Odd pinging issue
in stop and go driving for over a year. The hotter the engine gets the worse it gets. But it always stops at 1/4 throttle or if the coolant temp is below 200 or so. I've been scanning it carefully and its not running lean AND the computer does not pull any timing.Well after losing my mind trying to figure what is going on I FOUND IT. Its actually the lifters bleeding down too fast at high oil temps causing the valves to slam into their seats as piston comes up building pressure just before the valve closes causing the PING noise.
How I finally confirmed it was by driving it, getting it hot. Was "pinging" terribly then I added STP and its quiet as a mouse.
That a PAIN THE AZZ to figure out. If any of you have pinging and knocking without knock retard its your lifters bleeding down too fast.
The PCM won't KR because this noise happens BEFORE the spark event.
Drove me crazy for a year. I have to either replace the oil pump to get the pressure a little higher in traffic(38psi now) or run thicker oil or replace these crapo stock 01 lifters.
Any mods to your engine? Stock tune?
Russ Kemp





