Pinging like crazy

[BD29]

I bought some throttle body/air intake cleaner and decided to clean my throttle body. First I read the can and it said to "use liberaly." I probably used half of the can while cleaning my throttle body. After letting it dry out for a few minutes I reinstalled the intake hose and attempted to start my truck. It would not start immediately but from what I've heard that's normal after spraying in there. It eventually started and idled rough for a few minutes. After the idle seemed to smooth, I drove it. From that point on my truck started pinging like crazy. The first thing I did was take it to one of the Toyota dealers here in town. They told me that I need an engine overhaul and charged me $150.00 for their theory. Prior to spraying the intake cleaner, I had no engine trouble whatsoever, so I find it hard to believe that I need an engine overhaul. I have been hesitant to take it to any mechanics since then. I can control the pinging by running 93 octane and adding some NOS octane booster but I don't want to drive my truck like this forever. If anyone could help me diagnose this problem it would be greatly appreciated. It is a 1992 four cylinder (22RE) pick-up

[KimMG]

Did you check the timing?
Do a compression check.
Let us know what the spark plugs look like.
Are you using much oil?
Is it running hot?
Are you losing coolant?
How's the fuel economy?
Some additives/cleaners ruin O2 sensors and affect the air/fuel ratio.
Why exactly did the shop say your motor is bad? Did they provide the results of any tests they performed?
Other than pinging, are you having any other problems? Does it run smooth and accelerate well with the higher octane fuel and additive?

[BD29]

Originally Posted by KimMG

Did you check the timing?
Do a compression check.
Let us know what the spark plugs look like.
Are you using much oil?
Is it running hot?
Are you losing coolant?
How's the fuel economy?
Some additives/cleaners ruin O2 sensors and affect the air/fuel ratio.
Why exactly did the shop say your motor is bad? Did they provide the results of any tests they performed?
Other than pinging, are you having any other problems? Does it run smooth and accelerate well with the higher octane fuel and additive?

I don't own a timing light so I have'nt checked the timing. I never had a pinging problem before so I figured that my timing must have been on. I am not using alot of oil at all. I would say that I might have to add about a half of a quart in between oil changes. I am not losing any coolant. My fuel economy is great! I'm getting somewhere in the mid to high 20's in town and over thirty on the highway. I run nothing but N.G.K. plugs and I usually change them before I ever have a problem. The plugs are always wearing normal according to my Hane's manual. I am leaning toward a sensor problem
and I told Toyota that's what I thought it was. I asked them to check the codes but I was never given any results. The only thing I was told was that
"you need an engine overhaul." I was also told that they adjusted my timing a little. They were extremely vague and I was very dissapointed with their service. The small adjustment they made to my timing did'nt make a difference whatsoever. As far as performance goes, my truck runs great. It accelerates smoothly and seems very strong. The engine has 140,000 on it but it has been maintained excellent. This is my second Toyota truck with a 22RE. My first was totalled. It was such a good truck that I went out and bought another one just like it. Do you think that I should start by putting a new O2 sensor in it? I hope that I answered your questions good enough. Thank's for your help.

[KimMG]

Do the plugs look white, black, or tan now? If the timing is too far advanced, pinging will occur. You need to check the timing. Have you adjusted the valves?
140,000 miles is almost like new (mine has 170k and runs great). Since the dealer did not provide detailed results of the diagnostic testing, I believe the dealer is trying to rip you off.
Some autoparts stores rent specialty tools. autozone.com has online repair manuals that may have instructions on how to test your O2 sensor, retrieve codes from the computer and how to adjust the timing. Check out the top thread on this board. There is a factory service manual available online for your pickup.

[GDBSKE]

Pull the O2 sensor out and see if it has junk on it, clean and put back in, see if that helps. If the sensor gets covered, it won't see oxygen, thinks engine must be rich and leans it out. Causes pinging. Based on what you did to cause the problem, that sounds most probable to me.
If you pull a plug it will be white if the engine is running lean. That would be an easy check.

[BD29]

Thank you guys for your excellent advice. Now that I understand how an o2 sensor works, I'd be willing to bet that that's the problem. Alot of blowby was coming out of my throttle body when I was cleaning it and it makes sense that it could have covered the sensor. I hope to take the sensor out and check it this weekend. I will also take a look at my plugs. I could be mistaking white for tan. I will post again after checking the sensor.

Thanks,

BD29