Hey all, finally put my Buschur MBC on the car (03 VIII) and went to go dial it in. Did the pulls in 3rd and 4th and got the boost to 21 and it holds great....
UNTIL about 45oo rpm, when the car sputters and backfires HARD. I did some hasty searching on here and couldnt really get anything. All the lines are securely attached, and the stock boost solenoid is capped off (just looped a piece of tubing from one nipple to the other). The line going into the bottom of the intake tube has also been capped. I have no idea what the issue is or how to fix it....ANY help would be GRAND!!!!

Thanks in advance

 

Since you say all connections are ok, back down the boost, maybe you are overboosting and your gage isn't measuring it???

Also how old are your plugs??? Are you tuned for 21psi??? Do you have an aftermarket intake???

 

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stock intake, but I do have a K&N drop in. I backed the boost down and tried it, and when I did that it did do the same thing, but closer to 5 grand....plugs are a bit old, and after searching some I am going to get some new plugs tomorrow, just dont know if its maybe something I did wrong or whatever (i have been known to screw up simple shish before lol) Compressor line is running to the bottom feed on the MBC and the top feed it going to the wastegate actuator. was I wrong in capping the intake nipple?

 

Yeah this crossed my mind as well, I have a cheap "glowshift" gauge, 30psi

 

Untuned?

Boost cut.

 

With your mods, you definitely are in need of a tune. When I installed my MBC, I only capped off one of the boost solenoid nipples ( with the pill) and left the other one attached. Double check, no, triple check all of your connections and then try turning the boost to around stock. Then report back

 

Sounds like fuel cut. Back the MBC down more.

 

Try gapping your spark plugs to .025"

 

Yeah I dont have a tune yet. Ive had the ECU opened up, basically to just clean up some of the knock, install the no lift and 2 step, that was it....what should I turn the boost down to, bout 18? So I should un cap the line from the stock boost solenoid to the intake and leave it inline?

 

Thats what I did.

 

Well I backed the boost down some, to about 15-16 psi and did a couple other 3rd gear pulls. Same thing happened, and actually, in second gear after it started boosting a little (no i wasnt doing a pull) it seemed like it just cut completely off, almost like it stalled out; it kicked back in a split second later. Im going to try and run the line from the stock boost solenoid to the nipple on the bottom of the intake tube and see if that has anything at all to do with it. I think I may call buschur tomorrow too if nothing comes of it.....any recommendations for plugs? Also, what is it exactly that would make the plugs go bad almost instantly (other than age). Id like to learn as much about the stuff im having problems with, not just to get me out of a hole, but so i know down the line and have a better understanding

 

^ same thing.....im f***in getting p***ed off now....this is gonna keep me up all night lmao....It also seems to be really sluggish when I fisrt get on the gas. I just filled up 2 days ago with 93 octane (exxon) and put my typical Chevron fuel system cleaner in as well, like always after an oil change. Upon start-up, it seems like it wants to die out also, but very faintly and just for a split second, but it has never done that before...Would it maybe be worth it to try "t"ing off the BOV line?

 

Running excessively rich will kill plugs in no time. If you were holding boost at 21-22, and were able to turn it down, then it's not your boost controller imho. Change those plugs out. Sounds like a fuel or spark issue. On a side note, does it allow you to keep revving beyond the 4500-5000? Is it possible you are hitting a rev-limit? You said you added the tephra mods, so I would think this could be a possibility.

 

i pulled the 2 step right from the ecu, im tryin to find some plugs right now, nobody has any, which doesnt surprise me at all