Re: Corolla Rough Idle After Timing Belt Change


"SlyckTom" <tom@xxxxxxxxx> wrote in message
news:jl4cf2td91rn8kij1aj8nor3mee8co9jet@xxxxxxxxxx
How low is low? What is idle RPM when the engine is cold and when it is
warmed up?

This is hard to tell, since I dont have an RPM gauge. But I can tell
you that it idles slightly better when warm than cold.

Are you talking about camshaft timing or ignition timing? Were the
camshaft
timing marke aligned perfectly AFTER reassembly? A poorly running engine
is a symptom of one of the camshafts off by a tooth.

I am talking about both the camshaft and ignition timing. And yes,
they were both aligned after reassembly. I would understand if it was
off by a tooth if the engine performace was terrible, but it is not
once I am out of idle. In fact once Im driving it runs better than
ever.


Yup, that seems to rule out a mis-timed camshaft.

Disconect the vacuum hose to the EGR valve and plug the disconnected
vacuum
hose with your finger and see if the condition clears up. If it does not,
re-connect the EGR.

No EGR valve on this model...

See if you can measure manifold vacuum. You should have above 16 in Hg at
idle.

Manifold vacuum is on the money.

But here is some progress that I have made:

I reset the computer, and the car idles somewhat better - not perfect
but not nearly as poor as before.

Also, and this may be the first real sign of progress, if I disconnect
the Throttle Position Sensor, the car idles perfectly.

Another point I should make...I gave the engine a good power washing
after the job, and in the process appear to have made an exhaust
manifold gasket leak worse (cleaned eons of oil reside out). I wonder
if the introduction of air towards the O2 sensor perhaps is throwing
something off?

Thank you again,

TOm


I doubt if the O2 sensor is causing the rough idle.

Does the car have an idle air control valve and if it does, have you checked
it out?


--

Ray O
(correct punctuation to reply)


.

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