Nytro Turbo MCX 240 bogs down at idle / problem

[kimoajaj]

Hi guys!

Working on a friends Nytro that seems to run way to rich. The tunnel behind the silencer is all black from smoke. Two years ago I replaced the MCX box due to failure of the old one (startet bogging when trying to build boost), and the sled ran flawless. Next season it started to act up - harsh idle, bogs down at idle, exhaust backfires, just doesn't run right.
It seems to run better at speeds / higher rews, but when coming to a stop it just dies when you let go of the throttle fast.

When I picked it up I was able to ride it into my trailer, when unloading it at the shop, it stopped at idle and I wasn`t able to start it again.

Pulled the tank and changed the plugs. Fired her up but no difference. Noticed that the fuel was very red, turned out the owner had used huge amounts of octane booster. To be sure it was`t causing problems, I pulled the tank again and drained the fuel, put new fuel in, fired her up. At first it seemed to run better but then started to run like crap again.

I tried disconnecting the harness to the MCX injectors, still no difference.
Also tried to use some hose-pliers to cut the fuel to the MCX injectors incase one of the injectors were stuck open - still no difference.


So, I`ve changed plugs, gas, disconnected MCX injectors, also tried to disconnect the MCX box, tried to pull the spark plug caps/coils one at a time while it was idling to make sure it was firing on all cylinders, and I could notice a huge difference when each cap was pulled - so I think the plug caps / coils are OK.


Anyone got any tips?

Here`s a link to a little video of how it runs to make it easier to diagnose.
Noticed some oil fog/mist from the breather, too much or normal ?
Started to suspect holes in piston..

Any help will be highly appreciated!!

 

[Tvatcher700]

I’m having the same issue just on cold starts. Sled been like it since the day the turbo was installed Once it’s warm idles little low but not bad. I turned the 3 screws on the throttle body 1/2 turn and is starting better and idles better, But not perfect.
Gonna follow this post and see if get any answers also.

 

[kimoajaj]

OK I see Tvatcher! But this sled was running like it should before and after the kit was installed, but now it`s acting up.
Wire rub through? OEM injector(s) gone bad from too much octane booster?

 

[Tvatcher700]

OK I see Tvatcher! But this sled was running like it should before and after the kit was installed, but now it`s acting up.
Wire rub through? OEM injector(s) gone bad from too much octane booster?

I been reading bad idle on the turbos could be a vacuum leak. I’m gonna get a can on ether (starting fluid) and spray around places that it could have a vacuum leak. If it idles up when spraying checking for leaks. Means there’s a leak where ever you spray it.