Noise when accelerating

My car is 94 LE camry. It is closing to 180km. Noise used to be heard when accelerating or applying more gas. Someone told me switch to higher octane gasoline that will solve the problem. I had tried from 87 to 89, but it doesn't improved a lot. I can't always use high octane since gas price is not cheap. Can anyone tell me the best way to solve the problem or my engine have to be overhauled? Thanks

Which engine and describe the noise.

It is a 4 cyclinder engine and the noise like a bunch of key hitting with each other. There is no big difference with fuel consumption even with the noise. Thanks

It's called pinging, preignition, detination or engine knock. There can be many causes but, the EGR system and engine timing would be high on my list. Your factory manual in the "Factory Service Manual" thread at the top of the forum will explain how to test them. Ready to read? Here's more on the subject: http://www.misterfixit.com/deton.htm

I have heard pinging described as some BB's bouncing around inside a tin can. I have to agree with RIP. Check your ignition timing and also check the EGR system for carbon buildup in the valve and the EGR piping.

Mike

I forgot to tell you guys. The noise would not be heard when the engine was not hot. In the morning, the noise will be heard after 10 minutes of running on the road. If I stop the engine and let it cool down a little bit, the noise will disappear. At light time, the noise will be hard to heard, too. Also, the temperature gauge always showing good. What do you think? Thanks

"The noise would not be heard when the engine was not hot"

To me that's another indication of engine pinging.

Mike

"The noise would not be heard when the engine was not hot"

To me that's another indication of engine pinging.

Mike
Heavy pinning may destroy your engine. Premature detonation could even blow holes in your pistons. It needs to be addressed ASAP.

On my Subaru if I go a full throttle pinning will disappear. But who can drive full throttle all the time....

Sam

I think my EGR system is good as I pass the air care test. They is no big difference with the result comparing with 2 year ago. I think there must be the carbon deposit inside the chamber. I heard that Seafoam can remove carbon deposit. Do you think do? Please advice. Thanks

Seafoam is better used as a preventative treatment, as all fuel treatments are. It can help with light deposits, but a truly plugged or sticking EGR valve will need to be removed and cleaned or even replaced (not a cheap part!). Also, tend to the PCV valve, and then clean up the plugs, wires, and cap & rotor terminals as oxidation and build-up can cause rough idle and poor acceleration.

Does that means there is no solution to remove the carbon deposit other than overhauling the engine? Thanks.

Seafoam or a fine water spray mist into the intake manifold are the two most reputable ways of removing carbon deposits, but if the build-up is heavy, multiple treatments are necessary. Certainly not as laborious as a top-end teardown, but then not as thorough...anyone have better insight?

There are machines that decarbonize an engine. I have heard Click and Clack (the guys on public radio who do the Saturday morning call-in show "Car Talk") talk about them. They say they have one in their shop. I would call around to a few shops in your area and ask if they have a machine that can decarbonize an engine and what the cost would be.

Mike