73-87chevytrucks.com

73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: traumajunkie on February 25, 2015, 09:10:00 AM

Title: Emissions
Post by: traumajunkie on February 25, 2015, 09:10:00 AM
I want to remove the emissions off my 84' 250, half the hoses lead to nothing anyways or are missing completely.. I am not sure what to keep and what to remove
Title: Re: Emissions
Post by: LTZ C20 on February 25, 2015, 09:30:19 AM
Post a few pics of your engine bay
Title: Re: Emissions
Post by: traumajunkie on February 25, 2015, 10:00:32 AM
This is the only 1 I have right now (I circled in red some main ports) I can get more if needed, There is a port for 5 vacuum lines right in front of the thermostats that has ONLY 1 hose going from the far right tracing to the valve connected to the valve on the valve cover and then there is a tube going from the back/top of the valve cover leading to that same valve with a t adapter and a hose leading to nothing
Title: Re: Emissions
Post by: Shifty on February 25, 2015, 10:14:49 AM
Looks like a thermactor on the air filter housing, a.i.r. pump hose, diverter valve, ported vacuum switch on the thermostat housing, pcv valve.  At the very least, I'd hook up the pcv, as it's not really emission equiptment.  The thermactor isn't either, it just closes a valve in the air intake to force hot air from your exhaust manifold when the engine is cold.  The other pieces work in conjunction for emissions.
Title: Re: Emissions
Post by: traumajunkie on February 25, 2015, 10:19:48 AM
what pcv are you referring too..
Title: Re: Emissions
Post by: traumajunkie on February 25, 2015, 10:22:50 AM
the thermactor Is the opening on the bottom of he air filter which goes straight down near the swing arm correct ? That piece was already missing and the opening it goes into leads to nothing except the ground
Title: Re: Emissions
Post by: Shifty on February 25, 2015, 10:39:18 AM
what pcv are you referring too..
The pcv valve is in your highest red circle, it pushes into the valve cover with a rubber grommet.  PCV actually stands for positive crankcase ventilation, and relieves pressure caused by oil and gas vapor, and re-burns it through the engine, and extends the life of gaskets and seals.  The bottom side of your air filter housing inlet should have a (roughly) 1-3/4 hole that a "foil"-like tube that runs to your exhaust manifold that draws only hot air when starting your engine cold.  A lot of those go missing over the years, as the foil-paper tube gets pretty brittle with age.  If you live in warm-weather country, you'll probably have no use for it. 
Title: Re: Emissions
Post by: traumajunkie on February 25, 2015, 10:44:57 AM
Ok so the pcv you said to keep where does the hoses go, obviosuly from the valve cover to the  valve connected to the cover but then there is one more hose that branches off, And If I keep that what else do i eliminate
Title: Re: Emissions
Post by: roger97338 on February 28, 2015, 11:56:45 AM
When General Motors discovered how much cleaner engines ran with Positive Crankcase Ventilation systems, they shared their solution with the other American auto makers, royalty free. Before PCV, engines used a 'road tube,' which vented unburned hydrocarbons, unfiltered in any way, almost directly onto the roadway. They also slobbered a fair amount of oil onto the highways and newly-built freeways.

I have a hard time picturing any company in the current era performing such an altruistic act.
Title: Re: Emissions
Post by: traumajunkie on February 28, 2015, 05:58:05 PM
I appreciate the reply's, after doing some research I found that a bad pcv will cause an oil leak, i have replaced the pcv but can not figure out what it connects to, does it go to the manifold or the carb?? There was a hose on the old one that just sat between the carb and manifold but was not connected. (4.1L inline 6)
Title: Re: Emissions
Post by: Irish_Alley on February 28, 2015, 11:28:19 PM
it goes to manifold vacuum. i dont know why but my cummins just has a vent tube and its a 1987 guess maybe due to the turbo? or they just didnt care
Title: Re: Emissions
Post by: traumajunkie on February 28, 2015, 11:52:37 PM
I have looked, i do not see anything on the manifold or carb, i am contiplating just placing a breather in place of the pcv
Title: Re: Emissions
Post by: traumajunkie on March 02, 2015, 09:12:08 AM
I am running out of patience, I have checked all service manuals and cannot find where the pcv connects to, there is no spot on the carb nor on the manifold. I did find a vacuum line/ leak on the side of the block in between the front and back push rod covers which I cant find any info on either... any more help would be gratefully appreciated
Title: Re: Emissions
Post by: traumajunkie on March 02, 2015, 09:13:45 AM
I also find it confusing that i have a pcv valve in the back and a pcv hose in the front??? :o
Title: Re: Emissions
Post by: roundhouse on March 02, 2015, 10:42:32 AM
One valve cover needs to have a breather filter or be piped back to main air filter housing

And the other needs to have a PCV valve and tube back to intake manifold or carb base

Look close.  Somewhere on the carb base or intake manifold will be a 5/16 or 3/8 nipple for a vacuum line

Or a plug or cap where someone capped it off

Mine runs much better wih it disconnected
I realize that means I have some problem
  But we can't figure out what it is


Sent from my iPhone using Tapatalk
Title: Re: Emissions
Post by: Irish_Alley on March 02, 2015, 11:52:53 AM
sometimes they are directly behind the carb so you cant see them
Title: Re: Emissions
Post by: zieg85 on March 02, 2015, 12:30:53 PM
One valve cover needs to have a breather filter or be piped back to main air filter housing

And the other needs to have a PCV valve and tube back to intake manifold or carb base

Look close.  Somewhere on the carb base or intake manifold will be a 5/16 or 3/8 nipple for a vacuum line

Or a plug or cap where someone capped it off

Mine runs much better wih it disconnected
I realize that means I have some problem
  But we can't figure out what it is


Sent from my iPhone using Tapatalk

Remember this is the 4.1L I-6
Title: Re: Emissions
Post by: roundhouse on March 02, 2015, 01:15:35 PM

One valve cover needs to have a breather filter or be piped back to main air filter housing

And the other needs to have a PCV valve and tube back to intake manifold or carb base

Look close.  Somewhere on the carb base or intake manifold will be a 5/16 or 3/8 nipple for a vacuum line

Or a plug or cap where someone capped it off

Mine runs much better wih it disconnected
I realize that means I have some problem
  But we can't figure out what it is


Sent from my iPhone using Tapatalk

Remember this is the 4.1L I-6
still should have one breather into the crankcase somewhere  and a vacuum line


Sent from my iPhone using Tapatalk
Title: Re: Emissions
Post by: traumajunkie on March 02, 2015, 01:28:42 PM
I have one valve cover, first hole goes to breather, second hole is oil fill and the third is the pvc valve.. I have taken the carb completely off and still no port on the carb,carb base or manifold
Title: Re: Emissions
Post by: roundhouse on March 02, 2015, 05:19:04 PM

I have one valve cover, first hole goes to breather, second hole is oil fill and the third is the pvc valve.. I have taken the carb completely off and still no port on the carb,carb base or manifold
So where does your HVAC controls and other emission controls  like the thermactor draw vacuum from ?



Sent from my iPhone using Tapatalk
Title: Re: Emissions
Post by: traumajunkie on March 02, 2015, 08:28:35 PM
Here is how I ended up doing the pcv, let me know what you guys think. It still seams to idle a little rough though...
Title: Re: Emissions
Post by: traumajunkie on March 02, 2015, 08:29:54 PM
I have no idea what a hvac is, sorry this is my first build ever and still have a lot to learn
Title: Re: Emissions
Post by: LTZ C20 on March 03, 2015, 01:51:20 AM
HVAC: Heating, Ventilation & Air Conditioning

The HVAC term applies to vehicles, houses, building, new farm equipment(enclosed kind), warehouses, basically most anything that has heating AND cooling systems.

The HVAC in a car and often in other places can also be referred to as the Climate Controls.

It's very easy to mention anything with just a heater as the heater, something with heating and cooling the HVAC and anything with only cooling as the AC. If your talking about a heater only vehicle or just the heater system, then it would be the heater. If your talking about some kind of cooling system or just the air conditioning system it self then it would be the AC. If your taking about them together as 1 unit or system then it's HVAC.

Roundhouse asked where your vacuum supply comes from for the HVAC controls, this is because both the heater and air conditioning require a vacuum source to operate curtain parts of the system. They do not have seperate sources of power to make them work.
Title: Re: Emissions
Post by: LTZ C20 on March 03, 2015, 01:53:16 AM
Sorry, information overload there. Just want to make sure that you understand so we can help you better and you expand your knowledge of things mechanical.
Title: Re: Emissions
Post by: traumajunkie on March 03, 2015, 08:36:58 AM
Haha ,Actually was not that bad and it makes since so thank you for explaining it... However I do not have ac, just two heater hoses coming from the firewall to the front of the motor.. So if there is a vacuum line Its in a different location...
Title: Re: Emissions
Post by: LTZ C20 on March 03, 2015, 10:45:36 AM
Ok good. The vacuum line should be going into the cab at a little rubber grommet type deal somewhere above the top of the heater box, I believe directly up above the heater hoses.
Title: Re: Emissions
Post by: traumajunkie on March 03, 2015, 10:58:22 AM
Lol I dont have a box either.. I honestly feel like this poor truck has been through the ringer
Title: Re: Emissions
Post by: zieg85 on March 03, 2015, 12:23:31 PM
Went out in the pour down sleet and snapped this picture.  Without removing the air cleaned for exact port the PCV vacuum comes from it is besides the carb.  This is a 1984 C10 4.1L all factory emission stuff
Title: Re: Emissions
Post by: LTZ C20 on March 03, 2015, 01:22:22 PM
The vacuum line into the cab should be somewhere in the area of the red square. More off to the right where I can't see.
Title: Re: Emissions
Post by: zieg85 on March 03, 2015, 01:32:19 PM
The vacuum line into the cab should be somewhere in the area of the red square. More off to the right where I can't see.

Now I am confused.  I thought the original question was manifold to PCV?  He shouldn't have a vacuum line going into the cab since it is a non-AC situation???\

Am I missing something???
Title: Re: Emissions
Post by: timthescarrd on March 03, 2015, 01:53:16 PM
Older heater only truck didn't use vacuum, it was all cable driven.  PCV should be getting steady vacuum, so if your tying into the breather, it's probably only getting vacuum when the throttle is open (thus rough idle).  Anywhere on the intake manifold or carb that you can find full vacuum (i.e. not ported) should work fine
Title: Re: Emissions
Post by: LTZ C20 on March 03, 2015, 02:28:01 PM
He should still need vacuum to operate the floor or defrost vent positions right? Unless in a heater only truck these are cable operated, if that's the case then ignore everything I said about there being a line into the cab and I'll pull my foot out of my mouth.

Now I think I'm missing something, I have an ac truck so I have no idea lol.
Title: Re: Emissions
Post by: LTZ C20 on March 03, 2015, 02:29:11 PM
And timthescarrd comment was on page 4, which I just now saw. Cable driven system, I'm done here haha.
Title: Re: Emissions
Post by: zieg85 on March 03, 2015, 02:35:29 PM
He should still need vacuum to operate the floor or defrost vent positions right? Unless in a heater only truck these are cable operated, if that's the case then ignore everything I said about there being a line into the cab and I'll pull my foot out of my mouth.

Now I think I'm missing something, I have an ac truck so I have no idea lol.

Everything is cable operated on a non-AC truck...
Title: Re: Emissions
Post by: traumajunkie on March 03, 2015, 08:36:45 PM
Went out in the pour down sleet and snapped this picture.  Without removing the air cleaned for exact port the PCV vacuum comes from it is besides the carb.  This is a 1984 C10 4.1L all factory emission stuff
I appreciate that, are you referring to the brass hose going into the black rubber hose in the bottom left ? I will get a better picture tomorrow when i get home of the carb and between it and the manifold. I have looked and looked and cannot find anything. After reading tese post I am starting to think I am crazy. a comment was made from the rough idle being due to me connecting it to the breather..will this position work minus the rough idle or is it pointless?
Title: Re: Emissions
Post by: zieg85 on March 03, 2015, 09:35:42 PM
this one.  Next available time weather permitting I will take off the air cleaner.
Title: Re: Emissions
Post by: traumajunkie on March 03, 2015, 09:40:26 PM
Yea thats the one i was talking about, so the black hose goes into the carb
Title: Re: Emissions
Post by: zieg85 on March 03, 2015, 09:48:48 PM
Yea thats the one i was talking about, so the black hose goes into the carb

I will check on mine but if yours does at the base of the carb that should be manifold vacuum.  If you have a rough idle you may have a vacuum leak or carb is shot or out of adjustment.  Mine runs perfect, I just have a knock, really uses oil and antifreeze in the oil.
Title: Re: Emissions
Post by: LTZ C20 on March 03, 2015, 11:25:38 PM
I'm an idiot today.
Title: Re: Emissions
Post by: traumajunkie on March 04, 2015, 05:50:34 PM
here is some pics, idle is about 700-800 and when i gas it it sputters so may just need a carb clean ( have not done it yet) tell me hwat you guys think
Title: Re: Emissions
Post by: traumajunkie on March 04, 2015, 05:53:05 PM
pic 1
Title: Re: Emissions
Post by: traumajunkie on March 04, 2015, 05:54:43 PM
2
Title: Re: Emissions
Post by: zieg85 on March 04, 2015, 06:06:52 PM
What is this?
Title: Re: Emissions
Post by: traumajunkie on March 04, 2015, 06:29:19 PM
something broken, I initially thought that was the port but it has no suction nor does it blow
Title: Re: Emissions
Post by: zieg85 on March 04, 2015, 06:39:38 PM
something broken, I initially thought that was the port but it has no suction nor does it blow

Spray some brake clean down there and see if it effects the idle.  That may be where the PCV line went, got broken and plugged...  That may be the source of a vacuum leak if the RPM's increase.

I will take my air cleaner off next good day and take a look at mine for you.
Title: Re: Emissions
Post by: traumajunkie on March 04, 2015, 06:42:38 PM
10-4 I will do it tomorrow, Thanks again for your help
Title: Re: Emissions
Post by: Irish_Alley on March 04, 2015, 10:40:44 PM
it may also be a ported vacuum