MCX Apex won't pull more than 8k rpms

yamymod · Jan 22, 2011

I went out riding today for the first time on the mcx and it ran like crap. it would run ok until around 8000 or 8500 rpms. just about when the boost gage got to around 4 or 5 lbs the motor would cut out and pop. any suggestions would be great. i am wondering about the mcx fuel control box. has anybody had issues like this?

MRFUSION · Jan 22, 2011

Sounds like the aux injectors arent coming on. Unplug the black plug that goes to the injectors in the intercooler and try it. If its the same they arent coming on. Try the wires in the plug in the control box, that is the dumbest idea and have had problems with the little ones pulling out of the plug. If all wiring looks good then sent the control box back. I have had 3 or 4 of these do this. The only flaw in the MCX system as far as I am concerned. Shad

EZmoney · Jan 22, 2011

Could be the box but check the obvious first for boost leaks> Check all connections for loose clamps or leaks and throttle bodies are on correct. Also check for kinked vacuum lines as well.

summitboy · Jan 24, 2011

Which fuel box do you have ? Is it the billet machined one with cooling fins ? If it has a boost line going to it add compressed air 1-4psi to it. As you pass 2 psi you should be able to hear the secondary injectors turning on. If you hear them than thats not your issue. Does the sled run good below 2 psi ? If not it may be a leak in the exhaust maybe bellows ?? If it does run good then i would lean towards the secondary inj.

whitee · Jan 24, 2011

Check your exhaust donuts if its not electrical Hook aup and AFR gauge and see if its going lean or rich

Linc · Jan 24, 2011

Make sure you didn't blow the throttle bodies off the boots, that used to happen alot.

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MCX Apex won't pull more than 8k rpms

yamymod

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MRFUSION

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EZmoney

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summitboy

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whitee

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Linc

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