rb26 in S14 losing power at 6000 rpms

[Newtype]

I have an rb26 in my s14 that i recently purchased and now that im driving it and getting on it i notice that it loses power at 6000 rpms... It doesn't sputter or stall at all.. Just feels as if the fuel and boost are cut and not returned.. I have a afc neo on it now but it was doing it before i installed it.. The set up is a RB26 stock turbos.. mods are fmic, three greddy exhaust, no filters, afc neo. I think thats all.. Running stock boost.. I don't even have a boost controller installed.. Please help.. Its goin on the dyno next week to be trouble shooted but i don't know that much about rbs so im curious if they are notorious for something..? My uneducated guess would be maybe coil packs are cutting out?

[Carl H]

stock ecu and stock cams, sounds pretty normal to me.

[Shocker]

I don't understand why everyone throws on these stupid AFC controllers on. You DONT need it for a stockish setup. The factory ecu can handle it just fine. I know mine did at 11 psi on the dyno and had a nice smooth curve, also pulled fine to redline.......

[gawdzilla]

if the coil packs are suffering or you're losing spark, you will feel the car sputtering/hesitating

[Newtype]

Hm.. Well yeah im running stock ecu and stock cams but that doesn't explain why im losing power.. Im not running out its just when I hit 6000 rpms it seems like fuel and air a regulated down and cut my power in half..

[Shocker]

take the afc off...... thats where I'd start.

[gawdzilla]

is the stock boost solenoid there?

[Newtype]

Well it did it before I put the afc on there.. Um boost cyli ill check when I get home.. Im on my phone now so I don't even know if these posts are showing up right.. Im getting replys so that's a good sign.. Heh.. Im new to the rb26.. Its just something I always wanted so I got it... im also using it to learn of it.. What exactly does the boost cyli do?

[silviasgp06]

officially scared.

so your new to turbo setups too?the boost solenoid is what regulates boost pressure, its a digital ecu controlled bleeder

first off, i do not intend to bash.the rb26 is in my opinion the wrong motor to "start" learning about how performance motors work, but maybe you will catch on quick, but then again most never really fully understand how the stock KA24 motor works before swapping.

before i cross any lines, what is your mechanical/car background anyway?

glad to here you got an rb but please understand it before you mess with it, it will keep you from wasting time and money. good luck, keep us posted

[Newtype]

Well I had an s13 originally and somebody ran into me totalling that.. I bought a new shell and swapped everything over from the old car into the new one.. EVERYTHING! It had an SR which I rebuilt myself.. My dad taught me how to build a motor. I know how most things work on cars.. Everything thats gone wrong on cars ive owned ive fixed myself.. I have probably intermediate mechanical knowledge.. Im new to the RB26 and one thing i understand fully is that the 26 is a lot more expensive to work on and get parts for, there for im more hesistant to work on it. Anything that goes wrong with this motor I will probably have a trusted shop do it because if i screw something up im looking at a much bigger fee than if i were to screw something up in say an SR.. The other thing is one of my friends who owns a shop has taught me to be more open to learning then to act like i know what im doing.. My attitude is much more differen't than it used to be..

Now on this rb at this point in time needs work.. Im having the 6000 rpm issue.. It runs like sh** at an idle due to what i believe is a bad injector in the number four cylinder.. but under boost and load it runs beautifully.. I also need to change the turbo to manifold gasket since one of them is blown. But yeah.. I have no idea why im losing power though..

[PorkChopExpress]

ok, well first thing i would do is

check all vacuum lines. check all sensor connectors. check if the computer is giving you any codes.

then pull the plugs and see what they look like.

start there.

[kevinarich]

take it to that dyno shop and have them run it with the a/f. They can tell you if its a boost problem or a fuel problem just by that.

[Carl H]

could also be the classic rb26 itb gaskets leaking...

[Newtype]

well for an update on this whole thing i havn't been able to work on this issue right now cause my brand new walbro isn't working right.. i wasn't getting anything out of it and now its pumping but barely anything.. so i gotta look into that..

[VanCityGreeD]

Im learning the rb's... Hate to bring back an old thread. What ended up to be the problem?

well for an update on this whole thing i havn't been able to work on this issue right now cause my brand new walbro isn't working right.. i wasn't getting anything out of it and now its pumping but barely anything.. so i gotta look into that..