stumbles/misses when accelerating

[talontsi911gawd]

Alright so, just recently i have started having this issue with my 91 eagle talon tsi.. it seems that right after i installed a custom 3" exhaust my car started to stutter when i boosted anything over 7 pounds. it would give the stutter or miss fire that sounded something like spark blowout. so i went though and replaced the spark plugs with the platinum plugs and the issue still occurred. then looking on vfaq i decided to up to the performance plugs, gapped them to .26 and still no luck thinking it would fix the spark blowout. i understand that it could be the wires or coil pack but i just installed a front mount intercooler. after testing the car once it was in, issue was still there with miss fire around 7 pounds. i decided to do a boost leak test and found a few that i have fixed. there still is a small one on the FMIC piping right on the throttle body, which i will fix on my next day off. But just the other night i took the car out for a spin and now when i boost i can hold 12 pounds with out having any issues with misfire, no matter what rpm the engine is at. and i doubt that small leak is causing the miss fire so im wondering what i can do to fix this issue! i have been told to check the maf and also the capacitors in the ecu but just wanna get some expert advice before i start focusing on one major thing.

Also i have noticed that the old vacuum tube that used to run from the stock 14b wastegate to the nipple on the stock intercooler piping coming off the turbo, can no longer be hooked up to the after market intercooler. i have read that this may also be the issue with my car but wondering if the vacuum tube is necessary or what i can do to get it hooked up correctly?

 

[Tyeler18]

So uh.... what is your wastegate hooked up to then?

 

[talontsi911gawd]

ha ha, right now. nothing. i really have no idea where to run the line. its all stock i just dont know where i can run that to on the turbo because there is no nipple. now if im not mistakten can i have that line running anywhere between the turbo and the throttle body? so i can tap it in to say... the air intake ? or run it off the second nipple for the bov?

 

[XiKeiyaZI]

Wait wait wait, where does the line originate from?

 

[talontsi911gawd]

That line is coming right of the stock wastegate attached to the 14b turbo. =]

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This is an image that i found in google, but the line is in the same spot on the wastegate. i assume that is the vacuum line that used to be hooked into the intercooler piping that came right off the turbo.

 

[XiKeiyaZI]

Yes, that line goes straight to a boost source. The most common of this would be a nipple tapped into the charge port on the turbo that the Intercooler coupler clamps onto.

 

[talontsi911gawd]

ok ok so would that be that little nub on the right side of the cold exit on the turbo? but i also have another line on the blow off valve. do you think i can just run this line from the wastegate directly into the second bottom nipple on the bov? And do you think that because if this vacuum line that could be causing the stutter?

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[XiKeiyaZI]

Absolutely not. The bottom nipple on your BOV doesn't need to be utilized. The BOV should have a line dedicated from the top nipple to the intake manifold. This is what keeps the BOV closed or opens it when you let off the throttle when building boost. The Line that goes from the wastegate should run from a dedicated boost source as well. The 'Cold Exit' as you called it usually has a nipple/bung where the hose from the wastegate hooks. It's the exit from the turbo compressor housing.

 

[98GSXtacy]

If there is no nipple on the j-pipe coming off the intercooler just make your own. It's easy and quick just drill a hole, tap it, and thread a barb fitting. Just make sure you use teflon tape on the barbs threads so you won't be leaking any boost. Oh and just to save you from any flaming by some members, it's a 14b not a 14g.

 

[talontsi911gawd]

see now when i look on that 14b turbo, unless its hiding, i dont see any nipple that i can hook it into?

Thanks 98GSXtacy that is a good idea. but do you think that vacuum line is causing my stutter issue? either way i assume im destroying my turbo/engine by not having that wastegate hooked up.

 

[brownfinger]

That's because the j-pipe is not attached to the turbo in that picture.

 

[talontsi911gawd]

That's because the j-pipe is not attached to the turbo in that picture.

Well on the after market intercooler jpipe doesnt have a nipple, so i have to make one like 98gsx said.