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1990 Corolla Pinging

By Guest harrism, March 13, 2009 in Pre-1997 Toyota Corolla and Geo Prizm

Guest harrism

Hello, I have a 1990 toyota corolla with a first gen. 4a-fe engine. Unfortunately within the past 5000 miles or so the car has started pinging when under load (ie going up a hill). The engine has 170,000 on it and according to the original owner, it has never been touched. Someone suggested give it high octane fuel, so I purchased octane booster which had no effect on the pinging issue, another person suggested I check the oil. It can't be the oil because I always make sure theres an ample amount of oil because it has a leak which I suspect is because of the valve cover gasket which brings me to my next suggestion, should i replace the valve cover gasket? Three of the four spark plugs have oil filling up in them (some varying worse than others). Is it possible that the oil in these cavities is fouling the spark plugs, causing detonation?

FYI - I don't think its carbon buildup either because the previous owner had the fuel injectors cleaned some 20000 miles ago.

Any thoughts appreciated, thanks in advanc.....

edit: *also, she runs a little rough when idling, not consistently. it'll run smooth and then it feels like its about to stall but catches itself.

High octane fuel booster doesn't do a whole lot - actually cheaper to fill it up with premium. Boosters usually push fuel up 7 to 10 points, not octane number - this means if you filled up with 87 and added a bottle of 10 point octane booster - you would end up with 88 octane gas.

Try it with premium and see what happens. You could still have carbon buildup on the tops of the pistons - so a fuel injector service might only fix half of the potential issue. Double check the plugs, plugs wires, and cap & rotor - make sure they are all sound. Usually checks, vacuum leaks, PCV valve, maybe give the throttle body a good cleaning. The plug wells filling with oil could very well be sapping power from the plugs, resulting in misfires. I'm pretty sure the 4AFE had little rubber gaskets around the plug wells - probably not a bad idea to go ahead and pull the valvecover to replace those o-rings. Also lets you get a good look at the valvetrain.

i'd suggest trying a seafoam topend cleaning, my mothers 97 Mazda 626 was getting some pinging up hills and seafoam cleared the problem up for her and its been gone for the past 2 years.

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