no cel when starting

when i switched key the on position the cel doesnt come on at all, even when i jump the diagnostic mode plug it doesnt come on either. i know ther blub inst burnt cuz the cel comes on when i disconnected the speedo cable. and sometimes i have trouble with no crank issue and cranking but no start issue too is there something ground related or bad connection or something? the main relay looks great no cracks at all. these issue drives me insanely nuts lol

there is a ground cluster on the thermostat housing. check/clean that. also, check the B/U fuse
if both are good, check your power and ground pins at the ecm. should be 2 power pins, one constant and one keyed. also, check the ecm grounds. should be 3, i believe

B/U? and what u mean wires on ecu ? i wouldnt know what to look at lol but i would love to snap a picture cuz they have been jack rigged before by previous owner (forgot about that)

you need a pin out diagram for your ecm. find the ecm grounds and powers on the diagram and check them at the ecm. there should be 2 power pins. one constant, and one keyed. the B/U radio fuse supplies power to the constant pin. the technical term for the pin is KAM (keep alive memory). but first, check the B/U radio fuse, usually under hood. this fuse supplies power to the ecm KAM, radio (for things like presets), and clock memory. basically everything that needs power when the vehicle is off. does your clock keep memory with the key off? does the radio keep it’s presets? since the car runs, i doubt it’s an issue with the ground cluster at the thermostat housing. but check/clean it anyways

if you’ve got hack spliced crap on the KAM circuit, it’s possible that it may have either shorted and blew the fuse, or the connection is broken

The back up fuse it should be a 7.5 amp fuse under the hood may also be labeled ecu