engine pings on 1990 Toyota Pickup

My engine pings on light throttle loads. Not under heavy loads like full throttle. Timing is on etc. What could be wrong

by in San Jose, CA on October 22, 2010
2 answers
ANSWER by on October 22, 2010
check the egr system. that controls overheating in the cumbustion chamber which is the ping you here. Roy
ANSWER by on December 07, 2010
+1 on checking EGR. Pull the valve off, and check the small vacuum tube on the side of the EGR valve. It could be totally clogged up with gunk. If so, clean it out. Clean the rest of the inside of the valve as well, with carb cleaner. Make sure the spark plugs aren't too old, as that can cause ping. You can also try cleaning the combustion chamber deposits out, via fuel system cleaners. A good all-at-once cleaner to try is GM's Top Engine Clean. Make sure vacuum lines are all good, especially to the EGR valve and the EGR vacuum regulator. Make sure you have a stock or a 180 thermostat. Too cold or overheating can both end up causing ping.
Related Items:
Usually you can feel the transmission shift smoothly in the overdrive mode when you speed up.You have to really get the speed and RPM up to get the transmission to shift into the proper mode. The e...
ENGINE JUST STARTED PINGING AFTER I FILLED UP WITH CAS. COULD IT BE BAD GAS
I have a 1979 Toy pickup and need help, how many degrees off O is the timing mark. It is 4 wheel drive and has 22R fon the motor