My 1984 Toyota pickup, 22R engine, pings every time I go uphill in the canyon I live in. Anything over about 1/3rd to 1/2 throttle will give me a lot of pinging. I can normally make it up the canyon in 4th gear at about 1/2-3/4 throttle and 35 mph, but to stop the pinging I go down to 3rd gear and drop the speed a bit.
I recently replaced the vac advance, the retard side was dead...and the timing is set according to the FSM, and total advance is around 30 degrees. The pinging is the same before and after replacing the vacuum advance. I also just cleaned out a plugged accelerator pump nozzle...no difference in pinging even though acceleration is a bit stronger.
Where else can I look...EGR system? Any suggestions?
jc
>>>*Personally, I like the engine to ping lightly at part throttle load if it goes away as more throttle is applied.
That is normally the point of best power/economy.
If the pinging just gets worse and becomes severe, something is wrong.
These engines are high compression and tight quench, so the source could be carbon buildup, a hot spot as a result, something like that.
The tricks are to try a slightly cooler spark plug, assure the EGR passages are open, loosen the valve lash slightly (.001 to .002" often does the job unless it then gets noisy), run a cooler thermostat (180?) or back the baseline timing off by a one or two degrees.
Sometimes spending a day at the drag strip is enough to blow the carbon out and fix the concern....*EB
