What is this thing and why do I have a vacuum leak there? (1 Viewer)

[GetItBilly]

The "air filter" thing, part 17810A in the diagram below, where the vacuum line passes through the firewall behind the blower motor on the passenger side. Does this line control something on the heater? I've got a bunch of smoke coming out the inside the cab when I do a smoke test.

 

[pithicus]

I have an idea that filters tube goes to the distributor cap

 

[Infinity00]

^^^ what he said^^^ should be the air filter for venting the Distributor.

is that where your smoke is coming from during the smoke test?

there’s a valve that goes bad on the line that goes from the other connection on your dizzy to the valve. Take it off and test it, it’s probably bad. Most are.

 

[Infinity00]

Check post #20 and examine Distributor vent drawing

Finally started my desmog. Updated with baseline vacuum routing drawings

Months ago I bought all the desmog components from Jim and some new boost controller silicon tubing (I have the McMaster stuff on there now but sometimes it has torn pretty easily where I can’t see it). Anyway, getting excited about not have puréed smog vanes going into my air cleaner anymore...

forum.ih8mud.com

 

[GetItBilly]

Well, I'll tell you what, this explains a lot considering this truck has an LS swap and that line has been been running open, tee'd into the brake booster. I'm extremely happy this is going to be solved with a cap on the tee rather than having to take the heater out. Plus, my fuel trim readings are probably going to look a lot better.