Cat 40 pin ecm voltage to fire

Struggling to find an answer anywhere, I have a c12 in a 1997 ford aeromax. How many volts does this ecm need when cranking to fire? I have 12.4 on pin 4 and 6 with key on, but am down to 8.9 on those pins when cranking. Truck one day decided to crank and not start, speeds up a bit on ether, has 55psi for fuel, fuses and relays are good. Thanks!

 

Thank you very much for your reply! I found that the previous owner of this truck had spliced into the ECM wire from the batteries(for underglow lights lol) causing it to rot through completely and also rub and rot through the main heavy battery cable 3/4 of the way. So id imagine this ECM may have been damaged from that then as you mentioned with under 9voltsfor a long time. Fixed all the wiring and put on a reman ecm with still no start. I have a tech coming with Cat ET next week to look into it further and will post what the fix is hopefully. good chance this new ECM may also be a dud. Thanks!

 

Just to update what the fix was, replaced a lot of old damaged wiring with no change, also tried a reman ECM but had the same crank no start problem, both ECMS tested out fine, changed the cam position sensor as finally had it checked with cat ET and it showed 0 rpm while cranking. Truck instantly started up and runs with new cam sensor. Been quite the mess around but was also a good opportunity to fix up bad wiring along with better grounds and new fuel filters, primer pump etc.