Bucking under boost

[2ggst1998]

So my dsm cuts power under boost. But it does it in 2nd gear mostly. I dont notice cut of power in 1st. Does anyone know the problem. Its got a greddy intake, intercooler piping and greddy bov. Thanks

 

[Dsmkauai]

What boost? And what kind of cut? Like fuel cut or boost leak? Have u done a Blt?

 

[2ggst1998]

it was a fuel cut at first. But then i was under the car just unspecting and i found a mbc covered in dirt (which is random, i dont understand y it was down there). But i noticed it was way too tight. So i loostened it and now it doesnt feel like fuel cut it feels more like a boost leak. so ill check for boost leaks now. But it feels like it stutters alot under wot in any gear other than first. Any ideas? Thanks!!

 

[evil_eagletalon]

Boost leak test
Fuel Cut
Or could be just spark plugs need regapping or replacing.

 

[2ggst1998]

Ya i did replace plugs and wires onit because of a stutter it had under boost. But that is gone now but it seems like around 4500 rpm the boost fades and then it bucks and cuts power. so to me it feels like a fuel cut and boost leak. what do you think?

 

[DSMrightontime]

Can we get a follow up here? I'm having very similar issues with a 97 GST Spyder. Began after a Clutch master replacement and clutch drag test. My mechanic and i are stumped!!! FPS read open, but that shoudln't cause this condition right??!! Also car has been running pig rich...

 

[DSMrightontime]

Jeez. I'm having similar issue. Mine bucks hard after boost spikes above 14psi. EVERY time I pass 14psi it happens. It was good until I removed boost restrictor in bcs. Any ideas? Sorry for the thread jack

 

[miliman13]

Erh-megurd!!! Me too.. Guys it's many of us,! Nothing ever works, that has for someone else. Sucks right being in the dark. There is like dozens of threads unfinished and unanswered...

 

[DSMrightontime]

Hella frustrating!

 

[DSMrightontime]

I made a post, too. Hopefully we get some help!

 

[Type1DSMr]

Jeez. I'm having similar issue. Mine bucks hard after boost spikes above 14psi. EVERY time I pass 14psi it happens. It was good until I removed boost restrictor in bcs. Any ideas? Sorry for the thread jack

Have you checked your plugs and done a boost leak test? Any cel when it happens?

Erh-megurd!!! Me too.. Guys it's many of us,! Nothing ever works, thank had for someone else. Sucks right being in the dark. There is like dozens of threads unfinished and unanswered...

Still not running right man. That sucks it's be a while.

 

[DSMrightontime]

Yup. Brand new bpr6es, and boost leak good to 14psi

 

[Type1DSMr]

Yup. Brand new bpr6es, and boost leak good to 14psi

What gap and have you pulled them out since issue? Try to boost leak test to 20 psi. Do you have a wideband or any logging device?

 

[miliman13]

Have you checked your plugs and done a boost leak test? Any cel when it happens?


Still not running right man. That sucks it's be a while.

I know right!!!!! School keeps me busy man. I plan to run an array of new test during the turkey brake. Cuz starting Dec im completely disassembleling the motor blue printing and machining for D=m/v and real power. I'm hoping my Tuner will fix it if it's still there by the time I finish the assembly.

 

[miliman13]

Richness points to loss of spark and air. But finding it ....... Yeah.

 

[Type1DSMr]

I know right!!!!! School keeps me busy man. I plan to run an array of new test during the turkey brake. Cuz starting Dec im completely disassembleling the motor blue printing and machining for D=m/v and real power. I'm hoping my Tuner will fix it if it's still there by the time I finish the assembly.

I hear ya there, I work on my car in between study breaks . I thinking about pulling my motor also on winter break to do the timing and what not. Keep it updated with pics in your build or posting.

 

[DSMrightontime]

Gapped at 28 to avoid spark blowout, and we're talking 5 days... I'll blt at 20psi and see what happens. But even at a few psi would the leak be so bad to cause the issue?

 

[Type1DSMr]

Gapped at 28 to avoid spark blowout, and we're talking 5 days... I'll blt at 20psi and see what happens. But even at a few psi would the leak be so bad to cause the issue?

Yeah even a small leak can cause a world of problems. Because you shouldn't be boosting to 18 psi and settling in at 14 psi from removing the bcs. Points to a leak.

 

[DSMrightontime]

ok, i'm on that. major leak possibilities; Injector seals, tb?

i just did, thoroughly, fmic and piping, so that should be good.

 

[Type1DSMr]

All of the above are major areas. Also look for how long it takes to bleed out and make sure you do a proper boost leak test. Check your exhaust manifold, turbo housing, o2, dowpipe, etc for cracks and worn out gaskets.