Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
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Hi all.
I just completed doing a total tare down and reassembly on my 86 Iroc Z 305. Before I started the project I had a cooling problem, fans would not kick on until the car got to 230 deg. When this would happen, I would step on the gas and hear the pistons rattle and knock, service engine light came on. a code 42, knock sensor. I did replace everything that had to do with cooling and fan sensors and relays, even replaced the knock sensor. No fix.
So, for other reasons like OIL leaking problems , I tore the motor completely down. No engine mods were done Plane jane stock. Put a new thermostat, 186 deg and a new Temp switch 160 deg. Put the motor back together, fired up at the snap of the key, adjusted timing and drove it for the last few weeks. Fan kicks on at 223 deg, cools it to 210 deg and shuts off.
Drive it around the city and guess what "42 Electronic Spark Timing (EST) or Bypass Fault"
Take the module to an AutoZone and they can test it for this. And have them print out a troubleshooting guide for this fault if the module tests good. That is a very common problem, sometimes intermittent, and can be hard to find.
, I tore the motor completely down. No engine mods were done Plane jane stock. Put a new thermostat, 186 deg and a new Temp switch 160 deg. Put the motor back together, fired up at the snap of the key, adjusted timing and drove it for the last few weeks. Fan kicks on at 223 deg, cools it to 210 deg and shuts off. 
