is the heat riser for the choke, or possible the vacuum tube for the vacuum modulator.

here's some pics I resized for vic1970. He can add the explanation tomorrow.

pic 1 - canister

The tube it connects to:

another view of the tube:

bottom of the horn on the air cleaner:

another view of the horn on the air cleaner:

and here's the canister assembly:

Ok, thanks for the pics Scott.....now i'm not so lost. I've never seen one of those systems working, but I think the tube comming from the canister that says "air cleaner" is supposed to run to a nipple on the breather snorkel which is apparently broke off or was a plastic piece that can be replace......

My thinking on this is it is a vent from the canister and it feeds to the air cleaner to draw the vapors and burn them instead of just venting into the air.

Scott, that is an interesting shade of finger nail polish you are wearing!! :p

The only one?
 

Why is it, I get to have the only one in the world...??!!! @%#*

Scott thanks for posting the pictures.

I agree with o'l Buck that the system connects to bottom of the air cleaner... does anyone have a part number? or any idea where I can find one. I have been through all the junk yards in the area with no luck... I think it is an early Calif emission system, even my gas tank is mark "CAL", heck even the carb is different and have not been able to track down anything like it...

Thanks for your help up front...

Vic 1970

LOL, isn't it though? Wish I was working on something that clean, but I just resized and posted the pictures, wasn't actually there.

Scott

OK OK lets get to the issue
 

The finger nail polish is very nice on my daughters hands... and yes they are clean...

BUT what about the tube on the engine... LOL... somebody has got to know... right?

Vic 1970

i just checked my 72 that has a canister, one line tees into the pcv, one line to the tank and the third is hooked to a nipple on the side of the carb under the choke pull off. i'm assuming it's correct routing as it passed calif emissions last time we had to smog it and i have not changed anything since then. your canister is different than mine in appearance, mine has three different size hoses and the one hooked to the side of the carb is pretty small. i hope this helps but it probably makes it more confusing.

Huh??

You never have to smog a '72 in California. Never.

Are you sure you're talking about the same year truck? The emissions systems changed very quickly in the early '70s.

Michael,
re-read my post !!!!!!!!
i know we don't have to smog them now, but there was a time, not too long ago, that we did. we had to smog anything 55 and newer for a while, even though 65 and older never had smog equipment on them. i work in a calif. certified smog shop and have been there for 17 years as a muffler/exhaust person. one thing for you to think about-- the new software we got for our smog machine has everything on it for 66-73s, i doubt they would spend the money to put that information on the updated software if there wasn't plans to use it in the near future.
and FYI--i do know a little about these trucks, i have been in and around them since 1969. in that time i've owned over 200 of them in one form or another.
have a nice day.

Jerry, what do you think the hole in the air cleaner is for? I have looked many and I can find no other air cleaner air horn like it... we have owned the truck (Dad can't remember what was there and he did not drill a hole.

Also, I don't need the tube to run a line to the carb... and I have looked and I can find no connection on the orginal carb or manifold I have.

Tough one but I know that someone out there can tell us....

VIc 1970

I have the same thing in my 72 chevy, i bypassed it, no emissions for trucks and cars 1975 and below here :D

Vic,
i've never seen the hole in the end of the air cleaner. hopefully someone here will be able to help. best of luck.