Can a Gross Polluter be Fixed?

My 21-year old formerly clean-burning awsome Toyota Tercel hatchback has been on a downward spiral… fouled plugs, too much HC, way too much CO. My mechanic wants to provide a quick fix to pass inspection but I want it back to the truly clean-burning car it was for 20 years. Mechanic says impossible. Is he right?

Depends on the problem. I truly believe there is no problem that cannot be fixed. The question is ‘Is it worth the cost and effort?’. This is a 21 year old Tercel, so probably not worth much in terms of resale. What would you consider a cut-off point to putting money into it to fix this?

I’m guessing this '89 Tercel has a carburetor. Toyota was still using them until mid-1990. If so, you need to have this on rebuilt or replaced. The current one is leaking fuel directly into the intake manifold, causing the overly rich condition your dealing with. Since it’s been 20 years when the last one was sold in a new car, replacements may be hard to find.

If it is fuel injected, your problems are harder to figure out. It could be leaking injectors, over-pressurized fuel system, or even a bad MAF sensor or O2 sensor. It could even be a bad circuit in the ECM itself. Again, parts may be difficult to find.

Of course it’s possible. The cost could be minor or it could be major depending on the reasons why it’s running poorly.

You state the plugs are fouled. Fouled with what; gas or oil? If it’s the latter then you start getting into the area of a potential engine overhaul and this will be pricy.
If that’s the case then the O2 sensor and catalytic converter is likely to be in bad shape also. At what point do you stop spending money on an old Toyota?

If it has a carburetor, it’s time to move on…

Yep carb. Yep oil fouling. No resale – the value is Not Buying Another Car. But it is sounding like carb, cat, and rings are all shot. And I could get a lot of zipcar miles for the cost of fixing all those things. Sigh…

Time to let it go to the recycling center, they’ll likely give you scrap steel price for it(Maybe $200). Use that for your Zipcar fund.

The carburetors are pretty simple to repair and the converter is not a big deal but the oil burning is a deal killer. That will run the HCs through the roof.

Before you can know what’s necessary a few tests will have to be run. Start with a compression test. If the compression is low and/or uneven, that’ll indicate that the cylinders are worn and the rings are tired (they wear and they lose their spring tension). If that’s the case, then you’d need an engine rebuild to get the car back the way it was 20 years ago.

The carb may or may not need a rebuild or replacement. Until you know the condition of the cylinders you have too little information to know why the combustion is incomplete. If the compression test (above) is good, then you can start consideriing the carb.

The cat converter, while you may turn out to need one, can be bought pretty reasonably for this car
but until the engine and carb are brough up to snuff, it’s pretty much impossible to tell if you really need one.

If the car looks and drives good, no rust, suspension in good shape, interior OK, then I could justify repairing it, even if repair costs easily exceed the resale value of the car.

On the other hand, the mechanic probably knows more about this car’s problems than we do. Repair kit for this carb is only $20, but that may not cure all its ills. The only new carb that I could find available for this car is a Weber, and that would not pass emissions test, even it if it ran perfectly, because it is not original. The mechanic may know that there are other problems as well.

Availability of parts could be the show-stopper. I had to retire a 18-year-old Toyota Starlet with 275k miles that looked great, ran great, and easily passed emissions test simply because Toyota discontinued carrying parts for it.

  1. If the repairs are going to be done by a paid mechanic, your choice is clear. The recycler is ready for you, as the car is worn out.

  2. If you are going to do the work, your possible choice is to get your hands on a low mileage replacement engine (fat chance, but you could try!), rebuild that engine, and replace your old one with the rebuilt.

Only dedicated, mechanically inclined cheapskates with access to tools and a workshop would try the second choice. And they would be nuts to do it. The car is not worth the effort.

It’s time to put the little Tercel out to pasture. Take a few pictures, turn around and walk away. Please don’t make it a lawn ornament. It’s had a good, long and useful life.

Awwww… come on guys. Why not do the “quick fix” and maybe you can keep the Tercel going until the next emissions is due (2 years in my state). Then you can take your zipcar or car payment money and put it towards: a. credit card b. mortgage c. IRA d. et-cetera

I’m sure everyone will pile on with explanations of why I’m wrong, but I fail to see how a car that gets 30+ mpg is more of a threat to the environment than these hulking SUVs that get 9-12 mpg.

Out of curiosity, how many miles on the Tercel hatchback?

In a word: “No” He is not correct, unless the car burns lots of oil

I have the same car and had the same problems, which had gotten worse than yours are currently. Most problems with these Tercels are due to the carburetor being of defective design. There is teflon coating on vital inner components that slowly dissolves in gasoline and even faster in ethanol. When these carbs have problems, it causes the engine to run an inappropriate fuel/air mixture (often lean) which can harm the engine and cause lots of carbon deposits, emissions, poor gas mileage and performance. Fixing this can be expensive if you have to pay a mechanic, but is reasonable if you can do some or all of the work yourself.

Here’s what I did to make my 89 Tercel run great. Likely will work for yours too. Follow these steps in order for best results:
1)Put a full can of “sea-foam” or “44k” in a full tank of premium gas and use the whole tank of gas, preferably on the highway. The car will likely run poorly, hesitate and smoke when you do this. The smoke is the carbon deposits burning off. This alone might be enough to pass emissions depending how bad off yours is, but do not do it more than once or twice as the sea-foam erodes the teflon along with the carbon.
2) Test and clean your EGR valve. Mine was so clogged with carbon and wasn’t working at all.
3) Replace your spark plugs, wires and distributor cap/rotor with NGK brand parts - don’t use any other brand for the plugs as that’s what the car is designed for and works best with.
4) Replace the carburetor with a Redline Weber 32/36 kit. (NOTE: If you live in California, this carb is not legal to have on your car.) Installing it can be expensive if you have to pay someone else to do it - I installed mine myself to save $$ (shop quoted me $300ish in labor). The carb itself was about $350. You’ll also need a Redline fuel pressure regulator (accept no substitutes), which is about $80. Instructions from people who have done the swap can be found on the web.

I’m very satisfied with the approx $600 it cost me to do all this myself and would recommend it to anyone with this car and the right budget or know-how. My car has better performance than it did when it was brand new and gets about the same gas mileage, and yours probably will too.

as you can tell from this thread we dont have enough information to do an accurate diagnosis, so guys are just throwing ideas at it. What the heck, why not? Once you do a compression test, and if you find it is generally good, then you will want to replace the valve guide seals as the primary cause of oil consumption. Next the 02 sensor along with the catalytic converter. But please tell us, how many miles on this car? How much oil is it using? (quarts per miles). Is there any change in gas milage? Also, when you have the compression test done, have your mechanic put an oil pressure gauge on it and see what the oil pressure range is from idle to mid engine rpms. Only then will you have the data to base your decision on. At least that is my wild ass guess. good luck with it.

Mr. Cheap, that wasn’t the question. The question was can the car be brought back to the truely clean burning car it was 20 years ago.

If we assume that the OP means cost effectively, the general consensus is that while we’d like some more specifics, it’s highly unlikely. The car sounds old and tired.

Besides, I don’t think anyone has mentioned that that old carbed engine ran pretty dirty compared to totday’s cars anyway, even when it was new.

I think we have plenty of info to answer the original question: Can the car be restored to the clean-burning car it was 20 years ago? With the oil-fouled plugs and worn-out carb, nothing short of a complete tear-down and re-build complete with a freshly rebuilt or replacement carb, with a fresh EGR valve and fresh catalytic converter will get him there. Hideously expensive for a 21 year old beater. If it had any classic value to it, I’d consider it. Not a Tercel, however.

The old AAP diaphragm has a pinhole in it causing it to constantly suck gas into the vaccum
line connected to the AAP.

For a temp fix pinch off the vaccum line going to the AAP with a hemostat clamp.

Buy a carb rebuild kit (should be under $25) and replace the Auxiliary
Accelerator Pump (AAP) diaphragm. It’s a little tough to get to but can be done
with an offset Phillips screwdriver, it’s on the side of the carb nearest the
valve cover. Should fix you right up.