Any advice on "Ping" issue?

[punisher]

Originally Posted By: BuickGN


Misfires make the sensor read rich which it tries to correct, making the normal cylinders go lean.



My line of reasoning:
A missfire (ignition missfire) will have raw hydrocarbons and air mixed together going out the exhaust. An O2 sensor measures exhaust O2 and nothing more, unburned hydrocarbons don't matter. Assuming no combustion takes place the exhaust O2 is very high as compared to a properly burned mix. O2 voltage production (in platinum sensors) is proportional to the delta between exhaust O2 and ambient O2.

Lean indications= low O2 voltage= high exhaust O2 content as there is not enough fuel present to use all of the O2 available.

Rich indication= high O2 voltage= low exhaust O2 content due to more fuel available to use the remaining O2.

Missfires jack up the available O2 in the exhaust for the O2 sensor to read. Higher O2 content in the exhaust equals a lean reading from the O2 which causes the PCM to richen the mix.

That's my story and I am stickin' to it.

 

[panthermike]

Originally Posted By: oldmaninsc
Originally Posted By: panthermike
Hey guys,

My girlfriend has a 2000 Corolla W/ 3spd Auto. It has 140K now but since around 100K has had a ping issue.

It is mostly on the freeway at around 60-70, sometimes not so bad and sometimes really bad.

Also, it seems it pings more in the summer time when it's hot?

Here are some things I've done to no avail:

Plugs(Twice), Air Filter, Cleaned MAF(Twice), Replaced PCV Valve, Multiple Fuel Treatments(Good ones), Seafoamed once a while back. Can't think of anything else right now.

Car has no codes, had some at 120K in which the cat and o2 sensors were replaced(reason I don't want to use seafoam again).

Does anybody have any ideas on what else could cause this ping?

Your advice is greatly appreciated.

Mike

Have you checked the cooling system? You said it seems to do it more in summer. Has the thermostat been replaced recently?


Yeah, I thought about that. Had Toyota Flush the system and replace the thermostat. It was slightly better but they also used an additive in the fuel, shortly after it returned to the usual. BTW, the car has always run cool.

That seems like a good idea to run SI-1 with 1/2 tank of fuel.

 

[BuickGN]

Originally Posted By: punisher
Originally Posted By: BuickGN


Misfires make the sensor read rich which it tries to correct, making the normal cylinders go lean.



My line of reasoning:
A missfire (ignition missfire) will have raw hydrocarbons and air mixed together going out the exhaust. An O2 sensor measures exhaust O2 and nothing more, unburned hydrocarbons don't matter. Assuming no combustion takes place the exhaust O2 is very high as compared to a properly burned mix. O2 voltage production (in platinum sensors) is proportional to the delta between exhaust O2 and ambient O2.

Lean indications= low O2 voltage= high exhaust O2 content as there is not enough fuel present to use all of the O2 available.

Rich indication= high O2 voltage= low exhaust O2 content due to more fuel available to use the remaining O2.

Missfires jack up the available O2 in the exhaust for the O2 sensor to read. Higher O2 content in the exhaust equals a lean reading from the O2 which causes the PCM to richen the mix.

That's my story and I am stickin' to it.


It's a chemical reaction with the hydrocarbons that produces the voltage from the sensor. That's why richer = higher voltage. I've seen it at the smog shop and on the dyno, a misfire makes it go off the charts rich.

 

[chevrofreak]

http://en.wikipedia.org/wiki/Oxygen_sensor

The smog shop was probably using a wide-band sensor that works different than a narrow-band sensor.

 

[punisher]

Originally Posted By: BuickGN


It's a chemical reaction with the hydrocarbons that produces the voltage from the sensor.


Nope, that's why its called an "O2 sensor".

 

[BuickGN]

Well that's great, we have now found a way to generate electricity from air. Sorry but it doesn't work that way.

And once again, an ignition misfire causes a super rich sensor reading. End of story. It's well known, I've seen it countless times. Do some more reading.

 

[Chris142]

Does this car have an EGR valve?

 

[oilboy123]

Auto-Rx got rid of my engine ping. Would not have ever thought it could do that.......

If I don't use a maintenance dose the ping starts to come back.
I tried everything to solve this and ran the RX just to clean the engine. But it solved the ping problem.

If you have never run it in her car it would be worth it just for the cleaning use of the product. If it solved the pinging that would be a bonus.

Good luck trying to chase down the cause. I did all kinds of things and had 3 dealers tell me they could not do anything about it.

 

[Anduril]

The 2002 Corolla I used to have pinged pretty much since it was new. Seems to just be something this engine does; mine tended to happen when I was cruising at a steady speed and go away when I stepped on the gas. Never did figure out the cause of it, though the car was a total POS in more ways than one.

 

[panthermike]

Originally Posted By: Anduril
The 2002 Corolla I used to have pinged pretty much since it was new. Seems to just be something this engine does; mine tended to happen when I was cruising at a steady speed and go away when I stepped on the gas. Never did figure out the cause of it, though the car was a total POS in more ways than one.


That's basically the way her car pings.

As far as ARX, it is in it's first rinse phase. And the car should have an EGR Valve, I would think so?

 

[Drew99GT]

We can stop with the timing adjustment suggestions - this car has coil packs - no distributor.

I would absolutely go to the EGR valve as the next step in diagnosis like Chris142 eludes to. These cars are known to consume oil and gum up the EGR port and the valve with carbon gook.

 

[panthermike]

Ok, EGR valve. I will get it checked.

BTW, I stopped by my mechanic's this morning to ask about the issue, he thinks it could be the Knock Sensor, but there is no code?

 

[panthermike]

I just looked at the online auto parts stores. None list a EGR Valve for a 2000 Corolla?

 

[panthermike]

Hey guys,

Just did some interesting reading over at toyota nation and some people are stating this issue on the corolla has to do with a faulty ring design(the ping as well as oil consumption).

If so, that kind of sucks, will just keep taking great care of the thing.

Also, they say these things don't have egr valves.

 

[Anduril]

Mine pinged and burned oil since it was new pretty much. Dealer thought it was something with the VVT (said I had a code for that or something) and replaced the head under warranty, which fixed the pinging for a VERY short time, but then it came back and never went away.

 

[Patman]

Does she drive the car very gently? If she doesn't go full throttle once in a while, my bet is on carbon buildup. I suggest you take it out and do a bunch of full throttle runs to clear out the carbon. I've been driving my Corvette pretty gentle this summer, with the high cost of gas, and it's been pinging a little bit at part throttle, so I took it out and did a whole bunch of full throttle blasts, and it's virtually eliminated the pinging now! (and it was fun to do the Italian tuneup!) I now make it a habit to make at least one full throttle blast from 40-90 mph per day, when pulling onto the highway.

 

[chevrofreak]

I've got to say, if full throttle blasts were all that was needed, my engine wouldn't have had a speck of carbon in it. I drive it like I stole it, but it still took some hot water through a vacuum hose to clean my pistons off.

 

[panthermike]

She does drive pretty gently but I drive it often and am not so easy on it.

 

[SHOZ]

Too much blowby will lower the effective octane rating if the fuel. On Fords there is a octane adjust plug that retards timing 2-3 degrees. Maybe the Corolla has one too.

 

[panthermike]

Originally Posted By: SHOZ
Too much blowby will lower the effective octane rating if the fuel. On Fords there is a octane adjust plug that retards timing 2-3 degrees. Maybe the Corolla has one too.


And that would possibly cause it to ping, is that you're saying.

Thanks.