97 GST shuddering under boost

[ZsGST]

Whatsup guys?
Got me a 1997 GST. I got this car a few months ago and I've been in life with it ever since. I've installed a few parts that I got for cheap from a friend (FMIC, CAI, catback exhaust) and also did a BCS restrictor delete. So, after each shift, I get this half a second to a full second hesitation, and occasionally, when in the middle of a gear under WOT, the car will shudder extremely bad, losing all power and dropping boost for about a full second then go back to normal. The car came with an HKS SSQV, which I recently replaced with a stock recirc off a newer Ralliart (trade), but my issue still persist. Checked for boost leak, but no leak was found. Any ideas?

 

[randman2011]

Yup, I'm with darkness. As long as there are no leaks, it really shouldn't be from intake or FMIC. My first thought was the gap on the plugs because that has caused a stutter on my car more times than I'd care to count. I saw you got new plugs, so if they're gapped properly (.032) then you can rule that out.

I didn't run with the factory injectors on my Spyder for very long, but I was under the impression that they're pretty well maxed out on a stock tune. A boost gauge would confirm that, or running wastegate pressure to drop the boost down. Fuel cut comes from overrunning the MAF, right? That's hard enough on bigger turbos, let alone the stocker at ~factory boost.

DSMLink would definitely help the diagnosis of the problem because you could monitor things like knock retard, injector duty cycle, and estimated boost, but unless you need bigger injectors it won't be required to fix this problem. And if money's tight enough that installing a boost gauge is questionable, now is definitely not the time for Link.

 

[built 97]

sounds like a bit like a fuel cut in a way.

 

[darknezz7]

^^
why trans am

 

[shifty2006]

Yeah the video sounds like fuel cut remove mbc run a hose from actuator to source don't mod boos until you have atleast a boost gauge and wideband

 

[Tigerinstincts]

I agree. Sounds like fuel cut that I had in my 95 gst. It would only happen in higher gears like 4th or 5th gear but mine started at around 4k rpms and it would especially do it 1-2 seconds after punching it. Definitely turn the boost down

 

[ZsGST]

I thought it sounded a lot like fuel cut. A friend of mine says I can't run a CAI without a GM MAF or translator so I'm gonna put the stock air box back on and hope for the best. If not, I'm probably gonna break down and install the boost gauge without my pod.

 

[Zs_GST]

Let me clarify that for some reason I have two accounts, one is my PC account and the other is my iPhone account. Not sure why it's separate like that. Either way, Zs_GST and ZsGST are the same person. I'll try to fix this.

 

[Zs_GST]

Finally an update.

Got the boost gauge installed and decided to uninstall the open element air intake and install a stock air box and a stock 2g recirc bov on it, and believe it or not, it finally stopped shuddering under boost and WOT.

 

[Mauispyder]

I believe it! Thanks for following up. I fixed my biss oring leak and put an Evo bov on this recently, and it pulls so hard now at15 psi that I'm afraid I'll fuel cut too. I don't have a MBC installed though. By the way I "temporarily" installed my boost gauge to the steering column with no slip carpet pad and electric tape and even though I eventually bought a pod, I just left it the way it is Happy DSM'ing!!

 

[Zs_GST]

No problem! I'll be happily DSM'ing right after I fix my blown turbo. Haha

 

[Dsmkauai]

You can run a Cai without a gm maf , never heard that one before haha.

 

[GRAVEDIGGER]

I thought it sounded a lot like fuel cut. A friend of mine says I can't run a CAI without a GM MAF or translator so I'm gonna put the stock air box back on and hope for the best.

It's time to stop listening to that "friend".

 

[Zs_GST]

Hey, in his defense, I removed my CAI and my mystery hesitation disappeared! Lol

 

[Dsmkauai]

But it wasn't from that. Where you running the bov recirculated with the other setup? And what bov. Either the bov was leaking or it wasn't recirculated. Or you had a rip in a coupler. And now with the 2g bov leaking open at 14psi your not making more boost than you can run and fuel cutting haha my guess

 

[Zs_GST]

Yes, BOV was recirculated with the CAI, so it wasn't a BOV issue. Lol

 

[Dsmkauai]

What kind of bov?

 

[Zs_GST]

I actually had a recirc BOV from an '09 Ralliart, I believe it was. Essentially the same design as the stock one. Finally threw a stock BOV on there after awhile, but both still had that issue until I swapped my CAI out with my stock airbox. Lol

 

[Dsmkauai]

So then what kind of Cai was it. And the stock 2g bov sucks balls and cracks open around 14psi. I'm sure that 09 ralliart one has a much tighter spring and holds way more boost! What kind of maf adapter was with the Cai

 

[KayTeeGST]

Whatsup guys?
Got me a 1997 GST. I got this car a few months ago and I've been in life with it ever since. I've installed a few parts that I got for cheap from a friend (FMIC, CAI, catback exhaust) and also did a BCS restrictor delete. So, after each shift, I get this half a second to a full second hesitation, and occasionally, when in the middle of a gear under WOT, the car will shudder extremely bad, losing all power and dropping boost for about a full second then go back to normal. The car came with an HKS SSQV, which I recently replaced with a stock recirc off a newer Ralliart (trade), but my issue still persist. Checked for boost leak, but no leak was found. Any ideas?

I am having same issue and the shudder is so bad in reverse people look at me like I am dumb and can't drive . But my engine light was off for a bit came back on for 3 days and now it's off again got the codes pulled saying egr bank 1 was maybe P3749 i don't remember I'll check again, the other code is a P1400 idk if this would effect if but replaced MAF as well.

 

[OWL79]

It could also be blowing out your spark, a read a reduced gap could cure that

 

[pauleyman]

The root cause may still exist, you just changed the condition that caused it. the video doesnt work. What is the real boost?