1984 Toyota Tercel, SR5 4wd (3A engine)

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WhitneyDesignLabs
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My tercel:: 1984 Toyota Tercel SR5 4WD
Location: N. AZ, USA
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1984 Toyota Tercel, SR5 4wd (3A engine)

Post by WhitneyDesignLabs »

Trying to get it running. Brake parts will be here soon.
So I am a bit stumped on this ol' carb. Idles for a few seconds, at best, then dies. The last few days of inquiries leads me to think there is a HEAP of superfluous emissions and vacuum stuff going on - and the factory carb seems very complicated. In N. AZ, I don't suspect that I would ever be required to make this car pass emissions that justify all the extra foo-for-all. Normally, my first thought would be to remove car, get rebuild kit, Chemdip it, re-install, good as new. But this carb and all the wires and vacuum, is a bit daunting. I am debating a new, Webber carb with adapter.
1984 Toyota Tercel, SR5 4WD
1990 Geo Metro
1995 Geo Metro
2005 Subaru Outback XT Limited (turbo)
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Petros
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My tercel:: '84 Tercel4wd w/extensive mods
Location: Arlington WA USA

Re: 1984 Toyota Tercel, SR5 4wd (3A engine)

Post by Petros »

usually in most states if it is over 25 years old you are exempt from testing. OTOH, there is federal reg that is is unlawful to disable or tamper with a federally mandated emissions device, however, there is no means to enforce this rule since there are no federal emissions police. it is up to the states to enforce it, even though most just make older cars exempt from it.

I have owned and driven cross country Tercel4wd with both the weber and the many with factory carb and emissions systems installed. if it is working properly I like the stock carb better. it has better performance at both extreme cold and extreme hot start ups, and has good drivablity at all speeds and rpms. There is really no reason to be intimidated by the factory fuel system, read the through the fuel system and emissions chapters in the factory service manual (FSM) and trouble shoot the system. if you take one component at a time, do the simple FSM tests, and work your way though them, and than do all the proper carb and choke linkage adjustments, usually you can get it to run well and trouble free for many miles without tuning or maintenance. the factory carbs, despite their complexity, is really very reliable. OTOH, often times previous owners, or even mechanics, who do not bother to learn about how these systems operate, will often mess around with them trying to get them running properly, and only make them even worse and more difficult to fix. because now they got the vac lines all messed around. some have even removed systems thinking it will run better. hint: the fuel system needs most of those systems to run properly, removing them will only make them always run badly, if at all. Even so, the are not that hard to learn about, and keep running well. you can down load the FSM from elsewhere on this site for free.


The Weber will run without all the other emissions stuff, and if you want to remove it all installing a weber makes that a viable option. the Weber does not noticeably put out more power, and fuel economy suffers a bit too, but it greatly simplifies the engine compartment and the fuel system. if you will be making a lot of mods to the engine than the Weber has a lot of different jets you can use to optimize it for the performance of the engine configuration. If you get a jet kit and than experiment with various combinations of weber fuel and air jets, you can bring the fuel economy up to about the same as the stock carb, without all the complicated emissions systems. Do not expect it to be properly jetted as it comes out of the box (the supplier who sells the kit claims otherwise, but I have driven one with out of the box jets and the economy was terrible). Also, it is not quite a simple bolt on carb swap, there is a weber thread in this forum that shows what others have done, how they altered the throttle linkage, and how they jetted it, etc. so you can get a head start on it if you want to go that way. the weber is also more costly than getting the factory fuel system rebuilt and operating well.

With this information you can make a better educated decision on the carburetor you install. I suggest that perhaps you spend some time getting the current fuel system to work well, and than decide if you want to switch to the weber. it will give you a better base line so you know what to compare the new weber against.

BTW, often a poorly running carb/induction system is usually caused by vacuum leaks, and/or misrouted vac lines (easy to fix once you find the problem). sometimes some components fail, many can be by passed without problems, and if done properly it will still drive well. And as a last resort you may have to rebuild the carb, or take off the top and carefully clean it out. Occasionally the carb is worn out, or has too much corrosion (from the federal ethanol blend we now get), and it can not be rebuilt. if so, that would be a good time to consider a weber, a new weber is way cheaper than a new or remanufactured stock carb.

Good luck.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
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dlb
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My tercel:: '87 sr5, '83 dlx parts car
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Re: 1984 Toyota Tercel, SR5 4wd (3A engine)

Post by dlb »

A weber with the adapter is $200-300 IIRC. They are easy to swap in for the most part but there are a few annoying details -- on some t4's, the weber will not fit under the hood (even with the short air filter) so you may need to figure something out for that (I went with a hood scoop on mine). You also need a fuel pressure regulator for the Weber. The weber was fun, a lot more responsive than the stock carb, but I grew to love the stock carbs once I came to understand the various emission stuff better. I agree with Petros, I would mess with the stock carb a bunch before spending the money on the weber but some here really prefer the weber.

Idling for a few seconds and then dying sounds like either a fuel delivery issue, or big vacuum leak(s). First thing I would do is replace the $5 fuel filter which is a 5-minute job. Then make sure all the hoses are connected (especially the big hose that connects to the bottom of the air filter housing) and the carb mounting nuts are snug. Occasionally I have seen loose intake manifold bolts but it's rare.
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WhitneyDesignLabs
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My tercel:: 1984 Toyota Tercel SR5 4WD
Location: N. AZ, USA
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Re: 1984 Toyota Tercel, SR5 4wd (3A engine)

Post by WhitneyDesignLabs »

Thanks for so MUCH valuable information! You guys are awsome. I have to set this project aside for a couple weeks. I will let you all know how it goes when I get back to her. My thoughts are to spend more effort on the stock carb, and failing luck with that, bite the bullet a get the Weber.
1984 Toyota Tercel, SR5 4WD
1990 Geo Metro
1995 Geo Metro
2005 Subaru Outback XT Limited (turbo)
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