Mcx NYTRO BLOWING IGNITION AND/OR 40 A MAIN FUSE

[Washy]

IT seems to happen when running the sled for about 5-10 minutes. After running it hard back and forth in the feild it will pop the fuse either one or the other. I ran the sled out of gas once last year and that is when it started blowing the ignition fuse. Now it will either blow the ignition fuse or the main fuse. What do you think. I replaced the fuel filter and still pops fuse. I am thinking it is the MCXpress external fuel pump but looking for suggestion. All connection dielectric greased and no moisture anywhere. Not enough snow for moisture.
After replaceing the blow fuses it runs perfect, until I run it hard back and forth in the feild.

I looked for any wires chaffing on underneath the handle bars, seems good. and cant see anything chaffing on the clutch side where the wires run along the inside of the bulkhead.

 

[zebiraross]

Grrr! I hate electrical problems. Sorry I don't have any ideas.

 

[SPOOLED]

fuse blown, lets see, amperage increase? bad ground check and see if the ground onto the block is loose, or battery cables loose. bad connections increase amperage.

 

[SLY]

The fuse has to be changed to a 25 or 30 when using the external pump, or else it will blow as soon as you put a good load on. If you already did that, I would try a filter, then a pump

 

[TTE]

If not done yet - I would add a seperate realy and a 30 amp fuse just to the fuel pump to make sure it got enough power. As said check all wires.

I had the same problem on the RX-1. I had the fuel pump hocked to the ignition fuse and fuse would blow under load. After installing a seprate relay directly from the battery with a inline 30 amp fuse just to the fuel pump the problem was gone.

Hope you get her fixed

 

[Washy]

The fuse has to be changed to a 25 or 30 when using the external pump, or else it will blow as soon as you put a good load on. If you already did that, I would try a filter, then a pump

Already had the 30 Amp fuse in the ignition holder, it blew the 30. I talked to your mechanic yesterday SLY. Though I would give him a call before I brought you the sled. He suggested the same as you, so I changed the fuel filter, and still blew the Main and ignition fuse. Checked the battery grounds and chassis grounds, still blew the fuses.

I have a new pump so I will try that.

 

[Tuesday]

With so many miles on your sled and running the same kit throughout my thoughts are the same as above. Either a bad ground or something is drawing to much load (ie. bad fuel pump). Last year I was talking to the guys at PG yami in BC and they where trying to tell me that the fuel pump should be replaced every year because it is prone to dying.......I called BS on that but maybe there is some truth to it.

Let us know.

 

[Washy]

I was leaning towards the fuel pump because I did run it out of fuel. The next day I blew a fuse for the first time. Season was over after that, so kind of forgot about the fuse blowing issue. I ran My trans am out of fuel back in the day and the intank electic pump crapped out the next day. Apparently they dont like being run Dry. Crossing my fingers. Old pump was 2 years old and 4500 kms on it, it did seem to whine when it was running, new pump does not.

 

[LOKI]

Check wiring harness on front left hand corner of engine. Harness will rub against engine and cause fuse to blow. Have seen multiple 2008"s do this.

 

[NM]

Check wiring harness on front left hand corner of engine. Harness will rub against engine and cause fuse to blow. Have seen multiple 2008"s do this.

I had the fuse blow issue and traced everything back but found nothing. When I reinstalled the harness I made sure it was strapped away from the motor and never had an issue again. I also added a heavy ground wire from motor to chassis because I had to do it to my Apex. It probably never made a difference but it's there now.

 

[SLY]

The pump is also lubricated by the fuel. If you ran it dry, it whines and has 4500k, I would try another pump if you have one. We use different pumps for replacement. Changing that filter regularly will also help with pump life as the pump will not be working as hard, have seen a few restricted filters.

 

[LOKI]

did you fix your problem yet ? what was it ?

 

[Pastor]

I blew that fuse 40 amp once. I had left the key on all night and ran my battery totally dead.

In a hurry I switched the pos and neg when I jumped it and had to make a substitute fuse with a 35 amp that I stuffed inside the big 40 for the day.

I would guess that it is either the fuel pump drawing too much because it was damaged by running out of fuel or while you are bouncing along going back and forth in the field a wire is bouncing a round and touching something and blowing the fuse.

Electrical problems are really tough.

 

[Washy]

did you fix your problem yet ? what was it ?

Yep took it to Slave Lake Yamaha and they found the problem very quick. I could not get it to pop anyfuses, they succeeded. Wire on the front left side of the motor as you said worn right through. Burnt and black. They are fixing it now. It was rubbing on the nub on the front of the Engine.

Thanks Guys for the help.