88 FJ62 BB style desmog. (1 Viewer)

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May 16, 2020
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Fayetteville AR
I’m working on the BB style desmog hack. I have read many many threads on the matter and feel like I understand the process.

One question I have is related to my 88 FJ62. The vacuum hoses ends ,for the majority, run into a bank of sensors mounted to the Left hand side (drivers side) fender. In this case, do the BB’s belong on the hose ends that plug into the sensors? See picture attached. The green are the two “loop backs” with no BB’s. The red is where I believe the BB’s go. 6 in this picture. Is this there a 7th?

DCB8D324-9E35-4D03-8F9A-55A0A2232024.jpeg
 

mattressking

10 digits to freedom
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Ventura, Calif.
You plug the end that is pulling vacuum. The sensor, otherwise known as a vacuum switching valve (VSV) uses vacuum to operate along with a trigger from a 12v source. Look at the Factory service Manual and it will tell you the routing. The fast way is to either follow the hose(s) and you'll see its source - which is always the intake manifold or start the truck (if you can) and feel the vacuum pulling then block the hose off at the source. Unplugging and putting a screw/BB or whatever into the line....is the lazy method...it's great for temp fixes or testing. Otherwise remove all the hoses that will not be used for the desmog and use a quality silicone vacuum cap to restrict vacuum.

Don't go unplugging and hoping for the best. Read the smog diagram - understand what you're removing.
 
Joined
May 16, 2020
Messages
87
Location
Fayetteville AR
You plug the end that is pulling vacuum. The sensor, otherwise known as a vacuum switching valve (VSV) uses vacuum to operate along with a trigger from a 12v source. Look at the Factory service Manual and it will tell you the routing. The fast way is to either follow the hose(s) and you'll see its source - which is always the intake manifold or start the truck (if you can) and feel the vacuum pulling then block the hose off at the source. Unplugging and putting a screw/BB or whatever into the line....is the lazy method...it's great for temp fixes or testing. Otherwise remove all the hoses that will not be used for the desmog and use a quality silicone vacuum cap to restrict vacuum.

Don't go unplugging and hoping for the best. Read the smog diagram - understand what you're removing.
Many thanks! I fully intent to remove the smog system in a comprehensive manner. The BB hack, at least for me, is a test.
 
Joined
May 16, 2020
Messages
87
Location
Fayetteville AR
update. I plugged the ends of the vac tubes that were pulling air with a BB. measured the vac "Pull" by hand, without a tool. any vac tube that I had trouble to ID the end that was "pulling", I doubled down and blocked both ends. This is a list of results.

1) Instant improvement to starting, in sub freezing temp. Starting up without any 'Throttle" knob, became easy.
2) Instant improvement to ideal. much smoother and consistent. In PARK, it is "purring". much smother and more quiet.
3) I can tell there is more throttle response in low gears.
4) The smell of the exahust does smell different....I bit more phasphorus smelling.

I now plan to remove all of the SMOG system components. I expect even more improments as I think there are a few Vac tubes that should have been plugged that were not. I may be wrong, and if so, the current improvments will make it a worth while effort.


I still have a many improvments to make, which i will post on.
 

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