vac line removal adventure

[rigel]

so i couldn't find the vac line removal diagrams, they were hosted somewhere that didnt keep them.

instead i'm going to document my vac line removal adventure here, because i think i might want to re-add certain functions of the stock carb, like the automatic choke or the secondary throttle diaphragm.

after re-torquing my head and checking that the compression was good, i decided to reinstall the stock carb and try to just simplify it.

removed black box
removed main set of hard lines
removed all those goddamn solenoids and valves
spent $3.50 on an assortment of vacuum plugs

also i figured if the car is just sitting in my driveway while i test it out, i don't need to filter the intake air. this might be a mistake, but at least there wont be soot or schmutz clogging up the hard lines

i plugged the manifold vac takeoffs on the top of the intake manifold runners and by the firewall. i plugged all the vac lines on the carb and reattached the fuel line and coolant line.

i started her up and she ran, but i had to open the butterfly/choke by hand if i wanted her to stay running. which is fine at this point. still on jack stands, not road worthy yet. it's about to rain for the next 4 days and i dont have a covered garage so i'll post pictures in a few days when it lets up.

I have a few questions for the gurus here.

what do i do about the vacuum-based timing advance?
how should i connect the charcoal canister?
do i need to close off the EGR valve and the air suction valve? i mean, do they leak vacuum normally? i know lots of you folks have crimped them off but for some reason i'd feel better just drilling a piece of scrap aluminum plate and torquing it down over a gasket to close them off.

[2ndGenGuy]

For vacuum advance, I would refer to what the Weber guys do. Either you hook it straight to manifold, or find a port on the carb that has vacuum when you want to advance timing.

I think most people just disconnect the charcoal canister and toss it out. Your gas tank just vents to atmosphere, instead of re-burning this way. Again, hooking up the canister is a matter of figuring out what conditions that it needs to properly operate. that may mean hoooking up some of the components that you removed.

EGR valve is best to leave disconnected. You don't want the valve opening under the wrong conditions, or you basically introduce a vacuum leak. Most people buy the fancy $5 blockoff plates on eBay.

If you cut the tubes off of the exhaust manifold, you will definitely want to crimp or plug them at the exhaust end.

[Ryon Toth]

2nd gen guy is right. But if charcoal can is removed, per 3geez instruction (a20a1 i believe) run a line from can to a "tee" with a filter and the other side to the carb ( if carb pertains) i however, did not and vent to atmosphere. I have a weber 32/36, a20a1( with less than 50,000 mi) carb, efi cam, and she runs really well. Absolutely no vaccuum controls. I may need to run a line from back of carb to #25 on dizzy advance but she has been my first toy.......

[rigel]

what i'm most concerned about is the venting of gas fumes out the back of the carb. it seems like a rubber vacuum cap wouldnt stay on because it's under outward pressure. i'd prefer to avoid an engine fire.

[2ndGenGuy]

Are you talking about the port on the back of the carb? That's a vacuum port that only has vacuum at part throttle. If you're at idle, there is no vacuum, and if you're more than like 20% open on the throttle, there will be no vacuum again. I'm not really sure if that's ideal for the distributor or not, but a lot of people seem to think so...

There should not be any outward pressure on it, unless you have a backfire. A backfire can blow the cap off, but if you install one, just put a zip tie or tiny hose clamp on it. A backfire can also blow out your power valve or accelerator pump diaphragm (though it's rare). You definitely want to cap that if you're not using it, or you're pulling in unfiltered, and "unmetered" air.

[rigel]

yeah, the one with the nipple right next to the fuel cutoff solenoid. when the car stalled after starting her up, there was definite escape of gasoline vapor from there, but maybe thats why it was stalling too. i'll try a clamped vacuum cap and see what happens.

[rigel]

7800

i cant tell if that upload worked or not, but this is my proposed vac diagram (in red) in order to keep the distributor vacuum advance, vacuum controlled secondary, and the choke circuit. basically in order to do that i don't need any solenoids or anything, but will need to wire up all three thermovalves.

[Hazwan]

Depending on how cold where you live, the electric choke alone should be enough to keep the car started and running on the first start if you wanna get rid of the vacuum controlled choke and its fast idle stuff.

[rigel]

i would be fine disconnecting the lines for it, but wouldnt the fast idle cam be engaged all the time that way?

[Hazwan]

As far as I remember, the electric choke mechanism would still release the fast idle cam once warmed up

[rigel]

so i just got it off the jack stands today and it seems to be running pretty well now, knock wood. however, i need to place a little bit of tension on the gas pedal at all times or else it stalls. since i dont have the idle boost controller connected, i'm thinking that i should just adjust the throttle cable so that there's a little bit of tension on it at all times? it's obviously an old cable so i am assuming theres enough extra stretch in it that the 3mm housing/mounting length suggested by the manual is no longer appropriate. or is there another solution?

[Dr_Snooz]

You can do it like that, but you'll probably find that it's not very precise. Expect a very inconsistent idle.

[rigel]

i wound up screwing in the idle limit screw and using some bare wire to hold the butterfly open. it can take a few minutes to start when it's colder out but it no longer stalls at all (knock wood) and has a rock solid (if a little high at 1000 rpm) idle while in gear with the brake engaged. at the same time i realize that the whole idle choke opener/fast idle unloader circuit isnt doing anything while its wired up like that. regardless im pretty happy with how it drives now.

our family's other car got stolen recently, so i really needed to rely on the honda to get to/from work. we bought another car, and the next day our stolen car shows up less than a mile from our place. so once the insurance company takes a look and we get new plates, i will be able to dedicate the 3gee to full-on tweaking. i'd like to see what kind of performance (which to me means mileage) i can get out of the stock carb. i guess that means playing with the a/f mixture screw, the other limit screws, and eventually maybe the jetting. should be fun.