Help me route vac. lines for my Trollhole carb! (Desmog Without HAC)

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Dec 28, 2010
Vashon, WA, USA
Ok, so, after getting my battery recharged, I got the 'ol beast fired up for the first time with my new carb. I'm pretty sure I have most of the (greatly simplified) vac. system plumbed correctly, but I have a few questions that I haven't been able to answer because the Trollhole carb doesn't use HAC.

Here's how I have it setup currently:

(Things in Bold are things I specifically have no idea what to do about; the rest are things I assume are correct, but could be totally eff'd up)

- Big Vent on Top <-> Hard line in far PS firewall (is there a filter on the other side?)
- Small Vent on Top <-> Connected to PS VCV port Z and X via t-connector
- Inner Diaphragm Port: plugged
- Outer (main?) Diaphragm Port <-> Advance Port on Carb Base

Passenger Side (PS) VCV
- Ports X&Z: to the dissy (see Dissy connections)
- Port Y <-> to port on top of Air Cleaner
- Port S <-> One port on three-pronged Gas Filter on Intake Manifold

Driver Side (DS) VCV
- Port S <-> BVSV Outer Port (furthest from thermostat body)
- Port X <-> Air Cleaner
- Port Y <-> Port on Carb Insulator Plate
- Port Z <-> Top of Evap Canister 'Front'

Evap Canister
- 'Front' Port <-> DS VCV Port Z
- 'Back' Port <-> Hard line going back towards fuel tank
- Port With The Pump Dealie and Wires On It <-> Hard Line On Firewall, with nothing to connect it to (the top part of the Trollhole doesn't have the port for that hose that the stock carb had)

- Inner Port <-> Air Cleaner
- Outer Port <-> DS VCV Port S

Brake Booster
- Only Port I Can See <-> Big vacuum inlet on Intake Manifold, with the cooling fins on it, with the little side inlet for the AC Diaphragm (Note: my brakes feel waaaay too firm, so I'm not sure if I have something plumbed wrong here?)

PCV Etc.
- Small Branch From Big Line on PS of Engine, Just Behind Dissy <-> The inlet (HIC valve?) on the underside of the Air Cleaner
- Port on Extreme Rear of Valve Cover <-> Back of Air Cleaner
- Big Line on PS of Engine, Just Behind Dissy <-> PCV Port on EGR Inlet on Intake Manifold (yes, I plugged the EGR side).

So, is anything routed wrong? Is anything missing? Is there anything I have hooked up that really doesn't need to be?

I dialed in the timing and the idle speeds/mix more or less to spec, and went on a test drive.

Runs pretty dang well, though I could probably advance the timing a bit. If I routed anything wrong, it's not bad enough to affect the idle or the performance. Also, while my brake pedal is pretty firm, the brakes are really gripping well.
I totally desmogged--only hose I have left goes from carb to distributor advance. Runs great.
I did a little more poking around. Turns out I had the hose from the advancer port going to the secondary diaphragm on the dissy. So, I switched the hose and the plug.

On the plus side, it does seem to putting out a little more power at higher rpms/loads. Unfortunately, it's also stumbling when I apply the throttle quickly from idle, or when I'm coasting in gear. Needless to say, I'm terribly confused by this new behavior. If I apply the throttle more gently, it revs up quite smoothly. Also, no pinging, even when going up a steep hill in 4th with the pedal to the floor.

Now, another question: with a properly functioning evap system, should the tank suck air when I take off the fill cap? Because mine did when I went to fill up.
Now, another question: with a properly functioning evap system, should the tank suck air when I take off the fill cap? Because mine did when I went to fill up.

I think it's pressurized, not "vacuumized."
Swap the lines on top of the canister since your desmogged. I think they are marked "To Tank" and "To Filter" or something
Others are more knowledgable about how the CC functions than I am...I did the line swap as Klinetime mentions...and still had too much pressure. During one trail run (very hot day) I had fuel coming out of the bottom of the CC. I found this thread and bought one...

It works fine so far (one year later). It's hooked up "correctly" that is the "to tank" port goes to the tank. One difference is that there are only two ports, the evap system port on the OEM CC isn't there. Since I'd removed many of the smog controls anyway, this didn't cause me any grief.
Swapping the lines pretty much disables the canister and theoretically allows no pressure buildup since the tank is vented more openly. It worked well for me. You definitely need it though. I took mine off one time and it smelled very strongly of gas while running.

I also un-plugged the electrical connector thats on it. Zip tie it out of the way.

Let us know if that works for you.

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