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Chevy 1500 Pickup Engine Pinging
Q.
I have a 1992 Chevy 1500 full size truck with a new,as of last year, GM long block crate engine installed in it. The motor now has about 20,000 miles on it. The truck itself has 163,000 miles. The only thing that has bothered me about the new engine is that it pings. It seems to ping even when not under load and the transmission is in overdrive.
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It does ping more when under load, like towing my camp trailer, although it seems to ping somewhat all the time. The distributor and ECM are original parts. According to the manual I have, the distributor is an HEI type, although I have a remote coil and no vacuum advance unit. I believe that is what the ECM does.
I run 87 octane gas and keep up with the maintenance. I have replaced the knock sensor but nothing else, and still have the pinging. It never seems to be severe, but is almost always present. Do you have any idea what could be causing the constant pinging??? Any ideas/help would be appreciated.
Thanks,
Greg
A. The ping could be caused by running too hot, or a inoperative EGR system. The EGR valve and it's solenoid valve with all vacuum lines should be checked to make sure they are working as designed. A service manual will have all the diagnostic charts needed to check the EGR system out. This would be my first move.
This is assuming that the base ignition timing has been set properly to specs according to the emissions label under the hood.
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