1990 Toyota Corolla



May, 24, 2009 AT 5:50 AM

Engine Performance problem
1990 Toyota Corolla 4 cyl Front Wheel Drive Manual 125000 miles


I'm sentimental with my car, named her Sophia, and I would not replace her for as long as she runs and I intend to keep her running.

I'm planning several upgrades to squeeze more horsepower out of an old, 20years old car. But I ran into some problems, please allow me to explain.

Carburetor: I want to upgrade to a a cold air intake system but I can't find an air intake manifold with 2 bleed ports for air. My engine has an air bleed port, I don't want to shut it off. Any suggestions?

Distributor: My distributor's running fine but there's an oil leak coming from the shaft, I've been changing oil seals every week, I think the shaft's off, but the engine is running smooth. Any idea?

Spark plugs: What do you recommend for spark plugs? Heat range and gap standards? Should I go for multiple points and high heat range plugs?

That should do for now, I hope I'm not asking too much. Please help, I need experts to guide me. I want to learn how to do it so that mechanics here cannot knock me off. LOL!

Thanks and best regards,

Jack Olson


Vacuum Leak


20 Answers



May, 24, 2009 AT 7:47 AM

Cold air intakes really do not do much for an engine in terms of horspower, they look good, but it is hard to beat the factory system. Most that are constructed out of aluminum actually conduct more heat and raise incoming air temps. A K& N filter would flow more freely, but they ain't cheap.

If dist. O ring is leaking, get a new one from Toyota, if you suspect shaft is worn, replace dist. With a rebuilt unit with module. It is actually cheaper to put the rebuilt unit in than the module itself.

Denso has a new plug on the market called " TT" Twin tip, very affordable and a very good plug.

The only way to make more horsepower is to get more air into engine, this is usually done in one of three ways, Nitrous Oxide, supercharger, turbocharger. All of which are expensive and you must be carefull about increasing cylinder pressure on a 19 year old engine with 125K on the clock.

Instead, keep the engine it top tune, replace plugs, wires, dist. (As mentioned above), carb rebuild kit.
If car is smoking on startup, change valve stem seals.

If you are really adventurous, remove head, valves, intake manifold, have head and intake hot tanked and cleaned, check valve guide clearence, replace seals and any guides that are bad. Re-shim the lifters to factory specs. Check all sensors, change trans. Fluid.



May, 25, 2009 AT 1:37 AM

Thanks for the great reply.

I'm dumping the idea of the cold air intake, instead I will maintain my stock air intake and rebuild my carb. I have a question though, can I use any heat shield to keep my air intake manifold cold?

With the O rings, I think I will have to look deeper into the shaft and replace the whole distributor block, I have a new rotor and cap but I guess I have to wait til I get the new dist.

I'm buying a turbo and maybe add headers maybe a 4-2-1. Do you have any better suggestion? I was thinking of a one-off header mod, imagine this, put a separate header for one cylinder so in all I will have 4 separate header pipes, I can get 4 cats and 4 mufflers. Or no mufflers i'm gonna use just a downpipe instead. What do you think?

And yes, i'm thinking of a top overhaul. Folks here does not recommend a general overhaul, all they tell me is to buy a new engine. Then I guess I have to grease up my hands all alone.

Thanks and more power to you.




May, 25, 2009 AT 7:21 AM

Probably the best idea is to wrap the intake tube on the factory tube with an insulation tape, a company called "DEI" makes a silver tape that insulates from heat.

I think I have seen headers for the 4AFE and 4AGE engine.
The 4AGE is the high performance version, it puts out 130hp as opposed to the 102 on the 4AFE.
Changing would be pretty straightfoward, but the wiring would be a difficult, major difference is the head.

Turbos are generally straightfoward installs, but YOU MUST reprogram the ECM and upgrade MAP sensor (2- BAR) to add more fuel to the engine or you will very quickly burn the engine up by running it lean.

You may be better off going to an FI engine from a 90-92 Corolla, get engine and wiring harness.
Lot of work, but fun to do.



June, 2, 2009 AT 2:11 AM

Thanks for the kind help and for the pic

right now i'm trying to improvise on an air intake, try to see if it will work

instead of buying a kit, i'm running a hard rubber pipe fitted with a filter I made out of the stock filter, it's still on the drawing board though.

I have a question bout the pipe: will it matter to have a longer pipe or a short one? Will it be better to keep the pipe straight as possible (less bends)?

I'm also looking at making a scoop-like mod on my hood so that the air can slam into the filter

what'd you think?

Thanks and more power




June, 2, 2009 AT 6:20 AM

Keep tube straight as possible. Bends should be mandrel bends.

Ironically, I did see a turbo kit on the internet the other day, but dog-gonnet, I can't remember the name of the co. That sells it.
Had turbo, intercooler, reprogrammed ECM, new exhaust, all bolts, hardware. I think it was around $3800.
Google " Toyota Turbochargers".

You could also investigate Nitrous Oxide, maybe a 35hp shot. If nitrous is your choice, have it tuned on a chassis dyno to get proper A/F ratio.

Another possibility is finding a 4AGE engine and complete harness, you would also have to change fuel pump to FI pump. As mentioned the 4AGE puts out 30 more HP than the stock 4AFE.

Go to local drag strip and see if there are any Toyota's there, talk to owner. They would probably have a lot of info on swaps, HP increases.

Remember, " the only substitute for cubic inches is cubic dollars : ).



June, 3, 2009 AT 2:07 AM


LOL! Very well said with the inches and dollars. Thanks for the support. I'm afraid there's not much drag strip here in the Philippines to check with and most guys here owns a Honda or something else. The locals here who owns Toyota are either keeping them stock as possible or getting another car for hyper tuning. Anyway, I'll google my way into it and hope that I don't end up getting one of those Hondas, LOL!

I'm tempted by that 4AGE, I'm eying this one Black Top from a contact but if I'll get it, I wonder if I can modify my Toyota to a 4-wheel drive. Sounds crazy though.

What do you think? Get a new engine with new transmission and all, I'm just gonna keep the chassis and body for Christ sake.

I'm not into NOS and supercharges. I prefer TURBO more.

Again, thanks for the wonderful help. More power.




June, 20, 2009 AT 6:36 AM

Hi guys,

I have a 4A carb-engine in my toyota. Is it true that Unleaded Gas with E10 is not safe for carb engines? I've been using unleaded petrol until the E10 additive came out, so I switched to using Leaded Gas. Here in my country I'm using Petron XCS gas or sometimes even higher octane premium gas like Petron Blaze or Shell V-Power. Will this affect my old engine?

Thanks and more power!




June, 20, 2009 AT 7:54 AM

Almost all engines built since the early 80's are designed to run on 10% Ethanol (NOT METHANOL).

If you have a convertor the lead will destroy the O2 sensors and convertor.



June, 21, 2009 AT 5:29 AM

Thanks for the reminder.
I do have a catalytic converter but I'm not sure if my engine has an O2 sensor, I think it's just for FI engines. Gas stations here are saying that E10 fuels are not recommended for carburetor engine.

BTW, would you choose synthetic oil over other kinds of oil? Which would you recommend? I'm changing my oil and gear oil next month.

Thanks and more power.




June, 21, 2009 AT 8:40 AM

Your owners manual should tell you if you can run E10.

But generally carb engines can run it.

Synthetic oils have a lower coeffecient of friction, are highly detergent and can withstand much more heat than conventional.

Mobil 1, Royal Purple, Castrol Edge are all good synthetics.

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