I am replacing a 4.3 engine in a 1996 chevy c1500 for my son in law. I got a long block from GMPM. There are several electronic components on the engine that I do not really know the function of. Can you folks suggest which sensors, etc. I should probably replace during this engine replacement? I have replaced the injection spider and fuel tank fuel pump. The truck It had poor and inconsistent compression, lack of power and smoked, but otherwise the truck started and ran reliably before the engine was pulled. Also, what sealant, if any should I use on the o-ring type gaskets that many of the bolt-on components use?

Thank you,
*****

 

If you’re still needing an answer….

As long as the sensors are in good condition (casings aren’t damaged, wiring & connector in tact), there’s no need to replace them. Just spray some brake cleaner on a rag and wipe them down.

Solenoids - such as IAC, EGR and AIR injection - should be tested for functionality and only replaced if necessary. If good, clean off any carbon buildup with brake cleaner and compressed air.

Replace the O-rings as needed. There’s no need to add sealants but a light coating of grease will help them seat.

 

Thank you very much for your response. This is very helpful.

Best Regards,
*****