Tried it all, still sputtering under boost.

[DrifterE]

Thanks in advance to the people on here that are willing to help. But I have a Redtop SR still stock, stock sidemount, piping, no boost controller, set at stock boost. Just yesterday I was driving to work and I noticed how I can't boost anything without the engine sputtering plenty. I can rev the engine pretty high to about 5k, but if I let it create boost it starts to sputter, and it idles FINE. I am pretty much out of ideas. I have swapped out and checked, the ECU, the TPS, the MAF, the plugs, and I checked all my piping by pumping it with air and listening for leaks. I was hoping all I had was a leak somewhere, but I checked that, and nothing. I know this looks like a very familiar problem to all of us, but is there anything that I might be overlooking? Anyone? Thanks.:naw:

[Matman03]

Did you check the Coil Packs?

[Nduggs]

Did you check the CAS?

[dkwasherexd]

Is it sputtering after you let off the gas after boosting? If it is its boost spike. Your waste gate isnt opening so the extra vacuum pressure is swishing back at your turbo making the sputter sound.

If not that its a boost leak somewhere. Check your couplers, check your side IC and the piping, make sure its tight. If your IC is bad replace it.

Or it could be your turbo is bad, is there shaft play??

[DrifterE]

Well, i didn't check the coil packs just yet. But wouldn't they be good if my idle was good? And the same with my cas?

[Erjay1]

Timing maybe?? I had the same issue except I couldnt rev past 4k rpm. Turns out car had 550cc injectors on the stock ecu. My fix came when I installed my power fc. so maybe check your injectors aswell. Goodluck.

[dkwasherexd]

maybe one of your injectors are stuck and wont open? fuel starvation?

[trmn8r]

only thing i can think of is hooking up a vacuum guage and see if the needle moves eraticly im not sure if your familiar with reading vacuum fluctuations? oh and you cant assume your car is fine because its idleing normal. remember your car acts up under load, two different elements, i did have something happen to me where when im boosting at pretty high rpm i started getting sputtering like you described, and what i found was that one of my coil pack connectors wasnt fully pluged in, and once i pluged it in the car worked fine, id check the connections and your coil packs as well

[DrifterE]

only thing i can think of is hooking up a vacuum guage and see if the needle moves eraticly im not sure if your familiar with reading vacuum fluctuations? oh and you cant assume your car is fine because its idleing normal. remember your car acts up under load, two different elements, i did have something happen to me where when im boosting at pretty high rpm i started getting sputtering like you described, and what i found was that one of my coil pack connectors wasnt fully pluged in, and once i pluged it in the car worked fine, id check the connections and your coil packs as well


By the vacuum fluctuations do you mean pumping the system up with air and checking to see if it changes? I tried that by making a certain tool someone on here or on another forums used, and there wasn't much of a pressure drop or a change or fluctuations when I was filling it. And i checked all my connections to my coils and its all fine. I checked my coils with my DMM and they checked out fine all the same. And you are right, two very different elements, which confuse the hell outta me.

[DrifterE]

Is it sputtering after you let off the gas after boosting? If it is its boost spike. Your waste gate isnt opening so the extra vacuum pressure is swishing back at your turbo making the sputter sound.

If not that its a boost leak somewhere. Check your couplers, check your side IC and the piping, make sure its tight. If your IC is bad replace it.

Or it could be your turbo is bad, is there shaft play??

And its only when I start to build boost or at least try I mean. And I checked couplers, tightened them, and checked for leaks, nothing. Would there still be something wrong with the turbo even tho i'm not getting the blue smoke?

[Mr.GT30]

can u drive ur car?? if yes u can stop by RoadRace Engineering in santa fe spring, around 6pm and i'll try to help u out, shouldn't be that big of issue. oh yeah don't forget ask for LOD