1992 Mitsubishi 3000gt Runs Great Loses Fire Dies Wont Crank Until Wants

A bad crank sensor. Did you check for trouble codes?

It cranked an ran fine alllll day everywhere I went, cranked back no probs,, this morn, no go. No cel for 5 secs when inserting the key an powering up, also no spark. these two tbings seem to happen together..ecu maybe? Mfi relay, help lol !!!!!!

Have you checked for trouble codes?

Well, when I turn the key over, if the cel light comes on for the 5 secs,an goes out, then it starts an runs fine, no lights,no codes. Alot I turn the key no cel light at all, an no spark. Oh, an no code.

Such symptoms usualy indicates a faulty ECU. Remove the ECU and take off the cover to inspect the circuit board. If you see signs of leaking capacitors, that would be the cause of it.

Thank you, I have did that, looks brand new, I will try to find a known working ecu, an see what happens. Been in the shop two days an they cant get it to glitch :/ so ill keep updated,
Thank you

Looks can be deceiving as this is not a normal fault due to damage. It could be due to bad soldered joints. Look carefully at soldered joints and if you any that might look like the solder is cracked, try resoldering them and retest.