Isuzu Repair: 94 Isuzu PU - no spark, ground wires, efi

Question
I have a 94 Isuzu PU w/ a 2.6 EFI.  Was running fine when I drove it into my garage . Pulled battery and did some body work and welding on frame.  Would not start after work - no spark.  Checked voltage and resistance at coil
( prim/second -- 4ZE1 engine)  Resistance iffy so replaced coil, condenser, battery etc. Receiving 12 error code from ECU/Diagnostics.  Truck has 89k on engine - no previous problems. Have not changed Pickup in distributor but may try. Any other thoughts.  

Answer
Check your negative and ground wires. That is the problem 99% of the time. Did you hit anything by mistake welding and short anything out. check you wires ion starter and alternator. what is the description for 12error code in your diagnostics part of owners manual? that should tell you right there at least what to start with. if I can find my old book I will look and see for youi.
Sorry I could not be of any help,
Derek