completely lost,no idea whats wrong.
 

i am ,as the title states completely lost. i am currently trying to get my 2000 gmc jimmy running and have no idea what could be wrong.When i first bought the vehicle i replaced the fuel pump then it still wouldn't start so then came cap and rotor after that i tested to see if i had spark,i had no spark so out came the distributor to replace it.

with new distributor in it still had no spark I had a friend hook up an OBII scan tool to it and the scan tool wouldnt come on so we tested it on another one of my vehicles and the tool worked fine.All of my gauges work when key is ON except the odometer gauge,all of my lights and other electronics work.

I have put new plug wires on as the ones before were badly corroded the old spark plugs are worn but should be capable of delivering a spark my friend said it could be the cars "computer" i have no idea what could cause the scan tool not to power on. i am completely stumped, (also the vehicle has about 150k on it the odometer has just recently stopped working i do not know what could have caused that.) any help/opinions/expertise is greatly appreciated.

Check fuses...
Also check the wires going to the coil...and possibly try a different coil.

Replace fuse for cigar lighter it protects obd circuit then you can get the scanner to work

Ensure the ECM has power first, then if the scanner still will not talk to it...then likely it is the ECM.

What is the history of this Blazer?