Complete Newbie at a loss... 97 8.0L won’t start
#11
according to the instructions the noid light would not have a constant power as the injectors do not have a constant spray, my understanding of the fuel system is limited. What I got from it though is that the injectors spray in time with the valves opening and closing on the block. This would give me the light flickering on and off in time with the engine cranking. Am I looking at things correctly or did I misunderstand something?
#12
Pretty much correct. When the ignition is on, it will engage the ASD relay for about three seconds, and then shut it off, until it sees the engine turning. (crank sensor) ASD supplies power to injectors, (always powered when engine is running/cranking, PCM controls ground side of the circuit.) and coil(s). Among other things. So, while the engine is cranking, you should see 12 volts TO the injector, and the noid light should flash a steady pattern.
#13
Pretty much correct. When the ignition is on, it will engage the ASD relay for about three seconds, and then shut it off, until it sees the engine turning. (crank sensor) ASD supplies power to injectors, (always powered when engine is running/cranking, PCM controls ground side of the circuit.) and coil(s). Among other things. So, while the engine is cranking, you should see 12 volts TO the injector, and the noid light should flash a steady pattern.
#14
#15
only thing I can think of is the gas station had bad gas... we filled it Friday night and drove a ton but never left it idle where it would have had a chance to pick up the separated gas/water mixture... parked it and let it warm up Saturday before heading out. Fell on its face within a half mile.. finally it had a chance to pick up enough of the water cause we weren’t driving(tank sloshing to mix). Some dry gas, injector cleaner, and fresh high octane fuel and it’s bad to its usual finicky self! Lesson learned, just glad we figured it out. My next step was gonna be to replace the PCM. With all the sensors and everything receiving the correct signal, I was next to assume that the signals then were not being read and translated for it to start!! On to fixing/replacing everything else on her, she was a very unloved plow truck.
#16
Thank you for throwing out suggestions and explaining some things in further depth. I am definitely a back yard mechanic with limited knowledge of the inner workings and tools used to diagnose issues. You were very helpful! I now have a couple new tools in the tool box and a trusty manual to look at if needed. By the time im done fixing her up I’ll be a pro!!
#17