Where is the knock sensor on a 4.3 v6 1995 astro van?

Answer 1

There are actually two knock sensors for the 1995 (one on the right and one on the left side of the engine block): Later model engines used a single knock sensor located on top rear of engine close to distributor At approximately 150K miles on my '95 Safari , my SERVICE ENGINE SOON light stayed on and the trouble code read was 43 indicating a problem with the ESC (electronic spark control) system which includes the knock sensors that are tied into the PCM. (The PCM either retards or advances the timing depending if the condition sensed is "knock" or "ping"). When first visually checked I only noticed the one sensor on the right side and set off for the dealer parts dept to buy a new one. There I was told there were two sensors but I decided to only replace the right one and see what happened...well I didnt luck out and the error code still indicated code 43. At this point I let the dealer service dept resolve the issue and they installed the second sensor. I received call that this still didnt take care of the error code and now I was facing a bad PCM as the possible faulty part. A new PCM was around $400 and to make matters worse...the existing PCM was a mongrel aftermarket type that had no residual "core" value which is worth about $100 if it's a genuine GM part. At this point I told the service dept to sit tight and give me a chance to locate another PCM. After a couple of calls to the boneyards I was told I could get one from a S-10 that would work for $50 if I pulled it myself. After seeing the S-10, I saw why it was such a deal since the truck had been rolled with the roof caved in...with all the broken winshield glass and the deadline to deliver the part to the dealer before they packed it up I managed to extract it from the wreck doing a few contorsions. In the end....the newly acquired PCM was sucessfully recycled after switching out the prom card. The Safari has been going strong ever since and no signs of the code 43 have resurfaced. In hindsight..there must be some way to check the sensors before just blindly replacing them in the process-of-elimination method but no useful suggestions were offered up by the dealer service dept as it seems they just read the same codes I did for their $79 "diagnostic evaluation" which was supposed to include some fancy trouble shooting equipment scans. Well live n learn....glad the problem was resolved....hope this info is useful to someone. Good luck!!!