FloridaMan

The problem has been fixed. The purple wire was measured to have 12V with the key off. The white/black wire was verified to have 12V that was switched with the key. What I found was that the purple wire goes down to 7V with the key on. There was some kind of damage in the harness between the fuse/relay box and the 9 pin connector. Ran new wires for purple wire to the battery with an inline 5A fuse. Ever since then, it's been problem free *knocks on wood*.

View File MSU 500-700 Wiring Diagram THis is the wiring diagram for MSU500 through MSU700. It looks to be right and I have verified most of it by hand. Submitter FloridaMan Submitted 02/11/2024 Category Massimo  

I have a 2012 Massimo MSU 500 that died. I found that it didn't have spark and the fuel pump wouldn't run. Checked all fuses and none were blown. Went through and replaced the ignition coil, HT lead and spark plug. Still no spark. Thought it could be the fuse/relay box because I didnt' know much about the machine at that point so I replaced it. No spark. Then I replaced the ECM just because I was running out of ideas. No spark. I removed the 9 pin connector and hardwired it making sure that they were no wires got swapped. Still no spark. Then I replaced the wiring hardness. In doing so, I replaced the 9 pin connector with new ones. I made sure all wires were matched up between the engine harness side and the other harness assembly. Still no spark. I have no other ideas what to do. My fuel pump doesn't kick on and I have no spark. I have 12V on the fuel pump, ignition coil and fuel injector, but no ground from the ECM control. I unplugged the fuel injector and waited for a diagnostic code but nothing ever came in. It makes me think that the ECM isn't powering up. I've checked for 12V on pins 18 (purple wire) and 15 (white and black wire). I also checked for ground on pin 2 (black wire). All are good. I am out of options here and I have no idea what else it could be. I have all connections redone and are coated with dielectric grease. I've checked all easy things like fuses and making sure I have 12V in the right placed. I would appreciate any help.