need help with nytro mcx 240

[dicey]

Hi guys ,looking for some input on running issues with 09 nytro mtx with mcx 240 kit, the sled has been turboed since new . the first 2 years the sled ran flawless , I sold it to a friend and he has had nothing but trouble, the problem he is having seems to be with the mcx box that fires the boost injectors, the trouble started last fall, when you would try to ride it would hit about 2 pounds boost and just sputter so we checked everything ,tried blowing in the line to the control box and seemed fixed for a while, have a couple rides where it hardly works so we take the box to the dealer, and they say mcx box is shot. My friend then buys a new box for 800.00 go out once and sled acts the same so back to the dealer,this time with the sled. dealer has the sled for a day they say its fixed but they dont know what was wrong, they say they put dyelectric grease on connections but couldn't make it act up . Surprisingly the sled runs fine the next few rides out, which also bring last riding season to a close. Anyway here we are again this year, first ride out the boost injectors don't fire, blow in the box and it works all day. second ride out it works fine , third ride out spend most of the day messin around again? any help or suggestions pleeeeeease this is getting frusterating:noidea:

 

[up-high]

Sounds like moisture is getting into the box. Take it out and put it on the furnace register overnight(to make sure its completely dry). Then seal the crap out of it with silicone.

 

[summitboy]

What color are the injectors ?

 

[dicey]

brown i think

 

[Northernboy]

Does the MCX box have the small rectangular connector? I found some bad pins in this connector. I repaired them by soldering them, then added Goop to seal the connector and give it strain relief. To test it I just used an ohmeter and measured between positive and negative wires on the harness to confirm there wasnt an open circuit. This was on the bench with nothing hooked up but you can do the same by disconnecting the positive and negative from the sled. I find that's a minor problem with MCX, no feedback saying the box has power or not...a simple LED would be nice.

 

[Thistledoo]

yup electrical problem. Either that gay connection into the box or does it have the fancey connector where it ties into the stock harness?

so falls on its face like getting no extra fuel?

 

[dicey]

I think where it ties in I just unpluged the stock harness pluged the mcx harness in then pluged the stock harness back on the other side. The plug on the box is a rectangle about 1"X 1/4"with mabey 10 pins. Ya falls on its face secondary injectors don't fire.

 

[ROBERTSONYAMAHA]

Also check the wires going to the secondary injectors in the plenum. Have had a couple rub thru in there or get pinched in there. But most common issue is the box. Once you get it fixed use lost of dielectric grease and zip tie it tight to make sure the plug stays straight and tight in the MCX box. - Cody

 

[Thistledoo]

U can bench test it also if u put pressured air into the box while it's idling does it quit like flood out?

Not to much air though. 10 psi is fine.

 

[Nytroman]

I was having the same issue last april. Messed around with wiring, exhaust, unhooked teth air, plugs etc and thought about it over the summer and was a restricted fuel filter. Changed it out yesterday and good to go