How to fix pinging? -- SOLVED, additional info

I originally started a thread a while back in regards to a pinging problem in an 86 Cutlass Ciera. I used some suggestions (spraying
water thru the carb) which at the time fixed it for a while, but recently the problems came back. Today I did the next step which was replacing the EGR valve, which has completely fixed my pinging problem. In fact I have a suspicion that the EGR valve may have been bad for a while. However, I had seen some other posts before on testing the EGR valve on this car, and after changing one today I have found out that the EGR diaphram cannot be tested with a vacuum pump. The instructions with the new one also stated this. I do not know for sure why but these particular EGR valves do not hold a vacuum with a pump. I just thought I would provide this information, incase others are having similar problems , especially people trying to test the EGR valve itself.
Thanks, -- Chris
-- Original Post --
Thanks to all for the helpful info. I tried the old water through the carb trick, and it worked like magic. I did this about 2 weeks ago and the knocking has completely gone away. Just used an industrial spray bottle on stream setting and ran thru some distilled water with somebody holding down the throttle. Had to run a good 2 quarts of water through to get it to stop knocking though. Not sure if water can get mixed in with the oil so I changed it right after anyway to be safe.
Found lots of posts that say this works, so I'd like to back that up!
-- Chris (Chris Szilagyi) wrote in message

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