Emissions System Altered?

[djurs]

Emission system altered? While poking around looking for vacuum leaks I found something that caught me offguard. The Charcoal canister has an open port with no line going to it. I read up on this and one line is supposed to go to the fuel tank (that's still there), and the other goes to the intake manifold, the idea is to get rid of fumes in the tank when the vehicle is started. The spot on the intake manifold (little multiway connector) where I believe the other line is supposed to go has a little nipple on it to plug it off. So there should be no leak, but will my truck run the same without this bit of emissions apparatus, or should I get some vacuum line and hook it back up?

Bearing in mind that I have had some idle issues both at high RPM and with A/C on, that act like vacuum leaks.

 

[IMenriched]

Was the port on the intake pluged/capped? that the line to the carcole canister connects to?

 

[Wicked_Sludge]

i wouldnt hook the canister back up. its hard to tell how long its been un-hooked and what kind of moisture and debris have collected inside the canister since it was unhooked.

if you do hook it back up, you need to locate and plug in the canister purge solenoid and install it inline in the vacuum line that you connect to the canister (the canister does not receive vacuum at all times, its computer controlled).

as long as the vacuum source that used to go to the canister is capped off, having the canister unplugged will not cause any driveability problems.

 

[holyford86]

Don't know about the later 2.9s but the charcoal canister on my 86 is connected to a port on the bottom of the throttle body, there is no purge solenoid on my 86 either.

 

[Wicked_Sludge]

hmm, maybe check your vacuum diagram...perhaps it was removed at some point?

its possible that earlier trucks didnt use one, but im almost positive that they did.

 

[Hahnsb2]

My carbon canister has a line that runs directly from it to the bottom of the throttle body...

 

[djurs]

Okay, can someone tell me where the line is supposed to go on an 89? Where I "THINK" it went was one of the ports on the same vacuum splitter as the brake booster line, which is capped off with a nipple. I don't see a solenoid hanging anywhere. If it's on some obscure spot on the bottom of the intake manifold I may be missing it..

I still feel a little weird about leaving the gas tank vented to open air. I've heard of driveability problems caused by loose gas caps, why wouldn't the same principle apply? Perhaps a golf tee stuck in that line? Then where does the pressure in the tank go? drip straight into my cylinders while it's sitting?

Seems to me that when people decide to "get rid of that thar `missions junk" they end up with unintended consequences.

 

[Hahnsb2]

The bottom of the throttle body between the 2 larger hoses' is a small vacuum port, there is no solenoid, it runs straight from the canister to the intake.

 

[Wicked_Sludge]

you can connect the canister to any open vacuum port, it doesnt matter which one as they are all manifold vacuum.

dont cap the canister off as this will cause the tank to build pressure, which it will expell where you dont want it to (eg, it could leak).

loose gas caps will trip a check engine light on newer rigs due to the computer periodically testing the tank to make sure it holds a vacuum. your truck is years before this technology and leaving the tank vented to the atmosphere will not hurt the truck or cause any driveability problems.

your absolutely right about people causing more problems than solutions by attempting to disable emissions equipment.

 

[Natedog]

Don't know about the later 2.9s but the charcoal canister on my 86 is connected to a port on the bottom of the throttle body, there is no purge solenoid on my 86 either.

X2....my 87 same way from the factory. 88's are the same too.