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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.

Massimo 500 will only crank when I jump solenoid with screwdriver cranks right up and runs great. But won’t start with key doesn’t do anything when I turn the key. Only thing it does is power everything as in dash and fuel pump then have to jump solenoid to crank up and drive.

Hello everyone, any help/advice would be greatly appreciated. Helping my father with his 2018 massimo 500 4x4 side by side. He uses it to feed all the horses and cattle. As of now the only way I can get the dang thing to start is to take the fuel injector and hold it about a inch away from the head boot, start turning it over and as it starts up I just press the injector all the way in. I thought this was a air problem so I replaced the idle air valve. I also replaced the fuel injector, spark plug, and adjusted the valves not that long ago. I thru a new computer on it as we had a extra on hand. It is running pretty good just won't start without that trick. Does anyone have any ideals what the problem may be?

My Massimo 500 will not start. I’ve checked all the obvious things. It turns over just fine. fuel, spark, fuse box are all good. I can’t figure it out. Any ideas would be greatly appreciated. Thank you.

Have Massimo 500 .ran fine. Got new front tire.now it pulls to the right and feels like brakes are dragging.searched online, did string text to align.what can I do to correct this? Tx in advance for help.

I have a 2017 500 Massimo that is weak like will not spin a tire in a good mud hole. Does anyone know how to boost power. A friend told me of a chip to bypass emissions. Has anyone tried the chip or have a suggestion. Thanks in advance.

I have a 2021 Massimo T-Boss 550. It was submerged in water for a period (hurricane). All filters/fluids were drained and replaced/refilled immediately after as well as air box cleaned. Drained fuel tank, popped the supply line off and key cycled to clear the line of contamination. Reconnected line and filled with fresh fuel. The machine fired and sputtered for maybe 30 seconds and died. Upon attempting restart I noted the fuel pump wasn’t priming. I checked voltage at the pump and it is 12v. I’ve replaced the coil pack, wire, ecu, ignition (which was failing just prior to the water event) and the fuel pump. The new pump still does not engage. Rechecked with new pump and there is 12v at the plug on top of the tank as well as down at the pump. I’ve popped apart all the plugs I can see, sprayed them with terminal cleaner and applied dielectric grease. Still nothing. I’ve talked to a buddy and he has said it has to be a connection or ground issue. Anyone able to point me to specific plugs wires etc to check? I’m paying for the answer. 😂

We have a massimo 500 utv we have changed the fuel pump (but you can't hear it kick on) we put a new fuel injector on and a new plug the thing will turn over when trying to start it but it will never really start or run. Can poor gas right down the throttle body and it will run for just a second and stop please help. Not sure what else could be the cause of it not wanting to start and run

At random times it completely loses all power to dash and won't start or cuts off. I've checked all fuses and power/ground to battery.

Hey everyone. This is my first post and I hope you all can help out here. I have a 2016 Massimo 500. I'll start out with "it is a beast" I have worked the crap out of this thing and it keeps on coming back for more. Never had an issue except one battery replacement and this cold starting thing. When I start it up, summer or winter, it requires being in neutral, pre-loadiung the fuel by pumping the gas pedal (like an older carb model) and then once it starts, I have to maintain 3000 RPMs or more for at least three or four minutes before it will idle on it's own. After that, it will idle for as long as you ask it to. Any input?

Have a 2017 missimo 500 won’t idle seams to be running rich new injector fuel pump new air filter what else would it take .

I don't use my 2012 500UTV a lot. Occasional yard work and plowing snow. I noticed cooling fan was not cycling as normal, wasn't coming on at all. Overflow reservoir was dry so I added. Pulled the connector at the sensor on the rad and jumped a wire across the terminals, turned on key and fan working, so I figured bad sensor. Replaced sensor and fan still doesn't come on. Radiator is full to the top. I started it cold and let it idle so I could monitor. The coolant hoses get hard from pressure and radiator gets hot. It gets too hot to touch for more than a few seconds so (I assume) coolant has to be circulating, but no fan. I have no problem replacing parts but I have no idea where to go next. When I do use it I can tell from the heat coming through the cover that it's getting hot so after a short while of use I park it. I'm considering running the fan with a toggle switch but that's rigging, not fixing. Don't know if this is related but even with a perfect battery it labors on the starter. On and off the starter a few times and it fires up. Any advice I can get will be appreciated.

Massimo 500 wont start. Pulled the injector and when i turn the key it sprays a lot of fuel, but the spark plug is dry. What would be my next step? Valve adjustment?

I have a MSU 500 and sometimes it acts sluggish in 4x4 and you can smell hot gear oil. I'm Thinking it is something binding up the the transfer case or front differential but before I dig into it I wanted to see if anybody had a similar problem. Thanks,

I have a 2015 Massimo 500 that idles really high and it will not let me shift into gear while it's idling. Not sure where to start. Also it will bog down and stall constantly. Starts right back up everytime. Advice please.