Pinging from engine compartment

I have a 1990 Tot Xcab, v6, 4"lift, 33 inch tires, K@N, Blah Blah Blah. I am hearing a pinging noise coming from the engine mainly on the HWY at 3000 RPM 60-70 MPH, mostly while the engine is under load, slight hill or accelerating. Other then that I do not hear it. The engine has aprox 170K, oil changed every 3500 miles. Dumped some BG44 in the tank as well as used there injector cleaner. Engine ran better but still hearing the pinging. Checked the timing and it is at 10 degrees as well as the idle is at 800. Any ideas why it is pinging and how I can fix it and in the long run can this damage my engine? Any comments would be greatly appreciated. Thanks JMach1

Reply to
JMach
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sounds to me like a vacuum leak.. Check your intake plumbing first.. clamps, hoses, etc.

Once, I tried to start my car and I heard a backfire.... It wouldn't start again. I lifted the hood and a hose had blown off the intake. I replaced it and the car started and ran better than it had in a long time...

Reply to
Celica Dude

Reply to
JMach

Well, if it hasn't been doing this in the past, your knock sensor may no longer be doing its thing. Chances are that it is the pigtail connecting the sensor to the wiring harness that has given up the ghost. This is quite common on these motors. A new pigtail is available from the dealer for ~ $15. Unfortunately, it is a heck of a long ways in to replace the thing. It sits on top of your block, meaning the intake manifold must be pulled to replace it.

If you want the quick and dirty solution, try retarding your timing a couple of degrees. You will lose a bit of power, but it will get rid of the engine knock and won't hurt anything. You may have to up your idle speed (800 is spot on) if you back off on the timing - all you have to do is turn the big screw on the top front of the throttle body to adjust the speed.

Luther

Reply to
Luther

Reply to
JMach

Turn the distributor in the direction that causes the motor to slow down. That will be retarding the ignition or moving it closer to TDC. I think you said the timing is currently correct - in that range, it will be obvious as hell which was is which.

Luther

Reply to
Luther

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