Well, if he mistakenly adjusted his MBC incorrectly, and is now overboosting, this could be fuel cut.

He did say that he switched to a new MBC... how did you set this one up?

 

When you moved the MBC back to the original location to check did you use the original hose's or did you cut some new ones?

Athanasios

 

Fuel cut is more of a violent stutter with fireballs coming out of my fart cannon. All my lines have been looked at and diagnosed as neither a hose or leak issue or so I think.

When I put a new Mbc in, I made sure I used NEW hoses and kept them under a foot in length for each line.

Btw people, Evo 7's have a stock antilag system attached to the exhaust manifold. Hoping other 7 owners on here might chime in for similar issues

 

Did you get this resolved? My car just started doing this exact same thing, hits 6k rpm and the wastegate slams shut. I now what you mean about it not feeling like fuel cut. It feels more like a IC pipe blowing off except without the sputter and motor dying?...

Anyone else?... help please

 

Ha ha, turns out my issue was with the maf sensor pinching my bov hose causing the wastegate to shut under full boost. Hope your's is as simple as that.

 

The vehicle speed sensor (VSS) controls the speedo and the odometer. When I did ny clutch job i followed the evom guide and removed the VSS and it apparently was handled too roughly and I had to replace it. I ran without it working for like 3k miles after I did the clutch job due to me being lazy and not wanting to remove everything above the tranny to swap in a new one. It has no effect on the car's ability to run regularly but it is a simple fix for sure (a bit of a pain to undo the clip but one clip and one bolt once you can get to it and its out). I think the evo VII and VIII had a gear driven one but the evo ix is magnetic or a coil sensor. About $70 from the dealer.

My guess is this is a coincidence and can be fixed but is not related to your boost problem. I would lean towards the waste gate too unless the tune was always bad. Have you reflashed to stock? I dont know much about the anti lag systems but seems to be complex enough that it could also cause similar strange issues.

 

i have not reflashed to stock and im starting to believe it is a coincidence.

i just replaced the speed sensor above the transmission yesterday, and the speedo still does not register my mileage ... there goes 70 bucks lol. im assuming its a far more complicated electrical issue than i thought.

i was thinking the wastegate also but if it WAS a wastegate issue id have trouble boosting to begin with. if the door is stuck open or closed wouldnt i be able to see it on my boost guage?

 

No, you have to check your WGDC log. My logs showed 0% (full open) at WOT untill right before peak load 5000-6000rpm then it would slam shut 97% while still WOT followed by fuel cut and 35 counts of knock.

Like you, I didn't touch anything in the tune either. But I remembered that I did take the airfilter off to clean it a couple days earlier before this started happening. Turns out that my BOV vac line was getting pinched under boost causing the WG to slam shut. So now I have my maf almost sideways to clear that hose. It hasn't happened since then. I don't know it might be worth a chance, it'll only take a min to change. GL

 

update: found the source of the problem

i dropped it off with the crew at JDS motoring in port reading, NJ and they unplugged the radio ... legit pulled it out and test drove it.

car works perfectly lol

the wiring diagram for the 8 and 9's are different from the 7's. something went wrong or something was being grounded or improperly tapped or something. but they found the source of the issue.

 

Awesome, glad you got it sorted out. Wow that is a weird one.

Also found the real souce of my fuel cut, my licp had a huge dent and leak in it.