2008 mcx apex MTX backfiring!!!

Push T Nytro

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Just wondering if anyone has ever had this problem on a mcx 260 apex. It does not idle, when I push on throttle it seems to load up with fuel and is very hesitant, when rpm gets to 3000 it cleans out and runs good, then while accelerating when turbo starts to create boost pressure (between 6000 and 7000 rpm) it starts to backfire and pop (sounds like a lean pop). Have no idea what is wrong, need some pointers!
 

bigfish

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sounds like you have a boost leak check your intercooler make sure all the boots are still on.
 

Lund

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Just wondering if anyone has ever had this problem on a mcx 260 apex. It does not idle, when I push on throttle it seems to load up with fuel and is very hesitant, when rpm gets to 3000 it cleans out and runs good, then while accelerating when turbo starts to create boost pressure (between 6000 and 7000 rpm) it starts to backfire and pop (sounds like a lean pop). Have no idea what is wrong, need some pointers!

FYI while trying to find the problem that might help.
4stroke motor will not "backfire" if running rich or "bog". If these symptoms happen it is always a "lean" condition. Unlike a 2cycle.
Check your fuel pressure and make sure your motor is getting adequate fuel supply. An intake leak like a damange cooler ect. ect will lead to boost pressure lost and lost of performance.
What kind of controller you using, is it adjustable?
Plus what is your fuel being used and what kinda boost is being applied?

Did you take anything appart recently? Also a out of adjustment TPS will cause similar issues, but generally only fall out if tampered with.
 
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Nytroman

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Had a similar issue with my nytro last year, idled okay but soon as started to see boost would pop and sputter and fall flat. Looked at everything, finally cut my fuel filter apart and it was plugged. new one and good to go. It was a clear one and it looked clean but wasn't.
 

overkill131313

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I went out 2 nights ago and my apex did the same thing......fuel controller was not censing boost so I put a new fuel controller and it was great last night......
 

CatAttack900

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Buddy Had same issue a few years ago with his nytro mcx kit. Sled would pop when on higher boost, found out that it was not getting enough fuel ( one Bad injector). He Replaced injector and it fixed the issue.
 

MC Xpress

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Can just about guarantee one of the small vacuum hoses blew off the intercooler, bov, or MCX control box. Would create the vacuum leak causing poor idle and when spooled up boost signal wouldn't get to the map sensor in the control box telling it to fire the aux injectors thus causing the lean pop you hear at 6-7 psi. Follow the line from your control box to all connections. Look for cracks or a line blown off the fitting. I zip tie every connection especially if running higher boost.

Cheers
LL
 
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