Few small smog ?s, new trollhole carb

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Nov 15, 2008
Tampa, FL
Thanks in advance for any help, I studied the forum for weeks before diving into my desmog this morning. The good news it is ran this afternoon with a new "Trollhole carb" installed. Bad news is that I found a lot of vacuum tubes that were already split and disconnected, ran a little rough after install. PO had apparently done a small desmog previously.

So most of my questions are regarding existing vacuums or breathers that aren't hooked up and don't jive with Jim C's desmog schematic.

81 fj40- Trollholes carb has only single ported vacuum, I have it hooked up to inside port on dizzy advance.

Charcoal canister has three exiting tubes, one I assume is coming from the fuel tank. Second line, went to the Outer Vent Control Valve was rotted through, it used to hook to carb through the OVCV... should I just cap it? The third line leads to the VCV for the EVAP system. I kept the VCV... but it only connects to the BSVS and needs vacuum. Since I don't have any more carb vacuum ports I assume I should just cap second charcoal line, remove VCV and cap all BVSV ports? Or should I just hook one charcoal canister line to the intake manifold/carb base line to let it breath?

Crankcase PCV. Cap it or do I need a catch as some have described?

"Gas filter" on the intake manifold(not fuel filter). Has three lines to it, while capping two it just broke in half!! Any ideas on size of port so I can cap it? Is it the same as the BSVS valves, they look the same size?:doh:

VCV between dizzy and HIC/HAI. Once again, can keep it but it has a line to the above mentioned "gas filter"... if its broken can I just remove it and send all dizzy vents to airfilter?

EGR cooler flex tube. Cap it or remove the entire cooler. It looks like it will be a bear to remove due to severe corrosion. Any help on cap type or size?

I'm hoping some guys that put a Weber on (also only one vac port) or Jim C can help!! But I can't complain, its running at least!

75% of what I was unhooking has split lines, all the EGR tubes were rusted with holes and the previous owner had removed the air pump.... at least it made my decision to remove it all easier!

Forum rocks... the desmog wasn't that bad with the help.:beer:

Thanks Trollhole for a great carb and Jim for airrail plugs!

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No help... well, here is what I did!

Well, no responses from the experts. I figured I'd get something from pinhead, poser, trollhole or Jim C...

But after reading the entire emissions book and figuring out how all these switches work... Here is what I've done, right or wrong. Cruiser is running great!

EGR: Blocked the inflow from exhaust(front of EGR) but kept suction (metal tube exiting rear of EGR). That also allowed me to hook the PCV valve back up with the factory setup. Two birds with one stone. Actually 3 birds. Since the vent at the top of the dizzy needed some vacuum (previously was hooked to VCV) I used a T just before the PCV to connect all three.

Dizzy: Two vents on top of 81 dizzy. One vent as above, the other vent to "filter" on the firewall (1981, don't know if all have this). Advance diaphragm.. port closest to dizzy hooked to advancer vacuum on carb. Left high altitude (port farthest from dizzy on advancer diaphragm) alone.

EGR cooler: Need to make cover plate or plug for exhaust inflow.

"Gas filter" on intake manifold: may need to order this, plugged temporarily. Unless someone can tell me how to plug it. Threads are much more fine than typical 10mm bolt.

Charcoal canister: OVCV line is only open when car is turned off... so I capped that one at the canister. Second line hooked to the VCV valve on drivers side. T vacuum from base of carb to the VCV valve-so when the engine is on, there is vacuum and suction through the VCV to the charcoal canister. From what I understand about how these work, it may have a little gas smell when the car is turned off it shouldn't smell like gas after filling the gas tank as I've heard about.

Removed everything else... capped BVSVs since I couldn't remove them without draining coolant.

Timed engine to TDC and it is running very well. May need a little fine tuning. Interestingly, timed it last night with a few of these vaccum sinks unplugged... and couldn't get it to TDC, today it was dead on.

I'm still up for any suggestions if the above sounds crazy.

Let me say this... to all thinking about a desmog, it is really easy if you read a lot about what not to do. Also study Jim C's schematics. The emission book is also very helpful because it explains why you hook one port to suction and one to air or vice versa! Emission book was bought from a Toyota dealer in Texas, can't remember name, inexpensive compared to these parts. The emissions book also tells you the correct way to hook up everything (the parts have labeled letters or numbers which correlate to the book description and pictures). Someone should put this on pdf... but I'm sure Toyota would frown at that. Knowning that VCV stands for Vacuum control valve... and so forth also made it easier to understand IMO.

Be preprared. Order air rail plugs, plan on how to plug EGR and whether you need Jim C's pulley or will devain airpump.

I thought these schematics were crazy the first time I looked that them, now I could put it all back on in a couple hours!

I took a lot of pics pre and will take them of post. Will scan in some diagrams from emission book so we can all understand how the canister and the VCV valves work.

One more thing, Trollholes carb was a bolt on operation. Easiest part of the whole thing. Started on first turn. Jim C's setup is probably better as you retain some vital things such as anti-dieseling switch, high altitude controls and are tuned to desmog.

I'm still up for any criticism or recs!!:beer::beer:

cliffrdavis, following this as I'm thinking about "completing" my desmog. Some components were removed when I bought mine and I've already removed the air rail. Been reading the schematic and have yet to get my head to figure it all out. I have an emissions manual and will study that further. Mine is a 77 and doesn't have as much good stuff as yours did. I know I want to keep the charcoal canister and I've already purchased the goodies from Jim C. Keep running it through my mind and will eventually grow some hair on the cajones. Thanks for the information.
Pics on they way

Got a bunch of pics, I'll label them to make it easier.
Pics for desmog with Trollhole carb

Driver sided wheel well. New Trollhole 2f Carb.

I left the single VCV in place (sky blue line on right of pic) to keep suction to the charcoal canister (yellow line).

The Purple arrow and the wavy blue arrow are connected to a T that then attaches to vacuum at the carb insulator plate. From what I understand about the VCV this should provide airflow/vacuum to the charcoal canister when the vehicle is on. I didn't hook the caniser line directly to the suction as I didn't want to make a strong vacuum in the fuel tank.

Green arrow shows where the vacuum flow from the EGR (barely visible below the carb) is connected to the PCV line. EGR and EGR cooler are temporarily pluged.

IMG_1590 (Small).JPG
more pics- Trollhole carb w desmog

Green arrow to PCV valve to crankcase. Blue arrow to one dizzy vent (two vents on top of 81 dizzy), red arrow goes to EGR vacuum shown on above pic. This entire setup is under constant vacuum.

Orange arrow to "filter" on firewall that leads to the other vent in the distributor. Apparently clean air is drawn in this line and pulled out through blue arrow line. Dizzy pic below.
IMG_1592 (Small).JPG
more pics - Trollhole carb w desmog

Picture of the dizzy. Green arrow to the vacuum shown in pic above (blue arrow above). Blue arrow shows hidden second vent in top of dizzy leads to firewall air filter (orange arrow in pic above).

Purple arrow to primary advance - only one attached to advancer port on carb.

Orange arrow - Hi Altitude advance, not attached as I don't have altitude compensator on and I live in FL.
IMG_1595 (Small).JPG
More pics - Trollhole carb w desmog

Charcoal canister:
Orange arrow fed to the Outer Vent Control valve (green electrical box in pic), it was rotted out and may explain why it always smelled like gas in my garage! This is typically attached to float bowl on stock carb and canister is suppose to absorb fumes while truck is parked, the valve closes when switch is on. I capped it as there is no float bowl vent in this carb.

Blue arrow connected to VCV valve shown in pic 1. Has mild vacuum with vehicle running, hopefully will keep fumes from building up in tank and prevent overflow fuel smell after fill-up.

Green arrow- return line to tank, didn't touch.
IMG_1594 (Small).JPG
more pics- trollhole carb w desmog

pic from driver side wheel well of new carb.

Green arrow- stock throttle attached seamlessly to new carb.

Orange arrow- Vacuum from EGR going to PCV (pic 1 and 2)

Blue arrow - vacuum to VCV valve in pic 1 from insulator plate.

Red arrow - single 12v positive connection, two connections are available from stock carb. Just checked both wires with tester with and without ignition on. Black wire was hot with switch on. No ground.
IMG_1599 (Small).JPG
More pics - Trollhole carb w desmog

Just a pic from drivers side showing lack of tubes everywhere and no air pump. Apparently, PO had removed my airpump, no extra pulley. A/C compressor has not been hooked up since I owned it.

Air Rail line was open to engine compartment when I started - but I never noticed because it didn't make a lot of noise and was directed towards the floor. Guess that could make some exhaust smell too!

Thanks for the help again.

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Sorry to have not responded earlier. I don't know much about "desmog" because I live in a smog control area. My personal view is that desmoging isn't worth the effort and may cause more problems than it cures.
A few things:
The inside port on the distributor is retard. The outside one is advance.
Keep the charcoal cannister and PCV. They serve a useful purpose.
Many thanks........this helps me a bunch. I'm a picture kind of guy and it now seems much easier. I have a few things different but I think I can put it together now. Thanks again.
Sorry to have not responded earlier. I don't know much about "desmog" because I live in a smog control area. My personal view is that desmoging isn't worth the effort and may cause more problems than it cures.
A few things:
The inside port on the distributor is retard. The outside one is advance.
Keep the charcoal cannister and PCV. They serve a useful purpose.
Pinhead, maybe thats in different years. On the emission book, the engine manual and Jim C's schematic it says the High Altitude comp vacuum attaches to the outermost of the diaphragm and causes another 6 deg advance when above 3900 ft from HAC valve. The main advancer vacuum port attaches to inner port on diaphragm of dizzy through the BSVS. I guess just capping the outer port would be fine.

Mossman, I found that Man-a-Fre had a cheap EGR exhaust cover (exhaust port under engine that leads to EGR cooler.). It was about $10, came in two days and fit perfectly. I don't have a welding shop so it was well worth it instead of cutting one with a grinder and fitting it to the exhaust hole. PB blaster came in handy with very long ratchet extensions. Mine had a shot gasket that I replace with high temp ATV.

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