Un-doing an emissions delete - need to pass emissions

[Shopmyers]

Hello all

 

I searched past topics and couldn't find a thread specific to my case. I inherited an '82 720 with an Emissions Control System that was completely removed. In my state (AZ), the truck passed the emissions test, but failed the equipment test. Essentially all of the emissions control system was removed and the three hoses coming from the canister were cut and just hanging there.

 

I can easily connect the fuel tank vapor vent line, but since the current setup is so drastically different from the original, I'm unsure where to route the Ported Vacuum and Canister Purge.

 

There are three diagrams - the original, my truck, and my proposed solution. Looking for some help from the community to ensure I do this right! I appreciate all of the feedback.

 

Factory Diagram:

 

 

My current setup

 

 

My Proposed setup

 

[Shopmyers]

Here are some photos of my carb and surrounding equipment:

 

[datzenmike]

Connect the  canister purge (your Brown)  to intake vacuum

 

Connect the  vacuum advance (your Pink) to where it goes in the top picture, get rid of the purple.

 

Previous owners are idiots. Ripping all this off makes it run worse and not improve anything.

[Shopmyers]

Thanks Mike. I'll add a T and connect the vacuum advance in the same way it came from the factory.

 

For the canister purge to intake vacuum, are you recommending to connect it to the air cleaner assembly? There are two ports under the air box assembly that are currently unused. Revised plan #2 below:

 

[Shopmyers]

Or rather, should there be a port on my intake manifold that I can connect to?

[datzenmike]

Find the Boost Control Unit and the AB Valve it the very first picture at the top. Both have a black hose that goes to a fitting on the intake.

 

 

It's in this picture just under the float chamber but someone has removed the fitting and put a bolt in the hole. Like I said previous owners are idiots.

[Shopmyers]

Thanks Mike! I'll do this over the weekend. One more question - should I be concerned that I don't have a Boost Control Unit? Mostly from a safety perspective.

[datzenmike]

Depends on the emissions test. The Boost control works the BCDD (boost control deceleration device) It opens a small carburetor inside the carburetor to provide air and fuel when the throttle snaps closed at high speed and the vehicle decelerates. Normally the engine would go lean and misfire dumping hydrocarbons into the exhaust. By adding a small amount of air and gas it will burn off better. This is only high speed deceleration when the manifold vacuum spikes. I doubt they test for this.

[Shopmyers]

Hey Mike - just wanted to follow up and say thank you. My '82 720 passed emissions with no problem after following your guidance.

[wayno]

It's always nice when there is a happy ending.

I would connect the fuel tank vapor vent line to the canister, there is no point deleting that line.

Arizona must not be as strict as California.

Edited October 31, 2019 by wayno