Blown Fuse

[ratsracung6]

Hello everybody new on here my son just bought a 09DS450 Mx
about a month ago. We had a little problem this weekend.
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Well went and praticed sun my son made 3 different runs of about 6 laps each. On the 4th run he did 2 1/2 laps and the quad died would not start back up. pull it back to the truck and let it cool off thought it may have went in to limp mode. After it cooled off it still would not start, the neutral light would stay on even in gear and the check engine would flicker. WTF!!
So we stated checking connectors all good, checked fuses 1 was blown.
Replaced the fuse and it ran fine did 5 more laps all good.
We got back late last night so I did not get a chance to look and what the fuse was for but looking at the wire diagram it was a 15 amp fuse and the diagram only has 1- 15amp and its the injector/ignition fuse. anyone have a problem like this. I will look tonight and see what wires lead to that fuse to make sure thats what it is.


Thanks Scott

[TNT]

First off the limp mode won't shut the quad down, it "limps' certain engine functions at a certain engine temp so you can still run without burning something up. Loosing fuel pump power DEFINITELY will!

I'm guess somethings is shorting out between your battery/stator and fuel pump blowing a fuse...No not common check all wires for a loose connection.

[ratsracung6]

Ok I checked last night all connections are good, wiring looks good
no kinks anywhere. tnt you posted about blowing fuses on the
08 which ones were they blowing.

Also could the gas getting hot cause that fuse to blow? Just trying
to check all possibilities, it happened going into a corner I just
want to try and find out what it is so it dont do it again, it would not be pretty if it did it on a jump.

[TNT]

09 fuses are good!

When you turn your key on the pump should cycle on for a few seconds to build pressure in the sys, try this several times, go ride it down the street stop rest and try again. Did you check your case grounds, if I remember right the are on the right side engine?....The pump harness needs a chassis ground.

You can check this circuit at the pump connector by doing a resistance check from the outer pin 4(looking at the female connector tab down, far left pin) to the chassis…..you should also get battery voltage between pin 4 and the ground pin next to it 3…... After a few secs the voltage there will drop to 6vdc, that means the ECM is grounding and working and shutting the pump on and off. Unplug your ECM and plug in back in, make sure all pins are intact and make contact, the pump also needs a ground to the ECM.

Do the voltage check first pin 3-4, if no battery power then check pin 4 to the chassis. If you get nothing then it's the relay, fuel pump windings, or something else going out.

Let me know what you find, BUDDS(dealer software) and a diagnostic code may be your best shot.

Fuel pump boiling won't cuase this there is no thermocouple in the circuit. I got a new CV 4 tank boot for the DS being mailed now, all new technology better than heat tape. I'll post some photos soon.

[TNT]

Other thing you can try to eliminate it is up front of the radiator there is a series of three rectangular white relays, swap the outers, the cooling fan and pump, then go test ride it and see if the fuse still blows. Don't touch the middle ECM relay.

[ratsracung6]

No its running fine now and has been since replacing the fuse.

[TNT]

Its not running fine if a blew a fuse for no reason. I'd have it thoroughly checked out completely myself or by the dealer, BUDDS! Before my kid raced it again. But thats your call. Good luck! :D

[ratsracung6]

Im not saying its fixed. Im just trying to look at all possibilities,
prob end up taking to the dealer and put on the BUDDS.

Thanks for all the help Terry. Are you racing N40 this weekend?

[TNT]

I wish, just racing local on the dang YAM! Looks like it may rain here again. I'd drive down there but our luck with the YAM no good lately and Im really loosing my patience with CP and the DS custom piston we had made taking forever! I did hear the Fuel Custom intake we had made is in, I'll get some photos soon as get to the shop.

How about you going? Hoping to make Oak Hill on the DS.

[ratsracung6]

Yes we will be there N40 is local for us 30min from the house.
Our Yamaha will be with us to but with a 4 sale sign on it.

do you still have the axle for the yfz if so I might have someone
that might want it?

[TNT]

Ill have a 4-sale on ours at Oak, yeah still got two Dom 2 axles I'll let go dirt cheap at the next TQRA race we make it to. Got two brand new dyna tech ignitions, AC skid plate, Elka Sports (all 3), Houser +1 Swing, Fox Floats(fronts), Brand new race harness removes battery, stock harness, and more.

[ratsracung6]

Well found the problem it was the wire harness rubbing against a bolt head and rubed into the wire going from the ECM to the fuse cluster on the left side of the quad. Now looking back every time it blew was going in or coming out of a left hand corner (Crazy).

[TNT]

Originally posted by ratsracung6
Well found the problem it was the wire harness rubbing against a bolt head and rubed into the wire going from the ECM to the fuse cluster on the left side of the quad. Now looking back every time it blew was going in or coming out of a left hand corner (Crazy).

LOl! Don't those sorta electrical things just drive ya nuts! Glad you found it Scott and good luck to your boy. Terry