Mechanics

DIRTY INTAKE MANIFOLD

1986 Toyota Corolla

Engine Mechanical problem
1986 Toyota Corolla 4 cyl Two Wheel Drive Manual 140000 miles

I am currently replacing the combination intake/exhaust manifold gasket on my 1986 Toyota Corolla SR5 Carb'd.
I noticed that the intake manifold itself has a large amount of soft carbon build-up. Does this mean that the engine is heavily polluted as well? Should I dismantle the engine completely for a more thorough cleaning? I am currently trying to pass California smog testing.
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ISOD
April 22, 2008.




Usually carbon build up means a lean air and fuel mixer. That could be as simple as a O2 sensor. Or your carburetor could be out of adjustment.
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Tiny
Rob2008
Apr 22, 2008.
You bring to light something I don't know how to adjust and that's the carburetor. I have yet to fire this old engine back up, and I haven't replaced the old o2 sensor. I don't know if the o2 sensor is a recent replacement, as i've just gotten the car.

My main concern for many engines is the fact that the inside of intake manifolds get so crusty and sooty. Doesn't that mean some sort of putrification within the engine case? It probably does, so my next question is: what section of the engine block are likely to be dirtiest in a Toyota 4A-C 1986, or for any aging gas engine?

Tiny
ISOD
Apr 22, 2008.
I would say the dirtiest part in an aging engine block is the combustion camber. They make fuel additives that are supposed to clean it out easily or you could take the cylinder head off and inspect it.

Did the vehicle run when you received it?

Tiny
Rob2008
Apr 23, 2008.
This vehicle was running when I first received it. I am still in the process of cleaning out the manifold, and will inspect the combustion chamber next. Guaranteed 2 Pass cleaner from Kragen was used once on this car.

Tiny
ISOD
Apr 27, 2008.

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