Perhaps I will drive to the junkyard tomorrow

[3A-C Power]

I don't think carb cleaner works for testing vacuum leaks. Depends what kind it is, but the stuff I use will not make the engine run any faster. If you spray it into the carb, it slows the engine down. They put the intake on top of the exhaust and bolted them together to transfer heat when the engine is cold by means of a flow directing plate controlled by a bi-metal spring. It makes theengine waste less fuel during warm up but ultimately hurts the efficiency because the heat conduction is always there, warming up the intake. If you take a look at the intake and exhaust manifolds for the dual-carb setup on Japanese 3A-SU engines, it looks like a better design - more equal length seperate runners and no heat transfer section between manifolds.

[Dirtmagnet]

I just readjusted my carb today following the steps in the FSM. I had done bits and pieces, but it is important to follow these in the sequence they show. The car is running better than it has since we bought it.(it has 191,000 miles on it now)

I did drill out the plug on the mixture screw when I rebuilt it and after getting the initial settings, I adjusted this. I went 1/2 turn out from stock setting to get the best results. I had this mixture way off (from stock)and I think this is one thing that was giving me fits. It is 62 degrees here today so I hope this doesn't change when the weather turns cold(OK cool) again.

Next week I tackle the sway bar end bushings. Thanks to Takza for a great write-up on this.

[Adelard of Bath]

Well, if things continue like they have been, I may retract my statement about "driving to the junkyard..."
Had the intake and exhaust manifolds off, cleaned everything up nice nice nice, new gaskets, blah blah blah, everything so far is good, and things have been going together nice and easy. Perhaps the car is no longer fighting me, since I am being good to it now...heh
Since the exhaust manifold was off the car, I took the time to drop the exhaust pipe...there was a leak in the cat that was driving me crazy. So a few minutes with the wire wheel on the grinder shows me THREE places that it has rusted through....so some time with the welder (during which my coat sleeve was in flames, sweet) and those are plugged...also that line that goes up to the non-existant air pump, cut that off and welded it shut.
Yay!
Few new bolts tomorrow, get that back on, then put the completely sealed EGR valve back on (minus vacuum lines), then the carb with THREE new gaskets (what a rat's nest of possible leaks there huh) and I am hoping that it runs alot better than it did before, with lots of bad gaskets. While the carb is off I am going to drill out that adjustment plug for the mixture...but I have a question about that; as near as I can tell, that just adjusts the IDLE mixture....how do you control the mixture at everything above idle? Just the size of the jets? If that is the case....that's crappy, man.

Okay then here's a question that may be important: When the car was running before, and I pushed the brake pedal (my spongy spongy brakes) the idle would drop momentarily...if I pushed it repeatedly, in rapid succession, it would almost die. Is this normal? Brake booster going out? Or just too many other vacuum leaks for the engine to keep up with trying to suck it all out of the brake booster too?

[Typrus]

Brake thing is the same with my car. It's probably some vacuum yummy-ness. Occasionally, the alt and brake light going on can mean your alternator plug has vibrated out. I had a problem with this, so I created a make-shift gasket to replace the missing one, no further problems yet. At this rate, if you have $450 to spare ( who does?) you may just want to go for Mr. Weber. That is, if the rest of the engine is in decent shape.
I don't have the problem with dying just above idle or anywhere in between, though it is pretty gutless in comparison to WOT. The problem I have is a very shakey idle at anything above natural idle and very rarely does true idle keep my engine alive. It likes to die with no throttle stimulation. I had my mechanic dork around with my mixtures and his verdict was;
"Look, I tried to solve the problem but as far as all my diagnostics can tell, it's just an old and dying carburator and unless you want to spend more on fixing it than you did on the car ($400) then I suggest you just live with it untill you can afford a new ride or the repairs. Sorry Chris."
lol. My mechanic is a very nice guy luckily. I dunno if I said, but the complete rewiring of the radiator fan system and replacement of some wires between the alt and battery only cost me $86. Other garages quoted anywhere from $120 to $200.
Anyway........ I realize your baby is dying on you Adelard, but again, don't give up on her just yet! You might want to check your car ads and local market for a cheap Terc in good shape to potentially transfer the engine to, or just to replace ole' (t)rusty. I really don't want to picture a front end impact with a crumbling frame. You may not have to worry about your driving, its the other dorks on the road.
I realize it is tempting to just walk away from it, but where is the fun in that?
Any change with your fixes?

[takza]

While the carb is off I am going to drill out that adjustment plug for the mixture...but I have a question about that; as near as I can tell, that just adjusts the IDLE mixture....how do you control the mixture at everything above idle? Just the size of the jets? If that is the case....that's crappy, man.

Okay then here's a question that may be important: When the car was running before, and I pushed the brake pedal (my spongy spongy brakes) the idle would drop momentarily...if I pushed it repeatedly, in rapid succession, it would almost die. Is this normal? Brake booster going out? Or just too many other vacuum leaks for the engine to keep up with trying to suck it all out of the brake booster too?

The idle mixture being made a little richer might help the mixture above idle to some extent...possible that the idle circuit still adds something above idle.

Spongy brakes and dropping idle sounds like the master cylinder going out...or air in the lines...or both.

[Adelard of Bath]

Thnks for the support, Typrus! The last week or so, I have been enjoying my car, which is how it should be! I don't mean enjoying it by driving it, I mean enjoying it by rebuilding it properly....now I know that the intake manifold and all those things don't leak or anything...and holes are welded shut, blah blah blah, it is fun!

I had the carb back on today, and it starts better now that I fixed the intake leaks, but I still have this one sucky problem, and I think it is slightly different than before but similar! When I open the throttle slowly, it works great. when I open it quickly, it just bogs...and right before it dies, I mean, just when you are 100% sure it is dead, but still watching the carb, suddenly it comes back to life! Very strange. And actually, if I hold my hand over the primary barrel, the problem is mostly reduced....so I figured it was lean.....I guess.....although I can't figure out why it would matter how fast I opened the throttle. Accel pump is squirting nicely....so I thought I would turn my mixture screw slightly, just to see if anything happened, and found my screw to be totally f'ed up....so I removed the carb again (actually i'm quite good at it now, nice and easy!) and finally got the screw out....then used my lathe to machine the messed up screw-head off the "needle" and made an extension out of this other brass thing, then made them mate nicely (i love the lathe) and then soldered them together...heh if my calculations are correct, I will now have a brass post sticking out of the carb, and I can just turn that, instead of trying to stick a screwdriver in the hole....hehhehe I have yet to go put it in though.

Oh I unhooked all the EGR stuff and plugged the lines, when I get it working I am just going to remove the applicable lines cuz my EGR is defunkt. I think I will plug the fitting on the manifold for the brake booster just to remove that from any problems...maybe my diaphragms on the distributor are leaking too hee hee I will have to check those, I am glad I bought that "mity-vac" tool!

[Adelard of Bath]

Takza: I bet the idle mixture screw is like a "base mixture" to which the jets add their own fuel..but always everything is added to the base mixture?
at least that is what I am figuring.

I probably have air in my brake lines....oh get this, when I bought the car, the guy had only one rear brake operational, cuz I guess they hit the brakes and a rusty brake line exploded and so he unscrewed the line and put a bolt in there with teflon tape where the hoses are on the axle...so I replaced the line and the cylinder, and bled that line...but when I looked at the rustiness of the bleeder screws on the other three brakes, I figured that my chances of getting those loose without snapping them all off was about 1/870. Sooo...I am holding off on that...but perhaps someday, if I work on the screws long enough...or just buy new calipers and cylinder.


ANYWAY....I am going to fix this car, whether it likes it or not...heh! Then once it is fixed....then I might sell it cuz the fun will be over..but as long as I have it, no giant piece of rust is going to show me who's boss!

[Adelard of Bath]

Well adjusting the mixture did nothing...I am surprised at how little it did. I started by doing the "all the way in, 3.25 turns out" routine, and it started and ran very nicely actually...still did my thing though. So I turned it out a little...and a little more....eventually out like six turns and it was still running exactly the same, although quite sticky like sulpher in there...then I turned it in until it was at like 1.5 turns out from closed and it was still running the same, although a little slower I guess.

Plugged the line going to the brake booster, no effect...

It's GOTTA be some kinda mixture thing cuz when I put my hand over the primary barrel and do the revving thing, it works PERFECTLY but without my hand, it bogs and dies.

(I'll just drive around with my hand over the carb...maybe I should get a super dirty filter and put it on there)

going through the carb *again*
finding more things to check/whatever...
The "accelerator pump" seemed hard to pump, even though it was spraying...and I noticed that it was spraying for a while AFTER I opened the throttle.
Hmm. So I go in there and use my little wire-thingies for cleaning cleaning welders? I dunno I stole it from work one time, it has like 20 different wires of different sizes on it so I used the smallest one and there was something in the accel pump jet...yay. And the FSM shows an oring on that thingythingy thing that I didn't have...part undescribable hehhe so I added that.

Thought I might as well do as the FSM suggests and check the fuel cut solenoids, so there I am, unscrewing it, watching the wires wind tighter and tighter....I thought I could do it but one wire popped! doh. oh well still plenty on there to solder to...heh at least now I know the solenoid works, and the o-ring was bad so I replaced it. Not that the fuel solenoid sealing incompletely will cause my problems...oh well

What is up with those two "jets" that are brass and you screw into the carb by using a regular screwdriver through the two access ports in the front of the bowl? Since when is a "jet" down in the bottom of the bowl? and it is just a screw with a hole in it? All they are is a restriction in the path of the fuel on its way to the venturis. Is it all based on the size of the hole in them or something? Maybe some dumbass mixed em around before me! Hard to imagine, since the thing ran fairly well until one day...i suppose it got cold I can't remember.

Anyway too late at night and cold out and parts breaking and too many gas fumes for a few hours == headache bleah!

[takza]

I have "heard" sometime that pushing wires thru the holes & passages in a carb is not a good thing...some even say not to use a carb cleaner wand. Not sure how you'd clean things out.

I rebuilt a Mazda carb once that was something like that...had a flat spot above idle...when I was done...it was just the same. Think he then took it to the pro....who maybe didn't do any better...cause it was parked after that. To me it drove OK...did have some hesitation in top gear...but livable.

Seems you'd notice something when moving the idle mix?

I guess that jets are jets? That's how they work...restrict flow to a certain rate?

Parts have to seal well and need an o-ring or gasket if it's called for.......gaskets need to seal. Might have the top part of the carb "warped"?

[Adelard of Bath]

You make me think, Takza, which is a good thing...but I don't think anything is warped...at least not that I can tell, everything seems to seal well....

What if years from now, it turns out to be something completely simple and stupid....I had a truck once that I ALWAYS had this one problem with...then four years later I sold it to a guy,,,two nights before I brought it to work for him, I was like "what if I bend this linkage" and viola it worked perfectly, and I was like "DAMN. Four years."

I guess I will have to be careful when using my wires to clean the jets huh heheheh I will just use a drill bit!!! then it'll work

You know....it makes absolutely no sense that you wouldn't be able to adjust the mixture...you'd have to be able to adjust it, cuz that's lunacy, relying solely upon the oriface size of the various brass parts you put in the carb....one year down the line, it would all be different! And air pressure would change and your mixture would be wrong...you'd go in the mountains and it would be all wrong (okay I guess it does do that)...any amount of deposits in there and it would change, and as the carb engineer you can't just say "well they shouldn't get any deposits" cuz deposits are a fact of life.

Oh well maybe I will jsut put it back together and drive it...
Yeah we all know you can't drive around babying a carb, when 95% of street driving occurs at the point where my carb wants to die...well looks like its full throttle for me all the time!

[GTSSportCoupe]

I have not read through this whole thread, so I'm not sure if this will help: From my experience, whenever I have carb problems like you are describing, I find the best cure is to replace the whole thing with a low km clean carb from the wreckers. I've done this on a couple cars now (including one of my tercels) and it solved all my problems. This is after trying all sorts of other troubleshooting methods to solve the problem. Personally I hate carbs and much prefer fuel injection, but thats probably because I know electronics very well and find it easier to understand and troubleshoot.

Good luck!

[Adelard of Bath]

That is good advice GTS...even though I finally got mine working right, I think I may do what you said next time...or just bring the carb to one of those old guys who rebuilds carbs professionally.

I like fuel injection better too, simpler I think! and of course better but that is subjective; I was just talking to my brother a couple days ago and he said "fuel injection is not simpler" and i'm thinking, hey whatever you wanna think man.

I was going to call a guy about a honda CRX for 200 bucks, but then the tercel started to work so I thought, I guess I don't need the crx...
I may still actually, cuz 200 bucks, how can you lose...and research shows that a 1985 CRX Si is fuel injected!
and they's damn coooool